ArticlePDF Available

Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern Morocco

Pensoft Publishers
ZooKeys
Authors:

Abstract and Figures

The geological and paleoenvironmental setting and the vertebrate taxonomy of the fossiliferous, Cenomanian-age deltaic sediments in eastern Morocco, generally referred to as the “Kem Kem beds”, are reviewed. These strata are recognized here as the Kem Kem Group, which is composed of the lower Gara Sbaa and upper Douira formations. Both formations have yielded a similar fossil vertebrate assemblage of predominantly isolated elements pertaining to cartilaginous and bony fishes, turtles, crocodyliforms, pterosaurs, and dinosaurs, as well as invertebrate, plant, and trace fossils. These fossils, now in collections around the world, are reviewed and tabulated. The Kem Kem vertebrate fauna is biased toward largebodied carnivores including at least four large-bodied non-avian theropods (an abelisaurid, Spinosaurus, Carcharodontosaurus, and Deltadromeus), several large-bodied pterosaurs, and several large crocodyliforms. No comparable modern terrestrial ecosystem exists with similar bias toward large-bodied carnivores. The Kem Kem vertebrate assemblage, currently the best documented association just prior to the onset of the Cenomanian-Turonian marine transgression, captures the taxonomic diversity of a widespread northern African fauna better than any other contemporary assemblage from elsewhere in Africa. Keywords Africa, Cretaceous, dinosaur, Gara Sbaa Formation, Douira Formation, paleoenvironment, vertebrate
This content is subject to copyright. Terms and conditions apply.
Kem Kem Group of Morocco 1
Geology and paleontology of the Upper Cretaceous
Kem Kem Group of eastern Morocco
Nizar Ibrahim1, Paul C. Sereno2, David J. Varricchio3, David M. Martill4,
Didier B. Dutheil5, David M. Unwin6, Lahssen Baidder7, Hans C.E. Larsson8,
Samir Zouhri9, Abdelhadi Kaoukaya7
1 Department of Biology, University of Detroit Mercy, Detroit, Michigan 48221, USA 2 Department of Or-
ganismal Biology and Anatomy and Committee on Evolutionary Biology, University of Chicago, Chicago, Il-
linois 60637, USA 3 Department of Earth Sciences, Montana State University, Bozeman, Montana 59717,
USA 4 School of the Environment, Geography and Geological Sciences, University of Portsmouth, Portsmouth
PO1 3QL, UK 5 Centre de Recherche sur la Paléobiodiversité et les Paléoenvironnements, UMR7207 (CNRS-
MNHN-UPMC), Muséum national d’Histoire naturelle, 75005 Paris, France 6 School of Museum Studies,
University of Leicester, Leicester LE1 7RF, UK 7 Laboratoire Géosciences, Département de Géologie, Faculté
des Sciences Aïn Chock, Université Hassan II, Casablanca, Morocco 8 Redpath Museum, McGill University,
Montreal, Quebec H3A 0C4, Canada 9 Laboratoire de Biodiversité et Santé, Faculté des Sciences Aïn Chock,
Université Hassan II, Casablanca, Morocco
Corresponding author: Nizar Ibrahim (ibrahini@udmercy.edu), Paul C. Sereno (dinosaur@uchicago.edu)
Academic editor: Massimo Delno|Received 23 October 2019|Accepted 2 March 2020|Published 21 April 2020
http://zoobank.org/6C47C920-CBBC-4A7C-A05F-1E12D13076F1
Citation: Ibrahim N, Sereno PC, Varricchio DJ, Martill DM, Dutheil DB, Unwin DM, Baidder L, Larsson HCE,
Zouhri S, Kaoukaya A (2020) Geology and paleontology of the Upper Cretaceous Kem Kem Group of eastern
Morocco. ZooKeys 928: 1–216. https://doi.org/10.3897/zookeys.928.47517
Abstract
e geological and paleoenvironmental setting and the vertebrate taxonomy of the fossiliferous, Cenom-
anian-age deltaic sediments in eastern Morocco, generally referred to as the “Kem Kem beds”, are re-
viewed. ese strata are recognized here as the Kem Kem Group, which is composed of the lower Gara
Sbaa and upper Douira formations. Both formations have yielded a similar fossil vertebrate assemblage
of predominantly isolated elements pertaining to cartilaginous and bony shes, turtles, crocodyliforms,
pterosaurs, and dinosaurs, as well as invertebrate, plant, and trace fossils. ese fossils, now in collections
around the world, are reviewed and tabulated. e Kem Kem vertebrate fauna is biased toward large-
bodied carnivores including at least four large-bodied non-avian theropods (an abelisaurid, Spinosaurus,
Carcharodontosaurus, and Deltadromeus), several large-bodied pterosaurs, and several large crocodyliforms.
ZooKeys 928: 1–216 (2020)
doi: 10.3897/zookeys.928.47517
http://zookeys.pensoft.net
Copyright Nizar Ibrahim et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC
BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
MONOGRAPH
Launched to accelerate biodiversity research
A peer-reviewed open-access journal
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
2
No comparable modern terrestrial ecosystem exists with similar bias toward large-bodied carnivores. e
Kem Kem vertebrate assemblage, currently the best documented association just prior to the onset of the
Cenomanian-Turonian marine transgression, captures the taxonomic diversity of a widespread northern
African fauna better than any other contemporary assemblage from elsewhere in Africa.
Keywords
Africa, Cretaceous, dinosaur, Gara Sbaa Formation, Douira Formation, paleoenvironment, vertebrate
Table of contents
Introduction ............................................................................................................. 3
Geological status and presumed age ................................................................... 3
Paleoenvironmental and paleoecological interpretations ..................................... 7
Fossil discoveries ................................................................................................ 8
Vertebrate fauna ................................................................................................. 8
Institutional and collections abbreviations ................................................................ 9
Materials and methods ........................................................................................... 10
Fieldwork ......................................................................................................... 10
Collections research .......................................................................................... 13
Geographic feature names ................................................................................ 14
Geology .................................................................................................................. 15
Geological context............................................................................................ 15
Hamadian Supergroup ..................................................................................... 25
Kem Kem Group ............................................................................................. 27
Gara Sbaa Formation ....................................................................................... 27
Douira Formation ............................................................................................ 35
Paleogeography and paleoenvironments ........................................................... 45
Age .................................................................................................................. 51
Taphonomy ............................................................................................................ 53
Systematics ............................................................................................................. 64
Plant and nonvertebrate fossils ......................................................................... 64
Elasmobranchii Bonaparte, 1838 ..................................................................... 64
Actinopterygii Klein, 1885 ............................................................................... 73
Sarcopterygii Romer, 1955 ............................................................................... 76
Amphibia Gray, 1825 ....................................................................................... 82
Testudines Batsch, 1788 ................................................................................... 83
Squamata, Oppel, 1811 ................................................................................... 91
Crocodyliformes Hay, 1930 ............................................................................. 92
Pterosauria Kaup, 1834 .................................................................................. 112
Dinosauria Owen, 1842 ................................................................................. 125
Discussion ............................................................................................................ 172
Stratigraphic resolution .................................................................................. 172
Kem Kem Group of Morocco 3
Biostratigraphic resolution ............................................................................. 173
Taxonomic resolution ..................................................................................... 174
Kem Kem assemblage ..................................................................................... 176
Comparable African assemblages .................................................................... 182
Conclusions ......................................................................................................... 185
Kem Kem paleoenvironments ........................................................................ 185
Kem Kem paleoecosystem .............................................................................. 187
Acknowledgements ............................................................................................... 189
References ............................................................................................................ 190
Introduction
Richly fossiliferous strata, commonly referred to as the “Kem Kem beds” (Lavocat
1949, Sereno et al. 1996), are exposed on the face of a long, winding escarpment near
the Moroccan-Algerian border on the northwestern edge of the Sahara Desert (Figs
1–3). Secondary outcrops of similar rocks extend westward toward the Atlas Moun-
tains from this escarpment at Erfoud to Jorf and eventually to Goulmima and Asa.
At distant locales in northern Africa, early geological and paleontological surveys iden-
tied comparable fossiliferous rocks in the Western Desert of Egypt (Stromer 1915,
1934, Nothdurft et al. 2002) and in north and central regions of the Sahara (Haug
1904, Lapparent 1951, 1960, Depéret and Savornin 1927).
e Kem Kem beds, nevertheless, are more fossiliferous, better exposed and often
more accessible than comparable strata in most other northern African locations. ese
strata have been studied by several teams and are accessible to locals in some areas; fos-
sils have been collected by researchers aliated with institutional collections as well as
local private collectors that often utilize commercial intermediaries. Our aim in this
report is to review both the geological and paleontological aspects of the Kem Kem
beds, to describe and name strata as needed, to summarize the taxonomic status of the
fauna based on all major collections of Kem Kem fossils, and to evaluate paleoenviron-
ments and the paleoecological signicance of the Kem Kem assemblage.
Geological status and presumed age
Lavocat (1954a, 1954b) referred to the strata in the Kem Kem area of Morocco as a
component of the “Continental intercalaire”, a term used for broadly comparable rocks
in many other locales in northern Africa that are capped by a distinctive hard lime-
stone platform of Cenomanian-Turonian age (Figs 3, 4). Lavocat (1948, 1954a) and
Choubert (1952) also referred to this continental-marine package of rock as the "trilo-
gie mésocrétacée", comprising two successive continental units underlying the marine
Cenomanian-Turonian limestone. e continental beds were described by Joly (1962)
as the "unité inférieure", or "grès rouges infracénomaniens", and the "unité supérieure",
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
4
Erfoud
Taouz
Ouzina
Gara Sbaa
Zguilma
K
e
m
K
e
m
H
a
m
a
d
a
50 km
N
Hassi
G
u
i
r
H
a
m
a
d
a
123
4
56
7
8
9
RABAT
Casablanca
Marrakech
Errachidia
30o
10o5o
Morocco
0 400 km
ATLAS MTNS
Kem Kem
beds
AC
B
Figure 1. Geographical setting of the Kem Kem region and outcrops. A View of the position of Morocco
in Africa and location of the Kem Kem beds (shown in red). B Map showing the geographical location of
the Kem Kem in North Africa relative to roughly coeval sites in northern Africa. C Cretaceous outcrops
along the Kem Kem and Guir Hamadas (modied from Sereno et al. 1996). Numbers: 1 Kem Kem,
Morocco. 2 Gara Samani, Algeria. 3 Timimoun, Algeria. 4 Monts des Ksours, Algeria. 5 Djoua Valley,
Algeria. 6 Al Hamra Hamada, Libya. 7 In Abangharit, Niger. 8 Bahariya, Egypt, 9 Tataouine, Tunisia.
or "marnes versicolores à gypse." is two-part division of the continental facies be-
neath the Cenomanian-Turonian limestone along the escarpment in the Kem Kem
region of Morocco has thus been recognized for nearly 70 years, although no formal
geological nomenclature has been proposed for these fossiliferous continental facies.
Sereno et al. (1996) introduced the informal term Kem Kem beds for the two
lower units of Choubert’s (1952) “trilogie mésocretacée”, which underlie the Cenom-
anian-Turonian limestone complex (Fig. 3). ese lower beds, composed of sandstone
and mudstone, reach a maximum thickness of approximately 200 m. More recently,
Ettachni and Andreu (2004) and Cavin et al. (2010) used formational names origi-
nally proposed in notes to a geological map of the High Atlas to the northwest of the
Kem Kem by Dubar (1949; sometimes mis-cited as 1948). Dubar’s formational names
(Ifezouane and Aoufous) are based on his observations of strata on the eastern ank
of the High Atlas Mountains (Tinghir, west of Goulmima). As we discuss below, these
rocks are generally un-fossiliferous, have a greater presence of evaporite facies, and lack
other features of both terrestrial units of the Kem Kem beds (Sereno et al. 1996). us,
although we do correlate the two units of the Kem Kem beds with the Ifezouane and
Aoufous formations on a continuum of relatively small interconnected basins, we show
that the Kem Kem units are mappable, distinctive and deserving of formal recognition,
and we designate eective type sections for each. We summarize the latest geological
and paleontological evidence that suggests that they accumulated on a continental
ramp in the Kem Kem region through to ocean margins to the north and west (Fig. 2).
Kem Kem Group of Morocco 5
1
2
3
4
Figure 2. Geographical setting of the Kem Kem region. Cenomanian (~94 Mya) paleogeographic world
map showing key localities (map after Scotese 2002, da Silva and Gallo 2007). Abbreviations: 1 Kem Kem
region in Africa 2 Tethys Ocean 3 opening Atlantic Ocean 4 South America.
Figure 3. Outcrops of the Kem Kem sequence near Gara Sbaa. e red beds are overlain by a Cenoma-
nian-Turonian limestone platform.
e age of the “Kem Kem beds” has been regarded variously as mid or early Late
Cretaceous (Albian-Cenomanian). Lavocat (1948) described the most common fau-
nal elements and estimated the age as Albian or Cenomanian. Choubert (1952) and
Lavocat (1954b) noted similarities with the Bahariya Formation in Egypt (Stromer
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
6
Figure 4. Example Kem Kem localities. A Basal outcrop at Aferdou N’Chaft B Iferda N’Ahouar CGara
Sbaa D Other outcrops at Gara Sbaa E Outcrops south of Jbel Zireg F Outcrop at Moher (south of
Tafraoute) near the Morocco-Algeria border.
1936, Dominik 1985, Soliman and Khalifa 1993), which was regarded as Cenoma-
nian in age. Choubert (1952) and Lavocat (1954a), however, assigned the Kem Kem
beds to the "infracénomanien," suggesting a probable Albian age. Although ammo-
nites and other nonvertebrate fossils have established the Late Cenomanian-Turonian
age of the overlying limestone complex (Ferrandini et al. 1985; Ettachni and Andreu
2004; Ettachni et al. 2005; Essafraoui et al. 2015), no fossils were known at that
time from the Kem Kem beds that could be reasonably associated with stage-level
temporal resolution.
Kem Kem Group of Morocco 7
Seven elasmobranchs and several dinosaur genera (Spinosaurus, Carcharodonto-
saurus, and Deltadromeus) reported from the Kem Kem beds are shared with the Ba-
hariya Formation in Egypt (Sereno et al. 1996). One of these elasmobranch species
(Haimirichia amonensis; Cappetta and Case 1975), in addition, has a broad circum-
Mediterranean distribution seemingly restricted to Cenomanian strata. As the fauna
from both lower and upper units appears similar, Sereno et al. (1996) inferred a
Cenomanian age for these sediments, which has generally been accepted (Wellnhofer
and Buetaut 1999, Cavin et al. 2001, Dal Sasso et al. 2005, Cavin et al. 2010).
Martin and de Lapparent de Broin (2016) recently reviewed the geology and age of
the Kem Kem beds and proposed a late Albian-early Cenomanian age for the locality
that yielded Lavocatchampsa.
Paleoenvironmental and paleoecological interpretations
Paleoenvironmental interpretations of the Kem Kem beds all agree on their conti-
nental status, but dier in regarding either uvial and oodplain deposits (Russell
1996), or deltaic facies with rare lacustrine environments, as predominant (Sereno et
al. 1996). Cavin et al. (2010) described the Kem Kem beds as mostly terrestrial with
local brackish and freshwater deposits.
Paleoecological interpretation has centered around the taxonomic and numerical
dominance of predators and, more specically, piscivorous terrestrial and aquatic verte-
brates. Based on a collection of commercially acquired fossils, Russell (1996) suggested
that the abundance of sh served as the primary resource for a diversity of piscivorous
crocodyliforms and theropods, and later authors have added supporting evidence (Ser-
eno et al. 1996, Russell and Paesler 2003, Läng et al. 2013, Ibrahim et al. 2014a). Oth-
ers have regarded this as an oversimplication of a more complex food web (McGowan
and Dyke 2009, Cavin et al. 2010).
A notable feature of the Kem Kem assemblage is the taxonomic, numerical and
ichnological dominance of theropods among dinosaurs. Some authors regard this as an
accurate reection of the dominance of theropods in the fauna during the Cenoma-
nian (Russell 1996, Mahler 2005, Läng et al. 2013, Ibrahim et al. 2014a, Ibrahim et al.
2014b, Ibrahim et al. 2016). Others have suggested that the perceived diversity (Dyke
2010) and abundance (McGowan and Dyke 2009, Cavin et al. 2010, Dyke 2010) of
theropods is a result of geological or collecting biases. As many of the fossils are based
on isolated remains, there are ongoing questions over the taxonomic diversity of some
subgroups including theropods (e.g., Evers et al. 2015).
With a similar approach, it has been suggested that Kem Kem fossils as a whole
represent a “compound assemblage” derived from two formations (Cavin et al. 2010)
or from disparate paleoenvironments (Dyke 2010). e geological and paleontological
evidence reviewed in this report bears directly on these controversies.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
8
Fossil discoveries
In the late 1940s, Choubert (1948) described bony sh from the Kem Kem beds
exposed on the escarpment of the Guir Hamada along the Morocco-Algeria border.
From 1948 to 1951, Lavocat brought to light a range of vertebrate fossils, prospecting
and collecting on camelback and vehicle along the escarpment formed by the Guir and
Kem Kem Hamadas (Lavocat 1949, 1954a, 1954b, Lapparent 1958). His best-known
fossil discovery is the partial skeleton of the diplodocoid sauropod, Rebbachisaurus gar-
asbae (Lavocat 1954b, Wilson and Allain 2015) from the locality Gara Sbaa (Fig. 4C).
During the following 45 years from 1950–1995, only sporadic, small-scale eld-
work was undertaken. In the 1970s a small team led by German scientist Helmut Al-
berti collected fossil vertebrates near Taouz at the northeastern end of the escarpment
of the Kem Kem Hamada (pers. com. M. Reich to NI, 2007). e fossils, housed at the
University of Göttingen, include isolated remains of cartilaginous and bony sh, cro-
codyliforms and non-avian dinosaurs. e coelacanth remains were described by Wenz
(1981), and some jaw remains were referred to Spinosaurus (Buetaut 1989, 1992).
Russell (1996) described a collection of commercially acquired fossils, probably
collected from the Kem Kem beds, assigning specimens to Carcharodontosaurus saha-
ricus, a new species, Spinosaurus maroccanus, a new genus and species Sigilmassasaurus
brevicollis, and an unnamed abelisaurid. Sauropod bones were referred to Rebbachisau-
rus garasbae and a family of basal titanosauriforms.
In the last 25 years, paleontologists brought to light a diverse array of new verte-
brate fossils (e.g., Sereno et al. 1996, Ibrahim et al. 2010, Cavin et al. 2010, Ibrahim
et al. 2014a). Commercial fossil collecting in the Kem Kem beds has also accelerated
during this time. Many of the fossils described in recent years were acquired from
commercial sources of uncertain geographic origin (e.g., Wellnhofer and Buetaut
1999, Ganey et al. 2002, Milner 2003, Evers et al. 2015, Hendrickx et al. 2016).
ese specimens, with very rare exception, are isolated bones recovered from channel
deposits with no locality information or taxonomic association.
Vertebrate fauna
e Kem Kem beds have revealed an important and remarkably diverse vertebrate as-
semblage including elasmobranchs, osteichthyes, and basal sarcopterygians (Choubert
1939, Tabaste 1963, Wenz 1981, Forey 1997, Forey and Grande 1998, Taverne and
Maisey 1999, Cavin and Dutheil 1999, Dutheil 1999a, 1999b, Cavin and Brito 2001,
Taverne 2000, 2004, Cavin and Forey 2001a, 2001b, Filleul and Dutheil 2001, 2004,
Cavin and Forey 2004, Forey and Cavin 2007, Cavin et al. 2010, Martill and Ibrahim
2012), amphibians (Rage and Dutheil 2008), lepidosauromorphs (Rage and Dutheil
2008, Apesteguía et al. 2016a, Klein et al. 2017), turtles (Gmira 1995, Tong and Buf-
fetaut 1996, Ganey et al. 2002, 2006), crocodyliforms (Buetaut 1976, 1994, Lars-
son and Sidor 1999, Larsson and Sues 2007, Sereno and Larsson 2009, Martin and de
Kem Kem Group of Morocco 9
Lapparent de Broin 2016, Young et al. 2017), pterosaurs (Wellnhofer and Buetaut
1999, Mader and Kellner 1999, Ibrahim et al. 2010, Rodrigues et al. 2011, Martill
and Ibrahim 2015, Martill et al. 2018, 2020, Jacobs et al. 2019, 2020, McPhee et
al. 2020), non-avian dinosaurs (Lavocat 1948, 1951, 1952, 1954b, Buetaut 1989,
1992, Sereno et al. 1996, Russell 1996, Milner 2003, Amiot et al. 2004, Novas et al.
2005a, Mahler 2005, Dal Sasso et al. 2005, Ibrahim at al. 2014a, Ibrahim et al. 2014b,
Evers et al. 2015, Ibrahim et al. 2016, Chiarenza and Cau 2016, Ibrahim et al. 2017),
and a possible avian (Cavin et al. 2010).
Kem Kem vertebrates are typically preserved in two general taphonomic situa-
tions, most commonly in clastic uvial or deltaic facies or, rarely, within a lake, or
pond, facies at the locality Oum Tkout. In the predominant uvial facies, isolated and
transported fossils are the norm. Only three associated partial dinosaur skeletons have
been recovered, the diplodocoid sauropod Rebbachisaurus garasbae (Lavocat 1954b,
Wilson and Allain 2015) and the theropods Deltadromeus agilis (Sereno et al. 1996)
and Spinosaurus aegyptiacus (Ibrahim et al. 2014b). In addition, one associated dino-
saur skull pertaining to the large theropod Carcharodontosaurus saharicus has been re-
covered (Sereno et al. 1996). Because of the prevalence of isolated remains, taxonomic
identication of some Kem Kem vertebrates remains controversial, with some authors
splitting and others lumping recorded taxonomic diversity (Russell 1996, Sereno et al.
1996, Mahler 2005, Rauhut and López-Arbarello 2006, Averianov et al. 2008, Cavin
et al. 2010, Ibrahim et al. 2014b, Evers et al. 2015, Ibrahim et al. 2017).
e lentic waters and ne bottom mud at Oum Tkout preserve leaves, crustaceans
(prawn, macruran decapod), and the intact skeletons and scales of bony sh (Dutheil
1999b, Filleul and Dutheil 2001, 2004, Garassino et al. 2006). e specimens are ac-
quired by quarrying and splitting blocks followed by ne preparation. Multiple speci-
mens of a given taxon are often preserved.
Institutional and collections abbreviations
BSPG Bayerische Staatssammlung für Paläontologie und Geologie, Munich,
Germany (formerly BSP)
CMN Canadian Museum of Nature, Ottawa, Canada (formerly NMC)
FMNH Field Museum of Natural History, Chicago, USA
FSAC Faculté des Sciences Aïn Chock, Casablanca, Morocco
IMGP Institut und Museum für Geologie und Paläontologie, University of Göt-
tingen, Göttingen, Germany
LINHM Long Island Natural History Museum, Long Island, USA
MN Museu Nacional/Universidade Federal do Rio de Janeiro, Rio de Janeiro,
Brazil
MFN Museum für Naturkunde, Berlin, Germany
MNHN Muséum national d’Histoire naturelle, Paris, France
MNBH Musée national Boubou Hama, Niamey, Niger
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
10
MPDM Musée Parc des Dinosaures, Mèze, France
MSNM Museo Civico di Storia Naturale, Milan, Italy
NHMUK Natural History Museum, London, United Kingdom
ROM Royal Ontario Museum, Toronto, Canada
SGM Service Géologique du Maroc, Rabat, Morocco
UCRC University of Chicago Research Collection, Chicago, USA
Materials and methods
Fieldwork
In 1995 a joint expedition from the University of Chicago and the Service Géologique
du Maroc explored southern outcrops of the Kem Kem beds beween Erfoud and Hassi
Zguilma (Fig. 1C). Geological sections were logged at intervals, which comprise the
majority of the stratigraphic sections presented in this report (Sereno et al. 1996). No-
table paleontological nds included the discovery of a partial postcranial skeleton of the
theropod Deltadromeus agilis in the upper part of the lower unit. Near the base of the
upper unit, a pond locality named Oum Tkout was discovered with complete remains
of decapods and articulated bony sh (Dutheil, 1999b). e upper unit also yielded a
partial skull of the theropod dinosaur Carcharodontosaurus saharicus and footprint ho-
rizons including the only record to date of an ornithischian dinosaur in the Kem Kem
assemblage (Sereno et al. 1996). Dozens of macro- and micro-vertebrate fossil locali-
ties were mapped and hundreds of isolated fossils and footprints were collected. ese
specimens currently reside in the University of Chicago Research Collection.
In 2007 and 2008, joint expeditions from University College Dublin, the Uni-
versity of Portsmouth and the Faculté des Sciences Aïn Chock (Casablanca) collected
fossils and recorded ichnological, taphonomic, and sedimentological data, focusing on
seven sites between Erfoud and Hassi Zguilma (Tables 1–3, Figs 4, 5; Ibrahim et al.
2014a, 2014b, 2016). Vertebrate fossils include bony shes, turtles, crocodyliforms,
the large azhdarchid Alanqa saharica (Ibrahim et al. 2010, Martill and Ibrahim 2015),
and dinosaurs, including a partial humerus of a large titanosaurian sauropod (Ibrahim
et al. 2016). ese specimens reside in the collections of the Faculté des Sciences Aïn
Chock in Casablanca.
In 1999, 2000, 2002, and 2011, eld work was undertaken at the pond local-
ity Oum Tkout by a joint team from the Muséum national d’Histoire naturelle, the
Service géologique du Maroc, and the University Cadi Ayyad. Quarrying operations
resulted in the discovery of numerous nonvertebrate fossils (plants, insects, ostracods,
decapods, etc.) as well as articulated elasmobranchs and actinopterygians. Much of this
material remains to be thoroughly prepared and studied and likely represents several
new taxa.
In 2013, eld work was undertaken by a joint team from the University of Chi-
cago, the Museo Civico di Storia Naturale (Milan), and the Faculté des Sciences Aïn
Kem Kem Group of Morocco 11
Table 1. Presence in three research collections of specimens from 15 localities in the Kem Kem Group.
Abbreviations: FSAC Faculté des Sciences Aïn Chock, Casablanca, Morocco MNHN Muséum national
d’Histoire naturelle, Paris, France UCRC University of Chicago Research Collection, Chicago, USA.
Number Locality FSAC MNHN UCRC
1 Aferdou N’Chaft/Ouzina
2 Boumerade/Gara Acacia
3 Dar el Karib
4 Douira
5 Gara Sbaa
6Gara Tabroumit
7 Iferda N’Ahouar
8Kouah Trick
9 Moher
10 Oum Tkout
11 Talidat
12 Taouz
13 Valley near Boumerade
14 Zguilma
15 Zrigat
Table 2. Six fossil vertebrate localities with geographic coordinates prospected during eld work in 2008.
Coordinates for other localities may be obtained with permission from the authors.
Number Locality Geographic coordinates
North East/West
1 Aferdou N’Chaft 30°53'51.23"N 3°52'13.42"E
2 Boumerade 30°32'49.00"N 4°42'55.45"E
3 Douira 31°38'16.93"N 4°20'20.23"E
4 Gara Sbaa 30°30'40.64"N 4°50'42.87"E
5 Iferda N’Ahouar 30°47'54.33"N 4°22'43.74"W
6 Zguilma 30°12'07.61"N 5°7'11.48"E
Table 3. Taphonomic stages for bone abrasion from transport (following Anderson et al. 2007).
Stage Identication Description
1 Very angular Bone and teeth fresh and unabraded
2 Subangular Bone edges slightly abraded and polished
3 Subrounded Bone edges moderately rounded
4 Rounded Bone edges and processes broken and rounded
5 Extremely rounded Marked abrasion of all external surfaces
Chock (Casablanca) to explore a locality (Zrigat) approximately 20 km north of Er-
foud, where a partial skeleton of Spinosaurus aegyptiacus was discovered by a local col-
lector (Ibrahim et al. 2014b: g. 1A). Additional fragmentary pieces of this specimen
were recovered at the site, and the specimen is catalogued in the collections of the
Faculté des Sciences Aïn Chock. A geological section was logged across both units of
the Kem Kem beds at the nearby Al Gualb Mesa, positioning this locality at the base of
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
12
Figure 5. Outcrop near Boumerade, identied in 2008. A Flat erosional surface yielding fossils (turtle
and pterosaur) B Sloped erosional surfaces yielding fossils (turtle). Abbreviations: 1 Collecting surface 2
Boundary between upper and lower members 3 Locality of a partial turtle carapace.
the upper unit (Ibrahim et al. 2014b: g. 1B). Additional eldwork in the Kem Kem
was performed in 2015 on an expedition led by one of us (NI).
In 2018 and 2019, a multidisciplinary team of scientists from the University of
Detroit Mercy, the Faculté des Sciences Aïn Chock, the Museo Civico di Storia Natu-
Kem Kem Group of Morocco 13
rale (Milan), and the University of Portsmouth, led by NI, explored a number of sites
along the Kem Kem escarpment, including several new localities. Finally, regular eld-
work by University of Portsmouth researchers and students has continued to grow the
Casablanca collection (Faculté des Sciences Aïn Chock).
Collections research
Besides major collections in Casablanca (Faculté des Sciences Aïn Chock), Paris (Mu-
séum national d’Histoire naturelle), and Chicago (University of Chicago), additional
collections were assembled over the last 50 years from privately acquired specimens
collected by locals in villages near the Kem Kem escarpment, although without specic
locality data. During a general survey of the Kem Kem beds in 1995, excavation pits
in channel sandstones made by local collectors were observed along the entire length
of the outcrop. Commercial collecting was therefore already well established by the
mid-1990s along most of the available outcrop of the Kem Kem beds with activity
concentrated in the northern one-half between Erfoud and Taouz.
e most important collections of commercially collected fossils are in Canada
(CMN, Ottawa; ROM, Toronto) and Europe (MNHM, Paris; MPDM, Mèze; BSPG,
Munich; MSNM, Milan; NHMUK, London). Several authors (PCS, DMM, DBD,
HCEL) have visited some of these collections; one author (NI) has visited all the major
collections in the course of doctoral research at University College Dublin, collecting
quantitative data on thousands of specimens (Fig. 6, Table 3).
Figure 6. Examples of specimen measurements. A Turtle carapace fragment (MRS 172, MNHN specimen)
B Femur (MPDM 270) in anterior and lateral view. Scale bars equal 2 cm in A and 10 cm in B. Abbrevia-
tions: 1 Length of specimen 2 Width measurement 3 Maximum length measurement 4 Depth measurement.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
14
Geographic feature names
Geographic feature names are often cited or adopted for geographic locations, fossil
localities and geological terms. Whereas the Geological Survey maintains an authorita-
tive federal database for geographic feature names in the United States (Geographic
Names Information System), no such resource is currently available for Morocco. In
the Sahara, geographic feature names often originate in Arabic or Amazigh (Berber)
languages and exhibit considerable spelling variation in scholarly papers in German,
French or English. Sometimes the meaning of feature names is lost, as may be the case
with the most salient feature name in this study, Kem Kem. If a specic meaning to
feature names persists, nevertheless, that meaning is often unknown to western schol-
ars. To remedy that situation, we have compiled a list of important fossil localities in
the Kem Kem region along with their meanings and spelling variants (Table 4).
Variation in usage can run counter to the original meaning of the name or the fea-
ture to which it was originally applied. e term “Talalt”, for example, is an Amazigh
word referring to a jar made of clay for water and was used as a feature name for the val-
ley of oases south of Errachidia in eastern Morocco. It is used to refer to pre-Mesozoic
(mostly Paleozoic) outcrops in the scientic literature (e.g., Wendt et al. 1984, Baidder
et al. 2016). It should not be used to describe the Kem Kem escarpment or the loca-
tion of the Kem Kem vertebrate fauna (Russell 1996), which derives from a larger area
extending much farther to the south.
Other variation in geographic names is the result of ocial name-changing, with
older names on geological maps and reports supplanted by newer names. “Ksar es-
Souk”, for example, is Arabic meaning “fortied village of the market” and was the
longstanding name of a pivotal city in east-central Morocco. In the 1970s it was re-
named “Errachidia”. Both names have several spelling variants. Neither should be used
with “Province” as the location for the entirety of the Kem Kem outcrop (e.g., Kellner
and Mader 1997, Weishampel et al. 2004). e relatively large administrative area of
Errachidia Province does not include the southern one-half of the exposures of the
Kem Kem beds.
Some geographic names are simple errors that gain traction in secondary citations.
In a prominent compilation of dinosaur localities, for example, the term “Tegana For-
mation” was cited for the “Kem Kem beds” (Weishampel et al. 1990). is may have
arisen as a misspelling of the “Tegama Group”, a name for Cretaceous age beds in Ni-
ger. Although the error was noted (Sereno et al. 1996), it has reappeared in subsequent
publications (e.g., Bailey 1997, Kellner and Mader 1997, Taverne and Masey 1999,
Weishampel et al. 2004).
In this report, we formally name several geological units, abiding by the guidelines
of the North American Stratigraphic Code (NACSN 2005). Sereno et al. (1996) previ-
ously introduced the informal geological term “Kem Kem beds” for the fossiliferous
outcrop of the Kem Kem region. Some authors have mistakenly referred to the “Kem
Kem Formation” (e.g., McGowan and Dyke 2009, Holliday and Gardner 2012), when
no formal geological unit by that name was ever proposed.
Kem Kem Group of Morocco 15
Geology
Geological context
“Continental intercalaire”. e Kem Kem beds correlate to the top of a package of
continental sediments in basins across northern Africa referred to by Kilian (1931) as
the “Continental intercalaire”, or the “intercalated continental (deposits)”. In many
regions, the beds assigned to the “Continental intercalaire” discordantly overlie Paleo-
zoic marine sediments that Kilian termed the “Continental de base”. ey are over-
lain, in turn, by a prominent limestone plateau and younger sediments he termed the
“Continental terminal”. Additional informal subdivisions (between the three outlined
by Kilian; Table 5) have been inserted by geologists and paleontologists from time to
time, prominent among them Lapparent and Lelubre (1948). Despite its widespread
use, “Continental intercalaire” remains an evolving, poorly dened stratigraphic term.
Below we question its utility.
e stratotype for the “Continental intercalaire” is located in the Djoua Valley in
Algeria. Rocks of comparable age are located in continental basins to the east in Libya
and Egypt, to the north and west in Tunisia, Morocco and Mauritania, and to regions
south of the Hoggar Mountains in Niger (Lavocat 1954a, Bellion et al. 1990, Lefranc
and Guiraud 1990, Sereno et al. 1996, Benton et al. 2000, O’Leary et al. 2004). Lappar-
ent and Lelubre (1948) and Lefranc (1958) described and divided strata of the “Con-
tinental intercalaire” across northern Africa, delineating a number of “series” (Table 6).
e lower boundary is problematic. It does not correspond to any geological event
across northern Africa. Kilian (1931) suggested the lower boundary should include
all marine sediments of Carboniferous age (thus including the Tiguentourine series;
Table 6). Later papers inferred a Triassic age for the earliest beds (Kilian 1937, Lefranc
1958, 1963, Busson 1970), whereas Lapparent (1949) included only the Cretaceous
Table 4. Nomenclature of Kem Kem localities and geographic terms and their meanings in Arabic or
Amazigh (Berber language).
Locality/Term Meaning Synonym/Variant
Aferdou N’Chaft (aferdou) mortar, (n’chaft) “of the
pass” (Amazigh)
“El Begâa” (Cavin et al. 2010) refers to the closest village
near the locality here identied as Aferdou N’Chaft
Boumerade acacia (Amazigh) “Gara Acacia” by Lavocat on eld records and museum
labels for the locality here identied as Boumerade
Douira small house (Arabic) “Jorf” refers to the closest village to the outcrop here
identied as Douira
Gara Sbaa lion hill or mound (Arabic) “Gara es Sbaa” (Sereno et al. 1996), “Gara Sbâa” (Cavin et
al. 2010)
Hamada plateau or platform (Arabic)
Iferda N’Ahouar (iferda) mortars, (n’ahouar) large
plate (Amazigh)
“Er Remlia” (Sereno et al. 1996) refers to the closest village
to the outcrop here identied as Iferda N’Ahouar
Oum Tkout particular Tamarix tree (Amazigh) “Oum Tkiout” (Martill and Ibrahim 2015)
Talidat little nger (Amazigh)
Tamenkhirt common songbird (wheatear)
(Amazigh)
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
16
Table 5. Divisions of northern African sediments. Kilian’s (1931) three terms (in italics), dened in the
Djoua Valley near the Algerian-Libyan border, were supplemented by Lapparent and Lelubre (1948) (mod-
ied from Lefranc and Guiraud 1990). Abbreviation: ICS International Commission on Stratigraphy.
ICS timescale Division
Danian-Pleistocene Continental terminal
Late Cenomanian-Danian Continental hamadien
Namurian-Late Cenomanian Continental intercalaire
Frasnian-Namurian Continental post-tassilien
Ordovician-Frasnian Continental tassilien
Cambrian Continental de base
Table 6. Subdivisions of the “Continental intercalaire” introduced by Lapparent and Lelubre (1948) and
Lefranc (1958) (modied from Lefranc and Guiraud 1990). Abbreviation: ICS International Commis-
sion on Stratigraphy.
Division Sediment series ICS timescale
Hamadian series limestone platform Cenomanian-Turonian
Continental intercalaire Djoua series Early Cretaceous
Taouratine series Jurassic
Zarzaitine series Triassic
Tiguentourine series Late Carboniferous (Pennsylvanian)-Permian
Post-tassilian series marine limestone Early Carboniferous (Mississippian)
outcrops of the Djoua series (Table 5) in the “Continental intercalaire”. In their review,
Lefranc and Guiraud (1990) identied a lower boundary that includes Late Paleozoic
strata “younger than Namurian”, although many of these largely un-fossiliferous beds
are dicult to correlate. Some authors exclude contemporaneous continental rocks
in coastal basins from the “Continental intercalaire”. Cavin et al. (2010: 393), for
example, exclude the fossiliferous Upper Cretaceous strata in marginal basins along
Moroccos Atlantic coast.
e upper boundary of the “Continental intercalaire”, in contrast, is bounded by
a well-dated, fossiliferous Late Cenomanian-Turonian limestone platform (Fig. 7),
which may be the reason the term has persisted. e limestone platform records a sud-
den global transgression (Gale 2000) that is well exposed in Morocco (Kilian 1931,
Lefranc and Guiraud 1990, Choubert 1948, Lavocat 1954a, Ferrandini et al. 1985, Et-
tachni and Andreu 2004). e nearshore and terrestrial strata underlying the platform
in Morocco correspond with the Djoua series in Algeria, although their precise correla-
tion is poorly constrained. ese underlying strata include the Kem Kem beds, which
rank amongst the most fossiliferous continental beds of the “Continental intercalaire”.
In sum, there is no consensus regarding the lower boundary of the “Continental
intercalaire”, which has never been tied to any regional geological event or episode.
Some coeval continental rocks of Cretaceous age, in addition, are excluded because
of their location in coastal basins. For these reasons, we question the continued use
of “Continental intercalaire” as a heuristic term in discussions of northern African
continental strata.
Kem Kem Group of Morocco 17
Late Cenomanian-Turonian carbonate platform. Choubert (1948) recognized the
Late Cenomanian-Turonian platform (“Calcaires cénomano-turoniens”) as the uppermost
unit of his “trilogie mésocrétacée”. e carbonate platform was rst described in detail by
Ferrandini et al. (1985: 561, g. 2) on the basis of a stratotype section at Akrabou (cited as
Akerboûss”) approximately 45 km north of Erfoud. Ferrandini et al. (1985) and Ferran-
dini (1988) divided the platform into four successive subunits, the lower three within the
Late Cenomanian and the last in the Turonian, with ages based on considerable biostrati-
graphic evidence. e subunits, which represent successive transgressive facies (coastal,
reef, interior platform, and benthic platform), were not formally designated as members.
Additional sections were logged across the Akrabou Formation (at Ziz near Akra-
bou and at Tadighoust 50 km to the west) by Ettachni and Andreu (2004), who also
identied four subunits. Only the lower two were placed within the Late Cenomanian;
the upper two units were regarded as Turonian in age. A little farther west in the High
Atlas Mountains, Ettachni et al. (2005) divide the Cenomanian-Turonian platform
into ve subunits, describing it as a new formation (Ben Cherrou Formation). Only
the lowest subunit is regarded as Late Cenomanian in age, whereas the upper four are
assigned to the Turonian. To the east across the Algerian border in the Béchar region,
Benyoucef et al. (2012: g. 2) divide the platform into four subunits dated by ammo-
nites and other nonvertebrate fossils, the lower three of which were regarded as Late
Cenomanian in age and only the uppermost Early Turonian.
Figure 7. Outcrops of the "Continental intercalaire infracenomanien" in the Kem Kem (near Gara
Sbaa). Lines separate the Cenomanian-Turonian platform that caps the "Continental intercalaire" from
the upper and lower units.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
18
Correlation between sections of the Cenomanian-Turonian platform in central
Morocco is challenging, because of lateral variation in the character and age of plat-
form subunits. Transgressive conditions, nonetheless, characterize all of these sections,
which grade upward from shallow-water coastal facies to a more massive, deeper-water
(subtidal) carbonate platform (Ferrandini et al. 1985). e platform complex also
markedly thickens to the north of what Essafraoui et al. (2015) identify as the “Kem
Kem embayment”, on which the uvio-deltaic Kem Kem beds were deposited. e
platform is typically ~ 30 m thick over the Kem Kem beds. It rapidly thickens north of
Aoufous to 90 m at Tazouguerte, which is located only 50 km northeast of Aoufous.
Far to the north in the Anoual Syncline of the High Atlas, the Cenomanian-Turonian
platform is often thinner, measuring ~ 20 m in thickness.
Kem Kem beds and embayment. e Kem Kem beds are exposed along the gen-
erally western-facing escarpment of the Guir and Kem Kem Hamadas. Capped by the
Late Cenomanian-Turonian platform, the escarpment extends north-south approxi-
mately 200 km near the Morocco-Algeria border (Figs 1A, C, 8–11). e northern
boundary of the outcrop is located approximately 30 km south of Errachidia (near
Zrigat). It extends southeasterly toward Taouz, following the western edge of the Guir
Hamada. From there it extends southwest along the western edge of the Kem Kem
Hamada, diving under the low outcrop of the platform ca. 30 km north of Mhamid.
e Kem Kem beds rest unconformably on fossiliferous marine Paleozoic rocks
of Silurian, Devonian, and Cambrian age, a contact exposed only in few areas (Figs
12, 13A). e escarpment, generated by Cenozoic erosion (Schmidt 1992), varies in
topographic height from ca. 50 to 200 m (Figs 10–12). As much as 90% of the face of
the escarpment is covered by limestone talus from the capping Cenomanian-Turonian
platform. Available Kem Kem outcrop, therefore, is considerably less than the rela-
tively continuous band shown on regional geological maps. Exposures most often are
isolated patches or on the anks of ravines. Broader areas of outcrop of the Kem Kem
beds occur only in regions where the escarpment is prominent, such as near Zrigat,
Gara Sbaa and Iferda N’Ahouar.
e Kem Kem beds comprise two units representing predominantly deltaic depo-
sition on a northeast-southwest trending ramp recently termed the “Kem Kem embay-
ment” (Essafraoui et al. 2015: 140, g. 2). e Kem Kem embayment is bounded to
the west by the Anti-Atlas and to the east by the Bechar promontory (Essafraoui et al.
2015). e “Taouz Basin” (Cavin et al. 2010) is another name applied to the structural
depression that received sediments in the Kem Kem region. Deposition within this
depression constitutes reactivation of the Paleozoic “Talalt Basin” in the same area
(Wendt 1985, Bockwinkel et al. 2013).
Essafraoui et al. (2015: 162) used published sections (Cavin et al. 2010) and satel-
lite images to conclude that the Kem Kem beds “thin to the south” and were laid down
on a “South to North dipping (Tethyan-oriented), low-gradient ramp”. e strati-
graphic sections and paleocurrent data we logged during eldwork in 1995, 2008, and
2013 conrm the main thrust of this interpretation. e exact thickness of the lower
unit of the Kem Kem beds often cannot be established, because the contact with the
Paleozoic is usually covered. e upper unit and the overlying limestone, nevertheless,
Kem Kem Group of Morocco 19
Figure 8. Schematic and simplied geological cross section from the southern Atlas mountains at Amel-
lagou to the northern margin of the Hamada du Kem Kem at Ouzina spanning the Talalt Platform. No-
tice that the Kem Kem Group strata overlie a thick Mesozoic sequence in the north within the southern
Atlas Mountain thrust belt but rest unconformably on the Paleozoic basement in the south. Likely the
Taalt Platform was an 'island' within the gigantic Kem Kem river system. e line of sections extends
from A at Amellagou to B at Ouzina.
Figure 9. Landsat image of southeastern Morocco showing key localities, villages and cities, modied
from Ibrahim et al. 2010. Scale bar equals 25 km. Abbreviations: 1 Tiknioune Bou Tazoult (just east of
Zguilma), 2 Talidat, 3 Jbel Sdila, 4 Iferda Timenkhirt, 5 Gara Sbaa, 6 Oum Tkout, 7 Boumerade, 8 Mo-
her, 9 locality just south of Zireg, 10 Daoura, 11 locality of the neotype of Carcharodontosaurus saharicus
(Sereno et al. 1996), 12 Iferda N’Ahouar west, 13 Iferda N’Ahouar east, 14 Aferdou N’Chaft, 15 Hmar
Lakhdad, 16 Douira Tagemout.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
20
Figure 10. Jagged limestone talus from the overlying Cenomanian-Turonian platform at Gara Sbaa
obscures the majority of the outcrop of the Kem Kem Group.
thin to the south toward Hassi Zguilma and to the east toward Taouz. e Kem Kem
beds, thus, do appear to have been deposited on a low-gradient ramp opening to the
north, with sediments derived from the Anti Atlas Massif to the west and lowland
regions to the south and east in southern Algeria (Busson 1970).
Northeastern Kem Kem equivalents. Continental beds underlying the Cenoma-
nian-Turonian platform are also exposed in the Béchar area of western Algeria north-
east of the Kem Kem embayment. Lapparent (1960) reported on isolated bones and
teeth of fossil vertebrates from these beds that are similar to those of the Kem Kem
fauna. More recently, Benyoucef et al. (2012, 2014, 2015) documented the presence
under the carbonate platform of coastal sabkha deposits in the Guir Basin of western
Algeria. ese deposits of Cenomanian age, although much thinner (~ 10 m) than the
Kem Kem beds, have yielded a fauna broadly comparable to that reported here from
the Kem Kem beds (Benyoucef et al. 2015). ese data led Essafraoui et al. (2015) to
conclude that a north-dipping, low-gradient ramp also existed during the Cenomanian
on the Algerian side of the western Saharan craton.
Northern Kem Kem equivalents. e so called “Sillon Préafrican”, or Pre-African
Trough, trends southeast-northwest between the Anti-Atlas Massif to the south and
the Central and Eastern High Atlas to the north. e trough follows a major rift system
(South Atlas Fault or Front) that separates the northern Atlas and Rif regions from the
African craton proper to the south (Fig. 13A). Possible equivalents of the Kem Kem
beds are preserved on the shoulders, or margins, of the trough and taper in outcrop
Kem Kem Group of Morocco 21
width from Meski and Aoufous in the west to Goulmima and Tinghir in the east,
where they pinch out.
Just a few kilometers north of Zrigat near Aoufous, there are two units of red beds
underlying the limestone platform along the Meski-Aoufous Hamada. ese beds lack
the well-developed cross-bedding common in the lower unit of the Kem Kem beds
and are considerably thinner, markedly gypsiferous, and barren of footprints or fossils
(Fig. 14). Less than 10 km to the southeast near Zrigat, by contrast, both units of the
Kem Kem beds are thick and well developed, as fully exposed and measured on the side
of Al Gualb Mesa (Ibrahim et al. 2014b: supplementary Information). Not far from
that mesa, a typical Kem Kem fauna was recovered, including a partial skeleton of the
dinosaur Spinosaurus aegyptiacus (Ibrahim et al. 2014b).
Farther east near Goulmima, a generalized geological section shows the carbonate
platform and underlying marl sediments that could correlate with the upper unit of
the Kem Kem beds (Cavin et al. 2010: g. 3). e published section, however, did not
include signicant sandy deposits down-section that might correspond with the lower
unit of the Kem Kem beds. Condence in correlation with units of the Kem Kem beds
was further weakened by the absence of fossils.
One of us (DMM), however, discovered a better outcrop approximately 10 km
to the north of Goulmima at a locality near Tadighoust known as Asa. Both units
comparable to those of the Kem Kem beds are exposed, although the facies dier from
those typical of the Kem Kem beds. e lower unit has mudstones that pass upward
into more typical channel sandstones, although commonly these are more cemented
Figure 11. e escarpment at Gara Sbaa serves as a geographic landmark in the Kem Kem region.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
22
Figure 12. Paleozoic strata in the Kem Kem and Talalt regions. A Unconformity at Iferda N’Ahouar
BDevonian outcrop at Hmar Lakhdad (Fig. 9: locality 15) C Geopetal inll structures in Devonian strata
near Hmar Lakhdad. Abbreviations: K Cretaceous Pz Paleozoic.
than in the Kem Kem region. e upper unit is ner-grained, as in the Kem Kem beds,
but signicant gypsiferous evaporates are more common. Fossils appear to be absent
from the upper unit but are present, if rare, in the cemented sandstones of the lower
unit. Vertebrate teeth recovered pertain to the sawsh Onchopristis, the theropod cf.
Carcharodontosaurus, and a large, subconical tooth pertaining to either a crocodylo-
morph or spinosaurid.
Farther to the west on the anks of the High Atlas near Tinghir, a similarly more
complete section is present and was visited by one of us (DBD). Two units are present
under the carbonate platform that correspond well with the two units of the Kem Kem
beds (Gauthier 1960, Essafraoui et al. 2015). e ner-grained upper unit, neverthe-
less, has more marine marls, marine sandstones, a beach sandstone, and gypsiferous
Kem Kem Group of Morocco 23
Figure 13. Tectonic setting of the Kem Kem region. A Major tectonic complexes in southeastern Mo-
rocco (modied from Baidder 2007) B Kem Kem Hamada fault lines (top unnamed, bottom Omjrane-
Taouz fault, Google Imagerie 2010 Digital Globe). Abbreviations: AAMF Anti Atlas Major Fault EF
Erfoud Fault F fault line TF Taouz Fault.
evaporate beds than typical in the corresponding Kem Kem unit (Essafraoui et al.
2015: g. 16). e lower sandy unit shows ripple marks and occasional bioturbation
as in the Kem Kem beds, but lacks the tiered cross-bedding common in the Kem Kem
beds. Unlike the Kem Kem beds, vertebrate fossils are very rare and none have been
gured (Gauthier 1960).
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
24
Figure 14. Continental red beds at Aoufous.
Choubert (1948), who described the Kem Kem beds, was aware of these infra-plat-
form continental deposits but thought they were laid down in an Atlasic basin separate
from the Kem Kem embayment. Using satellite images, Essafraoui et al. (2015) de-
scribed Tinghir-like infra-platform deposits around the margins of the Anti Atlas Massif,
which they regarded as the likely source of terrigenous input for these beds during the
Cenomanian. Perhaps that accounts, in part, for the dierence in lithology from compa-
rable units in the Kem Kem embayment, which also appear to have had terrigenous in-
put from the south. No matter their sediment source, we agree with the overall Cenoma-
nian correlation outlined by Essafraoui et al. (2015), linking more coastal (Tinghir) and
inland (Kem Kem) regions regarding the carbonate platform and two underlying units.
Marked lithologic, ichnological and paleontological dierences, however, suggest dier-
ing depositional conditions and favor the distinction of these units as lateral equivalents.
e two units in the Tinghir region have come to be called, in succession, the If-
ezouane and Aoufous formations. Ettachni and Andreu (2004: 278) and Cavin et al.
(2010: 393) attributed authorship of the Ifezouane, Aoufous, and Akrabou formations
to Dubar (1949; cited as “Dubar 1948”). Although it may have been Dubar’s intention
to replace Choubert’s (1948) “trilogie mésocrétacée” with formations, no formation
names, stratotypes or type localities are mentioned in this publication, which com-
prises notes accompanying a geological map of the High Atlas in the region of Midelt.
ese formation names appear to have been adopted in 1997 in notes accompanying a
more recent geological map of the region around Tinejdad to the south of Goulmima
(Ettachni and Adreu 2004: 279). e next citation of these formation names appears
to have been in a doctoral dissertation (Rahlmi 2000).
Kem Kem Group of Morocco 25
Given that notes to maps and dissertations are often dicult to obtain and of
limited distribution, neither are considered “adequate publication” by the North
American Stratigraphic Code (NACSN 2005). Here we suggest that stratotypes be
recognized for the Ifezouane, Aoufous, and Akrabou formations based on the most
detailed published sections, which are located at Tinghir (Essafraoui et al. 2015: g.
16), Goulmima (Ettachni and Andreu 2004: g. 12), and Akrabou (Ferrandini et al.
1985: g. 2), respectively.
Far north Kem Kem equivalents. Red bed units that may also correspond to the
Kem Kem beds are situated some 50 km north in the Anoual Syncline in the eastern
High Atlas, a basin known for yielding a diverse Lower Cretaceous (Berriasian) ver-
tebrate assemblage including mammals and dinosaurs (Hahn and Hahn 2003, Knoll
and Ruiz-Omeñaca 2009, Lasseron et al. 2019). e section extends upwards from
these fossiliferous horizons to units immediately below a capping Cenomanian-Turo-
nian platform. In 1995 fossils were collected from localities in the Lower Cretaceous
beds and a section was logged across well-exposed Cretaceous outcrop immediately
north of the well at Aïn Mellouk. No fossils were found in the two units immediately
below the Cenomanian-Turonian platform, which in this region has a depth of ~ 20 m.
More recent geological and paleontological work in the Anoual region has resulted
in the naming of several formations and the establishment of a better temporal frame-
work based on recovered fossils (Haddoumi et al. 1998). e coarser-grained Dekkar
2 and ner-grained Dekkar 3 formations were named for the beds underlying the
Cenomano-Turonian platform (Haddoumi et al. 2016: g. 2). ese formations bear a
strong general resemblance to the lower and upper units of the Kem Kem beds, located
some 500 km to the south. e Dekkar 2 Formation, for example, is composed of
ne-grained marls interleaved with sand- and silt-stones, calcarenitic lenses, and gyp-
sum evaporates. e overlying Dekkar 3 Formation, in contrast, is ner-grained and
composed principally of marls interleaved with thin-bedded carbonate and gypsum
evaporites (Haddoumi et al. 2016).
Haddoumi et al. (2016) tentatively regarded the Dekkar 2 Formation as Aptian in
age, although the only fossils on which the date could have been established are charo-
phytes, ostracods and bivalves near the base of the unit. e Dekkar 3 Formation was
regarded as Cenomanian in age; it must predate the Late Cenomanian age of the base
of the overlying limestone platform. ese ages, therefore, broadly correspond with the
age of the Kem Kem beds.
Dekkar formations 2 and 3 are preceded by Dekkar Formation 1, a coarse-grained
unit lacking vertebrate remains and tentatively regarded as Barremian to Aptian in age.
ese Dekkar formations compose the Dekkar Group, bounded below by an uncon-
formity and above by the Cenomanian-Turonian platform.
Hamadian Supergroup
Here we recognize the Hamadian Supergroup for a package of continental rocks across
north Africa (Table 7), exemplied in central and eastern Morocco where they were
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
26
Table 7. Designation and correlation of Hamadian Supergroup and Kem Kem Group strata in central
and eastern Morocco as proposed in this study. Hamadian Supergroup strata have been historically re-
ferred to as the “trilogie mésocrétacée” (Choubert 1948). e three strata composing the trilogy in the
Kem Kem region include the Gara Sbaa, Douira and Akrabou formations. Stage and substage calibrations
are based on ammonite zonation in western Europe (Voigt 2000).
Stage/Age Substage Lithostratigraphic
units
Central and Eastern Morocco
South, (Kem Kem) Central, (Tinghir) North, (Anoual)
Turonian,
93.5–89.0 Ma
Upper Hamadian
Super-
group
Akrabou Formation
Middle
Lower
Cenomanian,
99.0–93.5 Ma
Upper
Middle Kem Kem
Group
Douira Formation Aoufous Formation Deckar 3 Formation
Lower Gara Sbaa
Formation
Ifezouane Formation Deckar 2 Formation
rst identied as the “trilogie mésocrétacée” (Choubert 1948). e name derives
from the Arabic word “hamada”, or rocky plateau, which refers to the resistant Upper
Cenomanian-Turonian carbonate platform that forms barren plateaus across broad
areas of northern Africa. Softer underlying sediments of sandstone, mudstone and
marl are exposed on the edges of these resistant plateaus. e carbonate platform has
yielded vertebrate fossils as well as a rich nonvertebrate fauna of Late Cenomanian and
Early Turonian age. e softer underlying deltaic and marginal marine sediments are
the source of most of what is known about terrestrial vertebrate life on Africa during
the Early and Middle Cenomanian.
e Hamadian Supergroup includes strata laid down during a sustained, stepwise
transgressive trend during the Cenomanian and Early Turonian. e rocks record a
global eustatic second-order stratigraphic cycle that generated a tripartite rock record
in continental areas, with two rock units underlying a carbonate platform. e under-
lying formations are deltaic or near shore, the rst coarser-grained than the second, the
base of which can often be recognized by sustained and signicant mudstone deposi-
tion. Several pairs of formations of this general description are recognized below as
regional manifestations of the Kem Kem sequence.
e “Hamadian series” or “Continental hammadien” (Lefranc and Guiraud 1990)
are little used terms coined by Kilian (1931, 1937) for marine strata across northern
Africa situated between the “Continental intercalaire” and “Continental terminal” (Ta-
bles 5, 6). ey included the Late Cenomanian-Turonian carbonate platform and vari-
ous younger strata of the early Paleogene (Danian). Unfortunately, the upper boundary
of this package of units is ill-dened, much like the lower boundary of the “Conti-
nental intercalaire”. e problematic upper boundary is limited only by the overlying,
poorly dated, terrestrial rocks of the “Continental terminal”.
We recommend, by contrast, the aptly named Hamadian Supergroup as a heuristic
term that includes rocks related to a sustained transgressive stratigraphic cycle that are
well exposed across northern Africa. e age of initial deposition is best estimated as
Early Cenomanian in the Kem Kem region (see below), and the upper boundary of
Kem Kem Group of Morocco 27
deposition of the carbonate platform is well established as the end of the Early Turo-
nian (Ferrandini et al. 1985, Ettachni and Andreu 2004, Ettachni et al. 2005). In
this report, we do not extend correlations of the Hamadian Supergroup to northern
African formations farther aeld (i.e., outside Morocco). We anticipate future stud-
ies will extend correlations across northern Africa, anchored by the well-exposed Late
Cenomanian-Turonian cli-forming carbonate platform.
Kem Kem Group
Here we recognize the Kem Kem Group for rocks in central and eastern Morocco that
comprise the rst two non-marine units of the Hamadian Supergroup (Choubert’s
“trilogie mésocrétacée”, Table 7). As discussed below, we cannot dierentiate the Kem
Kem Group strata in the Kem Kem region on the basis of their rich vertebrate remains.
For this reason alone, it is heuristic to have an inclusive term for the pair of infra-
platform non-marine units under the Late Cenomanian-Turonian platform. e Kem
Kem Group appears to extend across much of central and eastern Morocco north and
south of the Pre-African Trough. In this report, we do not extend Kem Kem Group
correlations to strata west of Morocco, although we anticipate future studies making
correlations to the thinner terrestrial beds in western Algeria (Benyoucef et al. 2015)
and beds farther east across northern Africa.
Gara Sbaa Formation
e Gara Sbaa Formation, with stratotype at the locality Gara Sbaa (Fig. 15, Table 7),
comprises the lower unit of Kem Kem Group rocks in the Kem Kem region of eastern
Morocco. Northernmost exposures are located approximately 30 km south of Erra-
chidia (near Zrigat). e formation is exposed as a relatively narrow band that extends
southeasterly toward Taouz, following the western edge of the Guir Hamada, and then
southwest along the northwestern edge of the Kem Kem Hamada, pinching out ca. 30
km north of Mhamid (Figs 15–17). Much of the outcrop is exposed in isolated patches
or on the anks of ravines, the remainder covered by limestone talus from the resist-
ant Late Cenomanian-Turonian platform that holds the edge of the hamada. Broader
areas of outcrop occur where the escarpment is prominent near Zrigat, Gara Sbaa, and
Iferda N’Ahouar.
e Gara Sbaa Formation rests unconformably on fossiliferous marine Paleozoic
rocks of Silurian, Devonian and Cambrian age (Figs 18, 19), a contact of some relief
that is exposed only in few areas (Figs 12A, 13A, 19). e contact is exposed in sections
at Taouz and Ouzina (Fig. 16), where the formation thickens from approximately 60
m to 100 m, respectively. It is thicker and well exposed at Gara Sbaa, where a ~ 135 m
section is exposed (Fig. 17). Projecting from Paleozoic outcrops nearby, the basalmost
10–20 m of the formation is covered at Gara Sbaa. Maximum thickness of the forma-
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
28
8. Hassi
Zguilma
7. Talidat
Sbaa
6. Gara
Tkout
5. Oum
4. Iferda
N’Ahouar
3. Ouzina
2. Taouz
1. Douira
Figure 15. Generalized lithostratigraphic sections of the Kem Kem Group from Douira in the north to
Hassi Zguilma in the south. Vertical scale bar equals 100 m.
tion, thus, is ~ 150 m in the region of the stratotyope Gara Sbaa, thinning to ~ 60 m
to the northeast at Taouz and ~ 50 m to the south at Hassi Zguilma (Figs 15–17). e
basal contact with bluish Ordovician siltstones is clearly exposed at Ouzina, which is
here designated as the boundary stratotype for the base of the formation. e forma-
tion, often terminating in a cemented sandstone, is conformably overlain by a substan-
tial red mudstone of the Douira Formation (Figs 20, 21). is contact is well exposed
at Gara Sbaa and in other sections.
Lithology. e Gara Sbaa Formation is composed predominantly of red-colored,
ne- and medium-grained sandstone beds. e basal one-quarter of the formation is
characterized by poorly cemented coarse sandstones with minor conglomerate beds.
e basal bed at Tikniouine Bou Tazoult consists of a relatively thin (< 1 m thick) con-
glomerate with sub-rounded pebbles and cobbles derived from the underlying Paleo-
zoic clastics and, rarely, Paleozoic volcanics. A red-colored medium sandstone forms
the basal bed in some areas (e.g., Aferdou N’Chaft). e remainder of the bottom one-
quarter of the formation is predominantly medium-to-ne, poorly sorted sandstone
with rare siltstone and mudstone beds. e sandstone has interstitial mud and some
mac and feldspar clasts. e poorly sorted sandstone is reddish on both weathered
and freshly broken surfaces. Sandstone beds are generally thickly bedded (30–100 cm)
Kem Kem Group of Morocco 29
4. Iferda N’Ahouar
cstsdp
M
M
M
M
Paleozoic
Limestone
x
cstsdp
3. Ouzina
M
M
M
M
M
M
L
x
x
x
cstsd p
Paleozoic
2. Taouz
x
x
x
x
x
x
x
Mudstone
x
x
M
M
cstsd p
1. Douira
Mudstone
M
M
M
M
L
M
M
Limestone
Mudstone
Claystone
Silty mudstone
Siltstone
Sandstone
Cover L
M
x
Soft sediment deformation
Planar cross bedding
Trough cross bedding
Wood
Vertebrate fossils
Vertical burrows
Concretions
Pebbles
Laminated
Mottled
Ripples
Figure 16. Northern lithostratigraphic sections of the Kem Kem Group. Vertical scale bar equals 100 m.
Abbreviations: c clay p pebble sd sand st silt.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
30
Limestone
Mudstone
Claystone
Siltstone
Sandstone
Cover
L
M
x
Soft sediment deformation
Planar cross bedding
Trough cross bedding
Wood
Vertebrate fossils
Vertical burrows
Concretions
Pebbles
Laminated
Mottled
Ripples
Silty mudstone
Lateral accretion set
Lenticular bedding
Footprints
LA
BBlocky
Mud cracks
Gastropods
Cephalopods
Oysters
Bivalves (non-oyster)
SSlicks
8. Hassi Zguilma
cstsdp
mudstone
Silty
Siltstone
mudstone
Silty
LMudstone
LSiltstone
x
x
x
7. Talidat
cstsdp
B
B
M
x
cstsdp
6. Gara Sbaa
B M S
M
B
B M S
L
L
B M
L M
B M S
B M
Siltstone
x
x
x
cstsdp
5. Oum Tkout
LA
x
x
x
x
x
x
x
M
Figure 17. Southern lithostratigraphic sections of the Kem Kem Group. Vertical scale bar equals 100 m.
Abbreviations: c clay p pebble sd sand st silt.
with occasional erosional channel scours up to 1 m deep. Limited in exposure, the
lower one-quarter of the formation did not yield any body or trace fossils.
e remainder of the formation is composed of coarse-to-ne sandstone beds
interspersed with pebble lags. in ne-grained beds and paleosols occur rarely. e
Kem Kem Group of Morocco 31
Figure 18. Outcrop of Paleozoic rocks underlying the Kem Kem Group near Hmar Lakhdad.
sandstones show greater maturity than in the basal beds and are composed almost ex-
clusively of well-sorted, well-rounded quartz grains. e sandstone weathers bu-to or-
ange-pink-red and is typically lighter in color, tan-to-yellow, on freshly broken surfaces.
Bed thickness ranges from thinner beds 0.3 m to 1.5 m thick to major units 2 to
80 m in thickness. icker beds, which occur toward the top of the formation, oc-
casionally preserve lateral accretion surfaces with paleo-relief up to 8 m. Sandstone
bodies typically accrete as tabular beds with a horizontal bottom. Tabular and trough
cross-stratication is common with foresets dipping at 20–25° (Figs 22–25). Cross-
beds frequently exhibit sorting, the coarser beds including coarse to very coarse sand,
granules, and small pebbles. Desiccation cracks and ripple marks indicate intervals of
very shallow water conditions (Fig. 25D, E).
e beds in the upper three-quarters of the formation often show cyclic deposition.
A basal sandstone bed exhibits trough cross-stratication and sometimes thin conglom-
erates. is is followed by tabular cross-stratied beds that indicate channel inll. ese
beds are followed by sandstones rich in yellowish clay and bone fragments that may
indicate incipient soil development. ese cycles comprise the inlling of channels.
Unusual sedimentary structures include disrupted bedding, spherical concre-
tions, and slab-forming carbonate and iron cemented beds. Disrupted bedding (es-
cape structures, sand volcanoes) and overturned cross-bedding (Fig. 25A-C) in some
places suggests thixotropy (liquefaction). Dewatering and slumping on gentle slopes
may have been triggered by earthquakes. Pinkish spherical concretions, with diameters
of 35–150 mm, are common and sometimes are present in cemented aggregations on
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
32
Figure 19. Paleozoic rocks underlying the Kem Kem Group. A Jbel Sdila locality. B Close-up of Paleo-
zoic basement.
bedding surfaces (Figs 26, 27). ese iron-rich concretions, sometimes called ‘kerk-
oubs’ (Cailleux and Soleilhavoup 1976), often, but not always, follow bedding planes.
Carbonate- and iron-cemented beds that are dark brown or even black in color occur
in places at the top of the formation as a resistant ledge.
Kem Kem Group of Morocco 33
Figure 20. e Kem Kem Group at Iferda Timenkherin. A Overview B Close-up view of the boundary
between members at Gara Sbaa: 1 Quaternary aeolian sand 2 Lower member 3 Boundary between the
upper and lower members. Abbreviations: DF Douira Formation GSF Gara Sbaa Formation.
e sedimentary structures described above and the lack of substantial conglom-
erates suggest that the Gara Sbaa Formation records large-scale transport of detrital
material typical of a deltaic river system. Cross-bed orientation in the lower quarter
of the formation strongly favors a northward ow direction parallel to the axis of the
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
34
Figure 21. Limit (arrow) between the Gara Sbaa and Douira Formations.
Kem Kem embayment. e change in sedimentary style in the upper three-quarters of
the formation suggest the inlling of an expansive alluvial basin centered on the low-
gradient Kem Kem ramp.
Paleontology. Vertebrate body fossils most frequently occur as isolated elements
(especially bone fragments, teeth, scales) in conglomeratic deposits characterized by
rip-up clasts and pebbles. Rostral teeth of a large sawsh, Onchopristis numidus, are
often the most common taxon among recovered teeth. Other common fossils include a
wide range of aquatic and terrestrial species including polypterids, lepisosteids, amiids,
bony shes, dipnoans, turtles, crocodyliforms, and isolated teeth of the theropods Spi-
nosaurus and Carcharodontosaurus. e teeth of terrestrial herbivores are conspicuously
rare and only include sauropods. Articulated skeletons are extremely rare and only
include the holotypic partial skeletons of Rebbachisaurus garasbae and Deltadromeus
agilis (Sereno et al. 1996, Wilson and Allain 2015). Nonvertebrate remains are rare
and include unionoid bivalves recovered at Aferdou N’Chaft and Zrigat. Trace fossils
include root traces within rare mudstones, straight, vertical burrows averaging 2 cm in
diameter and tens of centimeters long within cross-bedded sandstones, and borings in
dinosaur bone fragments (Ibrahim et al. 2014a). e borings are curved, unbranched,
tubular traces situated most commonly in the outer portion of weathered bone. ese
may represent the insect ichnotaxon Cubiculum ornatus or another arthropod feeding
Kem Kem Group of Morocco 35
Figure 22. Large-scale primary sedimentary structures. Large sedimentary structures occur occasionally
in the upper parts of the Gara Sbaa Formation and the lower parts of the Douira Formation. In contrast
to the primarily sandstone unit in (A), the lithology of (B) consists of inter-bedded sandstone and ner-
grained beds. Human for scale in each equals 185 cm. e large-scale cross-bedding with good bottomsets
and relatively low angle foresets is consistent with small Gilbert-type delta fronts. Alternatively, they could
represent large point bar deposition with the diering lithologies of B as inclined heterolithic stratication.
on subaerially exposed bone (Ibrahim et al. 2014a). alassinoides-like burrows occur
in a thin limestone in the Gara Sbaa Formation at Zrigat.
Douira Formation
e Douira Formation, with stratotype at the locality Douira (Fig. 16, Table 2), com-
prises the upper unit of Kem Kem Group rocks in the Kem Kem region of eastern Mo-
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
36
Figure 23. Primary sedimentary structures in the Gara Sbaa Formation. A Linear cross-bedding at Gara
Sbaa B Trough cross-bedding at Aferdou N’Chaft C Shallow channel cross-bedding (arrow) at Gara Sbaa
D Tabular cross-bedding from unidirectional ow at Gara Sbaa E Large-scale cross-bedding at Gara Sbaa
F Trough cross-bedding at Aferdou N’Chaft.
Kem Kem Group of Morocco 37
Figure 24. Tabular cross-bedding in the Gara Sbaa Formation. A Weathering of common tabular cross-
beds B Close-up view of tabular cross-beds.
rocco. As with the underlying Gara Sbaa Formation, the northernmost outcrop is lo-
cated approximately 30 km south of Errachidia (near Zrigat). e formation is exposed
as a relatively narrow outcrop that extends southeasterly toward Taouz, following the
western edge of the Guir Hamada, and then southwest along the western edge of the
Kem Kem Hamada, pinching out ca. 30 km north of Mhamid. Much of the outcrop
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
38
Figure 25. Sediment deformation and surface structures in the Gara Sbaa Formation at Gara Sbaa.
ALarge-scale overturned cross-bedding B Cross-section of overturned cross-bedding. C Surface view of
overturned cross-bedding D Ripple marks E Desiccation cracks.
is exposed in isolated patches or on the anks of ravines, the remainder covered by
limestone talus from the overlying Late Cenomanian-Turonian platform that holds
the edge of the Hamada (Figs 28, 29). Areas of outcrop are restricted and sometimes
vertical, given the softness of the formation underlying the resistant carbonate escarp-
ment. e Douira locality is well exposed and particularly rich in micro-vertebrate
remains. Work in this section resulted in the discovery of a number of the shark teeth
that established a Cenomanian age for Kem Kem Group strata (Sereno et al. 1996).
Kem Kem Group of Morocco 39
Figure 26. Enigmatic concretions (‘kerkoubs’) in the Gara Sbaa Formation. A In cross-stratied sand-
stones at Gara Sbaa B In ow direction near Boumerade C With linear sedimentary structures at Gara
Sbaa D With great size variation at Gara Sbaa E In tabular cross-bedding at Gara Sbaa F In high density.
e formation is thickest at Douira, where a 124-m section is exposed. Maximum
thickness of this formation is located more distal (north) than the thickest part of the
underlying, progradational Gara Sbaa Formation. Like the Gara Sbaa Formation, it
thins to the east to 52 m at Taouz and to the south to approximately 100 m at Oum
Tkout and Gara Sbaa and to 46 m farther south at Hassi Zguilma (Figs 16, 17).
e Douira Formation rests conformably on the Gara Sbaa Formation, a contact that
shows very little relief. e basal bed of the Douira Formation is an easily recognizable
reddish mudstone averaging ~ 1 m in thickness. is bed is always the rst substantial
mudstone in Kem Kem Group strata (Fig. 21). e uniform presence of this ne-
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
40
Figure 27. Close-up of ‘kerkoubs’ showing granular surface texture. Scale bar equals 1 cm.
grained bed over a broad geographic region suggests there was a transgressive pulse of
some sort that altered the sedimentary regime for the region. e upper boundary of
the Douira Formation, like the lower boundary, shows only minor relief, and is marked
by a massive fossiliferous limestone, the basal unit of the overlying Akrabou Forma-
tion. e last sediments of the Douira Formation are typically green or gray claystone
or mudstone. In northern sections of the Douira Formation, a few thin-bedded marl
or limestone units occur some meters below the massive limestone of the Akrabou
Formation. ese are recorded in the section at Ouzina and become more substantial
and spaced in the more distal (north) section at Douira, the rst located some 75 m
beneath the boundary carbonate (Fig. 16).
Lithology. e Douira Formation is ner-grained and has a greater variety of
rock types than the Gara Sbaa Formation. It consists of ning-upwards, coarse-to-ne
grained sandstones intercalated with siltstones, variegated mudstones, and occasional
thin gypsiferous evaporites (Fig. 17). Like the Gara Sbaa Formation, the Douira For-
mation nes upward, and red-hued rocks predominate. Sandstones dominate the low-
er portion, whereas mudstone, claystone and ledge-forming siltstones and ne sand-
stones dominate the upper portion. Non-sandstone lithologies, which are rare in the
Gara Sbaa Formation, comprise approximately two-thirds of the Douira Formation.
Rock types include mudstones (64%), lesser amounts of sandstone (25%) and siltstone
(10%), and other lithologies (1%) such as rare thin-bedded gastropod-rich limestones.
In measured sections, the volume of silt and ner lithologies ranges from 50% at Gara
Sbaa to 84% farther distally (north) on the delta at Iferda N’Ahouar.
Kem Kem Group of Morocco 41
Figure 28. Exposures of the Douira Formation and underlying sandstones. A Outcrop at Iferda
N’Ahouar B Outcrop at Tikniouine Bou Tazoult. Abbreviations: 1 Limestone platform 2 Douira Forma-
tion 3 Sandstone of the Gara Sbaa Formation.
Five sandstone facies occur within the Douira Formation. Some 60% of the sand-
stones are ning-up beds that begin with a coarse-grained sandstone that is poorly
sorted with pebble-sized lithics. is basal bed contains cobble-to-pebble-sized clay
balls, mud rip-up clasts, bone fragments and isolated teeth. e rest of the facies is
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
42
Figure 29. Satellite image at Gara Sbaa (Photo credit: Google Imagerie, 2010 Digital Globe). Scale bar
equals 500 m. Abbreviations: 1 Kem Kem Group 2 Overlying limestone platform of the Akerbous Forma-
tion (Cenomanian-Turonian).
composed of ne sandstone or siltstone often characterized by trough and planar large-
scale cross-bedding. ese beds, which range from 5 to 50 cm in thickness, are also
characterized by mud drapes, aser bedding, vertical burrows and soft-sediment defor-
mation. Rock colors include yellow, orange, red, and tan, with yellow beds sometimes
weathering red.
A second sandstone facies comprising ca. 23% of sandstones consists of stacks
of cross-bedded, ne- to medium-grained beds with sharp lower and upper contacts.
Cross-bedding includes both trough and planar varieties commonly 10–20 cm deep,
with a maximum depth of 40 cm. is facies is well-sorted, ne-grained, and bu, red,
and occasionally white in color.
A third sandstone facies comprising ca. 16% of sandstones are red to orange, ne-
grained beds interbedded with siltstones and mudstones. ese sandstones, commonly
5–50 cm thick, often have ripple-scale cross-bedding, laminations, and mud drapes
and preserve dinosaur footprints and burrows (Belvedere et al. 2013, Ibrahim et al.
Kem Kem Group of Morocco 43
Figure 30. Primary sedimentary structures in the Douira Formation. A Fine-grained interbedding of the
upper portion of the Douira Formation underlying the Cenomanian-Turonian limestone B Fine-grained
mudrock with vertical paleosol zonation and root traces.
2014a). Typically this facies occurs with thinner overall sequences, usually less than
50 cm in thickness. However, some meters-thick inclined heterolithic stratications
were observed outside of the measured sections. Rarer sandstone facies include massive,
medium-grained, orange to red-orange sandstones that are 2 m in thickness or less and
yellow units. Finally, there are coarsening-up sequences, from one to a few meters thick.
Siltstones and very ne sandstones are persistent but uncommon in the Douira
Formation, representing only ca. 10% of the entire stratigraphic thickness. Often these
lithologies occur as units less than 50 cm thick, with bed thicknesses more commonly
between 5 and 20 cm. Color may vary from bluish white to red-orange. Small-scale
cross-bedding, laminae, and nonvertebrate traces are abundant. Occasionally these
units also preserve mud-cracks, dinosaur footprints, mud drapes, and aser bedding.
Soft sediment deformation is rare.
Mudstones and claystones dominate the Douira Formation. In the complete and
well-exposed sections, these ne-grained units represent an average of 64% of the
stratigraphic thickness. Mudstones occur in four facies: reddish-brown massively bed-
ded units (38%), interbedded mudstones (40%), minor laminated beds, and green
claystone. Red-brown to red mudstones, which are common in the lower portion of
the formation, are characterized by mottling, slickensides, and blocky to crumbly tex-
tures. Calcitic nodules, gypsum crystals, root traces, and burrows are rare.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
44
Interbedded mudstone with claystone is the dominant facies of the upper half of
the Douira Formation (Fig. 30). is facies typically shows a mix of diuse bedding
and gradational contacts together with sharper boundaries. Color of these mudstones
includes red-brown, purple, red, green, and tan. Mottling and slickensides occur com-
monly. ese lithologies exhibit occasional root traces, and rare four-sided mudcracks
and are variably calcareous, with massive blocky and crumbly textures.
Laminated mudstones, best developed at Oum Tkout (Figs 17, 31) and composed
mainly of illite, are a minor component of the lower portion of the formation. ey
are variable in color (red-brown, tan, gray, white). At Oum Tkout, this facies represents
a pond setting that preserved an array of plants, insects, decapods, elasmobranchs,
and actinopterygians (e.g., Dutheil 1999a, 1999b). e last minor mudstone facies is
green claystone, which occurs just below the massive limestone of the Cenomanian-
Turonian transgression.
Limestones and marls, which comprise a very small fraction (< 1%) of the Doui-
ra Formation consist of blueish gray-to-white, ledge-forming beds less than 50 cm
thick with substantial clay and silt. is facies occurs in the upper 20 m of the
Ouzina section. At Douira calcareous beds are more common and comprise 7% of
the section. Beds 20–30 cm in thickness occur inter-bedded with mudstones and
claystones. One very thin (1 cm) gypsum horizon, in addition, occurs just below
a calcareous mudstone. is facies and more signicant evaporite deposits become
much more common in beds of the Kem Kem Group outside the Kem Kem Hamada
(Table 7).
Paleontology. Fossils are less abundant than in the Gara Sbaa Formation, although
the same range of vertebrate taxa are recorded. Associated dinosaur remains from the
Douira Formation include the cranium of Carcharodontosaurus and partial skeleton of
Spinosaurus (Sereno et al. 1996, Ibrahim et al. 2014b).
Trace fossils are common in many horizons. e ner-grained deposits and soil
development facilitated footprint and other trace fossil preservation. Horizons with
vertebrate tracks occur throughout the formation from within a few meters of its
base to within 6 or 7 m of the overlying limestone platform (Ibrahim et al. 2014a).
ey are most common in a “footprint zone” from 30 to 10 m below the top of the
Douira Formation (Sereno et al. 1996: g. 1C). Tracks pertain to medium- and
large-sized theropods and, much less frequently, large-sized ornithopods and sauro-
pods (Sereno et al. 1996, Belvedere et al. 2013, Ibrahim et al. 2014a). Tracks occur
as impressions and natural casts, the latter the more common and usually occurring
in the rare siltstone and sandstone beds. Some are particularly deep and show stria-
tions from the motion of the toes through the soft sediment. Nonvertebrate traces
include Conichnus, a possible resting trace of a sea-anemone, Scolicia, a gastropod
trail, worm-like Beaconites horizontal meniscate burrows, and short, sub-vertical
burrows that appear to be dwelling traces of a crustacean (Ibrahim et al. 2014a).
ese last two trace types occur together in abundance and may represent the activ-
ity of detritivores on a tidal at.
Kem Kem Group of Morocco 45
Paleogeography and paleoenvironments
Cenomanian paleogeography. Currently, there are no major river drainages from
northern Africa into the Mediterranean west of the Nile River. In Morocco uplift
during the Cenozoic created the Alpine Belt to the north of the Preafrican Trough,
cutting o drainage to the Mediterranean. In Cretaceous time, however, a major drain-
age existed between eastern Morocco and western Algeria that owed northward into
the Tethys Ocean (Delfaud and Zellouf 1995). Our paleocurrent measurements and
those of Cavin et al. (2010) strongly support this drainage direction (contra Russell
1996). e Morocco-Algeria border region, and in particular the Kem Kem embay-
ment, would have provided a ramp for northward drainage from the western Sahara
(Fig. 32). Interconnected basins along that trough may also have allowed secondary
drainage from the Kem Kem embayment to the west into the central Atlantic Ocean
(Delfaud and Zellouf 1995, Essafraoui et al. 2015). e Kem Kem embayment and
Kem Kem Group formations, thus, may be envisioned as the headland of a vast river
system feeding north to a prograding delta (Fig. 33).
An evolving delta. e Gara Sbaa and Douira formations of the Kem Kem Group
in Morocco have long been envisioned as deltaic in general character (Sereno et al.
1996). Sedimentary structures of the Gara Sbaa Formation were deposited by an anas-
tomosing uvial system, starting with conglomeratic beds over eroded Paleozoic strata
(Fig. 32, stages 1, 2). Fining-upward sediments and sediment cycles characterize the
Figure 31. Oum Tkout locality where quarrying has recovered an abundance of exceptionally preserved
aquatic vertebrates and invertebrates in a still-water setting.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
46
Figure 32. Schematic paleoenvironmental stages depicting the Kem Kem region during the Cretaceous.
Stages: 1 wide rivers 2 large river systems with substantial sandbanks 3 deltaic conditions 4 rise of the
limestone platform.
Kem Kem Group of Morocco 47
5
6
BA
1
3
2
4
100 km
10
o
0
o
50
o
35o
30o
Figure 33. Schematic geography of the major rivers systems in northern and western Africa during the
Late Cretaceous (modied from Zellouf and Delfaud 1986, Delfaud 1986, Dutheil 2000). A Kem Kem
river system with ow to the north B Kem Kem, paleo-Nile and paleo-Niger river systems. Abbreviations:
1 Meseta 2 Anti-Atlas 3 Ougarta 4 Kem Kem river and delta 5 Paleo-Nile river and delta 6 Paleo-Niger
river and delta.
Gara Sbaa and Douira formations. Prograding delta sediments of the upper Gara Sbaa
and lower Douira Formation give way and coastal deposits and sabkas in the upper part
of the Douira Formation, prior to inundation by a marine transgression (Guiraud et al.
2005, Figs 34, 35). e Gara Sbaa and Douira formations, thus, capture the transition,
likely in the Early and Middle Cenomanian, from uvial to deltaic to lower-energy
coastal, pond and sabkha paleoenvironments. Coastal mangrove deposits, recorded in
the likely coeval Bahariya Formation in Egypt (Smith et al. 2001), are not present in
the sediments of the Kem Kem embayment.
During deposition of the Gara Sbaa and Douira formations as well as other Kem
Kem Group formations recognized to date (Table 7), marine inuence increases, sedi-
mentary gradient decreases, and lower energy paleoenvironments predominate. e
vertebrate fauna, as best as can be determined from transported fossils, does not change
appreciably during this interval. Modern analogs for Kem Kem Group beds in Mo-
rocco must include a large-scale river system coursing through arid habitats to a pro-
grading delta within reach of a sea or ocean. On Africa the best present-day analog is
the Niger delta (Reijers et al. 1997).
Gara Sbaa sediments and paleoenvironments. e conglomeratic components,
locally derived clasts, and mix of smaller sandstones indicates within-basin deposition
via small-scale uvial systems at the base of the Gara Sbaa Formation (Fig. 32, stage 1).
e increase in bed thickness and larger-scale cross-bedding of overlying sandstones in-
dicate broader and deeper uvial channels (Fig. 32, stage 2). e rarity of mudstones,
the increased lateral extent of sandstone bodies, and their more mature composition
indicate reduced accommodation space and lateral redeposition by channels of earlier
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
48
Figure 34. Geology and paleontology at the boundary between the Douira Formation and the Gara Sbaa
Member of the Cenomanian-Turonian limestone at Gara Sbaa. A Marly limestone separating the Kem
Kem Group from the Cenomanian-Turonian limestone B Close-up of a basal limestone unit in the Gara
Sbaa Member C Oyster fossil in situ in the basal limestone D Deep-bodied teleost (Diplomystus sp.) from
the Gara Sbaa Member of the Cenomanian-Turonian limestone E Long-bodied teleost (Agoultichthys
chattertoni) showing preservation of soft n structures from the Gara Sbaa Member (Murray and Wilson
2009) D and E from Martill et al. (2011). Scale bars equal 1 cm in D and 2 cm in E.
channel and oodplain deposits. Reworking may have generated the conglomeratic
beds with rip-up clasts and pebbles that contain vertebrate teeth and bone (Fig. 36;
Rogers 1993).
Several possible indicators of tidal inuence occur within the upper portion of the
Gara Sbaa Formation through the Douira Formation. ese include mud drapes, aser
and lenticular bedding and inclined heterolithic strata. e maturity of the sandstones
within this stratigraphic interval may also reect tidal inuence (Tucker 2011). e
Kem Kem Group of Morocco 49
Figure 35. Fissile weathering of the Cenomanian-Turonian limestone platform.
larger, possibly tidally inuenced, channels of the upper portion of the Gara Sbaa For-
mation indicate deltaic environments. Large-scale cross-bedding with depths exceed-
ing 6 m may indicate progradation of the delta front (Fig. 24).
Douira sediments and paleoenvironments. Evidence favoring deltaic prograda-
tion is limited to the lowermost portion of the Douira Formation. As the transgression
continued, the entire Kem Kem uvial system appears to have stalled. Grain size and
channel forms diminish up-section. In the deeper northern region of the ramp, evapo-
rites and limestones become more common as clastic input waned. e lowered gradi-
ent of the Douira Formation largely consists of a variety of low-energy depositional
environments under tidal, and later more fully marine, inuence.
ese depositional settings involve smaller uvial channels, oodplains with some
incipient paleosol development with root traces, crevasse splay deposits important for
the preservation of dinosaur tracks, and a freshwater pond deposit at Oum Tkout with
decapods and small-bodied bony shes (Fig. 32, stage 3; Dutheil 1999a). Marginal
marine environments also occur within the uppermost Douira Formation prior to
the deposition of the limestone platform of the Akrabou Formation (Fig. 32, stage 4).
ese environments consist of shallow water tidal ats represented by mudstones with
abundant simple tubular dwelling traces or Conichnus, possible sea-anemone resting
traces (Ibrahim et al. 2014a). In some sections, green claystones and marls occur at the
top of the formation transitional to the overlying limestone. Arid to semi-arid condi-
tions were common in low-latitude northern Africa during the Cenomanian (Scotese
2002), generating intervals of sabkha-like conditions.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
50
Figure 36. Pebble and fossil lag deposits in the Kem Kem Group. A Common pebble lag deposit com-
posed of two beds B Abraded vertebrate remains including a partial sawsh rostral tooth (Onchopristus
numidus). Scale bars equal 60 cm (10 cm intervals) in A and 5 cm in B.
Brackish water. e Kem Kem delta was dominated by rapidly moving fresh-
water/brackish (lotic) paleoenvironments with water owing toward the open ocean,
as opposed to the much rarer still water (lentic) paleoenvironments represented by
Kem Kem Group of Morocco 51
ponds. e Oum Tkout locality, interpreted here as a pond paleoenvironment, pre-
serves small-bodied (< 10 cm) osteichthyans, such as polypterids and osteoglossiforms.
Extant representatives live either in exclusively or predominantly freshwater habitats.
Within the much more common lotic paleoenvironments, the question arises as to
whether these were predominantly freshwater, brackish or fully marine. Cartilaginous and
bony sh can provide evidence regarding the nature of the water systems. Available evi-
dence points to both freshwater and brackish conditions. Dipnoan tooth plates are com-
mon and support freshwater conditions, as all extant dipnoans occupy freshwater habitats.
A diverse assemblage of lamnifom shark teeth, however, suggests that brackish
conditions were common. Although the batoid Onchopristis dunklei (McNulty and
Slaughter 1962) is a coastal marine species, it is plausible that O. numidus was adapted
to freshwater, as the taxon also occurs in Cenomanian deposits in Niger (Lapparent
1953, DBD pers. obs.) at a considerable distance from any maritime coast. Some ex-
tant batoids, such as the South American stingray Potamotrygon reside exclusively in
freshwater habitats (Stauch and Blanc 1962) but can adjust if subjected to saline condi-
tions (orson 1970). e same argument applies to the large Kem Kem coelacanth
Axelrodichthys lavocati (previously referred to Mawsonia, Carnier Fragoso et al. 2019),
which has also been found in freshwater deposits in Niger and Brazil.
In summary, the Kem Kem uvial system shows evidence of both freshwater, and
brackish conditions. Up section, in the upper portion of the Gara Sbaa Formation and the
Douira Formation, tidal indicators suggest brackish conditions may have become stronger.
Hothouse climate. Hothouse conditions likely prevailed during deposition of
Kem Kem Group rocks in much of the area now occupied by the Sahara, with harsh
seasonality, arid conditions and strong convective storms predominating (Russell and
Paesler 2003, Holz 2015). e Earth’s climate is now widely understood as oscillat-
ing on a scale of millions of years between icehouse, greenhouse and hothouse states
(Fischer 1982, Kidder and Worsley 2010, 2012, Wendler and Wendler 2016, Hu et
al. 2017). During the Cenomanian, sea levels reached their maximum during the Cre-
taceous (Holz 2015), sea surface temperatures were very elevated (Boucot and Gray
2001), and temperate forests grew within the polar circles (e.g., Herman and Spicer
1996, Falcon-Lang et al. 2001).
Age
e ages of the Gara Sbaa and Douira formations are based on relative dating of a suite
of nine elasmobranch genera collected from both the Gara Sbaa and Douira formations
(Sereno et al. 1996). e overlying Akrabou Formation oers additional relative dates
based on marine nonvertebrates, providing a young age limit for the underlying Kem
Kem Group sediments (Ferrandini et al. 1985, Garassino et al. 2008, Martill et al. 2011a).
Nine elasmobranchs were collected in the Gara Sbaa and Douira formations (Ser-
eno et al. 1996). Seven of these (and three theropod genera, Carcharodontosaurus, Spi-
nosaurus, Deltadromeus) are shared with the Bahariya Formation in Egypt (Fig. 1),
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
52
also regarded as Cenomanian in age. One of these elasmobranch species (Haimrichia
amonensis Cappetta & Case, 1975) has a broad circum-Mediterranean distribution
and has been found elsewhere in Africa and Asia in Cenomanian-age strata (Vullo et
al. 2016). No elasmobranch genera have been recovered with an age range restricted to
the Albian or earlier. e evidence from elasmobranchs, thus, suggests a Cenomanian
age for both the Gara Sbaa and Douira formations.
e Gara Sbaa, Douira, and Akrabou formations comprise a single, stepped trans-
gressive sequence recording a succession of uvial, deltaic, low-energy coastal environ-
ments, to nally an oshore carbonate platform. e formations do not show any major
erosional or hiatal surfaces or incised channels that would argue for a contained regres-
sive phase. Instead, marine inuence increases steadily up-section to a comformable
and gradational contact with the overlying Akrabou Formation. e contact between
the Douira and Akrabou formations is conformable and shows almost no topography,
as observed at many places along the Guir and Kem Kem Hamadas. A thin laminated
clay layer a few centimeters thick is often present in well exposed sections at the top of
the Douira Formation immediately below the rst carbonate layers of the platform. is
suggests that inundation and development of an initial coastal platform occurred swiftly
without a signicant temporal hiatus sometime in the Late Cenomanian.
is transgression corresponds in general to rising eustatic sea levels during the
Cenomanian, although rising sea levels began during the Albian (Holz 2015). e
depositional history of the Kem Kem Group appears to represent a single transgressive
sequence leading up to this sea-level maximum. Global sea-level curves would thus
suggest that the Kem Kem Formation is Cenomanian in age with a maximum age of
approximately 98 or 97 Ma (Haq et al. 1987, Ogg et al. 2016) and a total duration of
3.5 to 4.5 Ma. e uniformity of the Kem Kem vertebrate fauna from the two forma-
tions is consistent with this relatively short temporal span.
e age of the boundary between the Gara Sbaa and Douira formations is an open
question. at boundary is easily distinguished along the length of the Kem Kem re-
gion. It also appears to register as a regional event that occurs in comparable strata to
the north and east (Table 7). is boundary, which separates a sandy deltaic unit from
a predominantly gypsiferous mud, is linked to an abrupt rise of eustatic sea level. Along
the Atlantic coast, there are many observable sea level cycles in sections across the
Cenomanian, but these cannot be correlated westward by continuous outcrop to Kem
Kem Group strata in central and eastern Morocco (Essafraoui et al. 2015). A marked
sea level rise during the Cenomanian, nevertheless, is recognized above all others glob-
ally and in the well-studied Tarfaya Basin on the Atlantic coast of Morocco. Called the
“Mid Cenomanian Event”, it has been dated to approximately 96.0 Ma (Kuhnt et al.
2009, Holz 2015). Here we suggest that this global rise in sea level may be linked to the
distinctive shift to ner-grained sedimentation observed in Kem Kem Group rocks.
Regarding the age of the Akrabou Formation, several studies of the carbonate
platform in central Morocco have described the range of ammonites and many other
nonvertebrates that correspond with two major transgressive events. e rst trans-
gression, located at the base of the Akrabou Formation, has yielded a diverse ora and
Kem Kem Group of Morocco 53
nonvertebrate (limulid, crustacean, insect), elasmobranch and actinopterygian fauna
from localities atop buttes near Gara Sbaa with an estimated age near the end of the
Cenomanian (Garassino et al. 2008, Martill et al. 2011a, Vullo et al. 2016, Lamsdell
et al. 2020). At approximately 94.5 Ma, eustatic sea level swiftly rose to inundate near-
shore environments across northern Africa and Europe (Voigt et al. 2006, Kuhnt et
al. 2009, Essafraoui et al. 2015). e second transgression occurs within the platform
sequence, when rising sea levels generated benthic conditions across much of northern
Africa at the Cenomanian-Turonian boundary at approximately 93.6 Ma (Ferrandini
et al. 1985, Parente et al. 2008).
e dates discussed above can be assembled into a chronology for Hamadian Su-
pergroup rocks in central and eastern Morocco (Table 7). Deposition may have com-
menced on a prograding delta in the latest Albian or earliest Cenomanian approxi-
mately 100.0 to 99.0 Ma. Sedimentation shifted to ner-grained coastal sedimenta-
tion tied to the Mid Cenomanian Event around 96.0 Ma and later underwent rapid
inundation and development of a carbonate platform at approximately 94.5 Ma. e
platform waters deepened near the Cenomanian-Turonian boundary at approximate-
ly 93.6 Ma, with marine conditions persisting until the Middle Turonian regression
around 92.0 Ma. e chronology sketched above suggests that the fauna we review in
the pages that follow probably comes from a temporal interval within the Cenomanian
of less than 5 Ma from approximately 100 to 95 Ma.
Taphonomy
Preservation. Five modes of preservation are possible to distinguish when fossils are
found in situ in the Gara Sbaa and Douira formations: (mode 1) channel lags of con-
centrated resistant material (teeth, vertebrae, etc.); (mode 2) microsite lags of concen-
trated small material (especially teeth); (mode 3) isolated elements (bone fragments or
teeth); (mode 4) associated remains (partial vertebrate skulls or skeletons); and (mode
5) a pond deposit (plants, small-bodied teleost sh and decapods).
Most body fossils in the Kem Kem region were probably preserved in modes 1–3
and are discovered as isolated, fragmentary pieces weathered out from sandstones in
both formations. Associated or articulated vertebrate specimens (mode 4) are very rare
(Fig. 37A). Fossils tend to collect in erosional lag horizons with other hard rock debris
(Figs 36B, 38, 39), and so their precise mode of preservation is dicult to ascertain.
Robust fossils, such as teeth or vertebral processes, predominate (Fig. 38C), and these
are frequently broken and abraded to some degree from transport (Fig. 38B, D). Some
small specimens show no discernable indications of transport (Fig. 38E, F), although
their size may have reduced the evidence of abrasion.
e best preserved large-bodied vertebrates are isolated specimens of four dinosaurs
from dierent locations, two in the Gara Sbaa Formation and two in the Douira For-
mation. e partial skeleton of Rebbachisaurus garasbae appears to be the only associ-
ated large vertebrate specimen recovered in the Gara Sbaa Formation. Its stratigraphic
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
54
Figure 37. Taphonomy of Kem Kem vertebrate bone and teeth. A Articulated sh vertebrae in cross-
section at Boumerade. B Cf. Spinosaurus tooth (arrow; FSAC-KK 201) adjacent to rounded pebbles C
Concentration of broken bone fragments (<10 cm) D Partial archosaur tooth (MNHN-MRS 1280).
position and locality are based on the historical records of R. Lavocat (Wilson and Al-
lain 2015: g. 2). Also in the Gara Sbaa Formation at the locality Aferdou N’Chaft, a
partial skeleton of Deltadromeus agilis was discovered weathering from a coarse-grained
sandstone. e skeleton was preserved largely intact, as shown by articulated right and
left shoulder girdles and forelimbs, right and left pedes and a section of caudal verte-
brae and chevrons. It may have been buried suddenly in a channel deposit, judging
from the coarse-grained matrix. In the Douira Formation, a partially articulated cra-
nium of Carcharodontosaurus saharicus was discovered weathering from a ne-grained
sandstone blu several km distant attributed to the same locality. e braincase and
several complete cranial bones were preserved including a pair of nasals close to one
another and one maxilla with teeth preserved in most of the alveoli. Finally, a partial
skeleton of Spinosaurus aegyptiacus was found near Zrigat in the northern exposures
of the Kem Kem region. From the preserved position of some adjacent bones, it also
appears to have been at least partially articulated. Inspection of the site of collection
by several of us conrmed its origin in the Douira Formation and that it was preserved
in isolation. Given their partial articulation, these four dinosaur specimens could not
have been transported signicantly before nal burial.
e most complete fossils are from a singular pond deposit, Oum Tkout (mode
5), discovered in 1995 and revisited several times in the ensuing years (Dutheil
Kem Kem Group of Morocco 55
Figure 38. Taphonomy of Kem Kem vertebrate bone and teeth. A Isolated theropod quadrate (‘valley
near Boumerade’ locality) B Fragmentary archosaur teeth (Gara Sbaa) C Cf. Spinosaurus vertebral zyga-
pophysis (Gara Sbaa) D Abraded sawsh (Onchopristis numidus) rostral tooth E Isolated mixed sample of
small (<1 cm) fossil vertebrates (Boumerade) F Lungsh toothplate (Boumerade). Abbreviations: 1 Turtle
carapace fragment, 2 Fish vertebra, 3 Calcied rostral cartilage of Onchopristis numidus.
1999b). Fossils are recovered by quarrying and splitting small blocks of the ne-
grained pond deposit. e locality contains small-bodied teleost shes, prawns,
macruran decapods and other soft-bodied nonvertebrates (Fig. 40). e fossils are
not concentrated in a single layer or oriented in any particular direction. e rarity
of broken specimens suggests that bottom feeding on the remains of decapods and
actinopterygians may not have been common. Plant debris is common. e light
color of the illite clays that form the majority of the pond mud suggests that anoxia
was not a prevalent condition.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
56
Figure 39. Surface and in situ collecting. A Surface collecting at Gara Sbaa B Collecting in situ fossils
at Boumerade.
A number of bone elements preserve large numbers of borings (Ibrahim et al.
2014a), providing evidence of unrecorded soft-bodied nonvertebrate diversity (Fig.
41). ese borings may have been made by insect larvae similar to those of the carrion
beetle, Osteocallis mandibulus. e borings together with weather-induced cracking
suggest that some bones were subaerially exposed for signicant time prior to transport
and burial (Roberts et al. 2007, Ibrahim et al. 2014a, g. 3c).
Kem Kem Group of Morocco 57
Figure 40. Taphonomy at Oum Tkout. A Indeterminate paraclupeid sh with mineralized muscles
(white) B Soft tissue (muscle) preservation under high magnication C Complete decapod (UCRC
PNV2). Scale bars equal 5 mm in A, 10 μm in B, 3 cm in C.
Nearly all specimens, except those in the singular pond deposit, are preserved in
sandstone varying in grain size and degree of silicate cementation; the mudstones com-
posing portions of the Douira Formation appear to be barren. Poorly cemented sand-
stone is the most common matrix, which is easily removed (Fig. 42A). Patches of more
strongly cemented sediment occur (Fig. 42B), and some specimens have a thin hema-
titic layer adhering to bone surfaces (e.g., the cranium of Carcharodontosaurus). e
matrix varies in color from yellow or beige to orange, pink and dark red (Fig. 42C).
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
58
Figure 41. Invertebrate boring structures in dinosaur bone. A Large bone piece showing local concentra-
tion of burrows (MNHN-MRS 1568) B Close-up view of two burrows on large bone piece C Burrows of
diverse diameter (UCRC I1). Scale bars equal 5 cm in A and 3 cm in C.
Similarly, the fossils exhibit a wide range of colors, although orange and red-brown are
most common, with teeth commonly a darker color (Fig. 43). Some localities yield
fossils of a particular color. Specimens from the Kouah Trick locality collected in the
1950s by R. Lavocat are very dark (Fig. 43B). Specimens from Douira, on the other
hand, are often almost white or cream (Fig. 43A). In general, matrix and fossil color is
highly variable and cannot be used to condently identify place of origin.
Completeness. Quantitative logging of isolated specimens collected from several
localities in 2008 shows that the majority (~75%) are too incomplete to estimate the
percentage of missing bone. Of the remaining more complete specimens, more than
half are less than 50% complete. At one locality, Aferdou N’Chaft, approximately
half of the collected specimens are nearly complete, although this may be an artifact
of small sample size. Clearly most specimens found in the Kem Kem Group are very
fragmentary.
e prevalence of breakage among fossils suggests that they were deposited in a
relatively high-energy environment and either reworked or transported a considerable
distance. Bone breakage, however, does not appear to be a good proxy for distance of
uvial transport (Behrensmeyer 1991). Insect-boring of bones suggests that some ter-
restrial vertebrates were exposed subaerially before transport and burial.
Abrasion. Most of the fossils can be assigned to abrasion category 2 of Anderson
et al. (2007, Table 3). Relatively few are highly abraded (Fig. 44A). At Boumerade,
Kem Kem Group of Morocco 59
Figure 42. Sedimentary matrix associated with Kem Kem fossils. A Well-sorted, ne-grained sandstone
on vertebrate bone (Gara Sbaa) B More oxidized coarse-grained matrix with the base of a rostral tooth
of Onchopristis numidus (“valley near Boumerade”) C Moderately-cemented, red-colored matrix on an
isolated archosaur bone (MNHN, unnumbered). Scale bars equal 3 cm in A, 2 cm in B, 5 cm in C.
“Valley near Boumerade”, and Aferdou N’Chaft, abrasion is minimal (Figs 45A, B,
46B). At Gara Sbaa a greater range of abrasion is present (categories 1–3, Fig. 45B).
Systematic variation in the degree of abrasion between localities may indicate dier-
ences in the distance of uvial transport prior to burial.
Bones, however, can travel long distances without accumulating signs of abrasion
(Behrensmeyer 1982, 1991). Other confounding factors in the interpretation of abra-
sion include the potential for reworking of sandstone deposits within the Gara Sbaa
and Douira formations. e time that fossil material has been subject to subaerial
weathering in lag deposits prior to collection may represent another potentially con-
founding factor when considering breakage and abrasion.
Specimen size. Although Kem Kem fossils vary across a wide size range from < 1
cm to 2 m (Fig. 47), the vast majority of specimens measure less than 10 cm in length
(Fig. 48). Gara Sbaa provides the best estimate of the range in specimen size, given the
large number of fossils collected (Fig. 48B). Specimens collected in ner-grained sedi-
ment at Boumerade and the “Valley near Boumerade” tend to be smaller, the largest
rarely exceeding 4 cm (Figs 48A, 49B). Aferdou N’Chaft and Iferda N’Ahouar locali-
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
60
Figure 43. Color and size variation in Kem Kem vertebrate fossils. A eropod distal quadrate (likely
from Douira) B Archosaur bone and scute fragments (collected by R. Lavocat, Kouah Trick) C ero-
pod left scapula (MPDM 40, unknown locality) D Cf. Rebbachisaurus partial dorsal vertebra (NMC
50844, unknown locality) E Small and medium-sized fossil fragments (UCRC unnumbered) F Sieved
microfossils (UCRC unnumbered). Scale bars equal 5 cm in A and B, 10 cm in C, 20 cm in D, 5 cm
in E, 3 cm in F.
ties seem to have preserved a greater number of larger specimens (Figs 48B, 49A). e
size dierential between these localities may reect variance in the hydrodynamics of
the deposits. Somewhat larger specimens would be expected to be transported and
buried in the higher-energy deposits of the Gara Sbaa Formation. It must be noted,
however, that specimens eroding from the Douira Formation may well accumulate in
lag deposits on the underlying outcrop of the Gara Sbaa Formation. As the majority of
Kem Kem Group of Morocco 61
01234
50
150
250
350
450
B
01234
200
600
A
Figure 44. Abrasion of Kem Kem fossils (FSAC-KK collection). A All localities B Gara Sbaa. X-axis is
the abrasion index (0-4; see Table 3); Y-axis is the number of specimens. Specimen counts in A: 0 707 1
1207 2 647 3 439 4 195. Specimen counts in B: 0 158 1 433 2 396 3 330 4 138.
01234
10
30
50
70
90
B
01234
100
300
700
A
500
Figure 45. Abrasion of Kem Kem fossils (FSAC-KK collection). A Boumerade. B Aferdou N’Chaft. X-
axis is the abrasion index (0-4; see Table 3); Y-axis is the number of specimens. Specimen counts in A: 0
415 1 652 2 178 3 81 4 44. Specimen counts in B: 0 71 1 41 2 14 3 7 4 5.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
62
01234
2
6
10
14
18
B
01234
5
15
25
35
45
55
A
Figure 46. Abrasion of Kem Kem fossils (FSAC-KK collection). A Iferda N’Ahouar B Valley near
Boumerade. X-axis is the abrasion index (0-4; see Table 3); Y-axis is the number of specimens. Specimen
counts in A: 0 37, 1 58, 2 40, 3 13, 4 4. Specimen counts in B: 0 17, 1 15, 2 11, 3 4, 4 3.
1
234567891011
50
150
250
350
450
B
1234567891011121314151617181920212223242526
200
600
1000
1400
A
Figure 47. Size of vertebrate fossil elements found in the Kem Kem Group (FSAC-KK collection). A All
localities. B Gara Sbaa. X-axis indicates size in 20 mm size bins; Y-axis indicates numbers of specimens.
Specimen size bins: 1 0-20 mm 2 21-40 mm 3 41-60 etc.
Kem Kem Group of Morocco 63
12345678910 11 12 13 14 15 16 17 18 19 20 21
5
15
25
35
45
B
123456789
50
150
350
450
550
650
A
250
Figure 48. Size of vertebrate fossil elements found in the Kem Kem Group (FSAC-KK collection). A
Boumerade. B Aferdou N’Chaft. X-axis indicates size in 20 mm size bins; Y-axis indicates numbers of
specimens. Specimen size bins: 1 0-20 mm 2 21-40 mm 3 41-60 etc.
1
23456789
5
10
15
20
25
30
B
1
23456789101112131415
A
15
30
45
60
Figure 49. Size of vertebrate fossil elements found in the Kem Kem Group. A Iferda N’Ahouar B 'Valley
near Boumerade' locality. X-axis indicates size in 20 mm size bins; Y-axis indicates numbers of specimens.
Specimen size bins: 1 0-20 mm 2 21-40 mm 3 41-60 etc.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
64
specimens are not preserved in situ, some outcrops with considerable section exposed
create uncertainty as regarding the formational provenance of specimens.
Very large fossil specimens are rare. Two partial sauropod limb bones were found
in place. In 1995 the proximal end of a large sauropod ulna was discovered in the Gara
Sbaa Formation, measuring 54 cm across its proximal articular end (see taxonomic sec-
tion for further details). In 2008 the mid-section of a large titanosaur humerus was also
recovered in this formation, measuring approximately 25 cm at the narrowest portion of
its shaft and with a reconstructed length of approximately 1.5 m (Ibrahim et al. 2016).
In sum, there appears to be a strong taphonomic bias against very small (< 2 cm),
large (> 6 cm), and soft (plant, nonvertebrate) specimens in the majority of localities
in both the Gara Sbaa and Douira formations. e largest sample is from the locality
Gara Sbaa, where nearly all vertebrate specimens fall into the 2–6 cm size range.
Systematics
Plant and nonvertebrate fossils
At the pond locality Oum Tkout, thin lms are suggestive of bacteria or fungi (Eumy-
cetes) (Fig. 50). Common plant fossils on Kem Kem outcrop include weathered pieces
of petried wood that probably represent araucarian conifers. Other macroplant re-
mains at the pond locality Oum Tkout include other gymnosperms and spermatopsids
(Fig. 51) and angiosperms (Garassino et al. 2006).
Body fossils of nonvertebrates are preserved almost exclusively at the pond locality
Oum Tkout. e ne-grained mud sediment of the pond oor preserves whole and
partial specimens of soft-bodied mollusks, crustaceans (prawn, macruran decapod, Fig.
52), and larval and mature insects (Fig. 53). e prawn Cretapenaeus berberus has been
described from the freshwater locality Oum Tkout in the Douira Formation (Garassi-
no et al. 2006) as well as in the overlying Akrabou Formation (Garassino et al. 2008).
At least one macruran decapod remains to be described from Oum Tkout.
Elasmobranchii Bonaparte, 1838
e hooked rostral teeth of the sclerorhynchid, Onchopristis numidus, are the most
common vertebrate fossil in Kem Kem group sediments (Dutheil 1999b, Cavin et al.
2010), readily found on outcrops along the length of the Guir and Kem Kem Hama-
das (Fig. 54). is common northern African sclerorhynchid, initially described under
the genus Gigantichthys from Algeria (Haug, 1905) and later placed in a new genus
Onchopristis (Stromer 1917), has been recorded in Cenomanian-age rocks elsewhere in
Algeria (Broin et al. 1971) and at sites across northern Africa, including Niger (Lap-
parent 1953, Dutheil 2001), Libya (Lefranc 1958) and Egypt (Stromer 1917, Tabaste
Kem Kem Group of Morocco 65
Figure 50. Possible biolm (bacteria, fungi) from Oum Tkout, Douira Formation. Scale bar equals 5 mm.
Figure 51. Simple and compound leaves are among the plant remains from Oum Tkout, Douira Forma-
tion. Scale bars equal 1 cm in A and B, 5 mm in C and 5 cm in D.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
66
Figure 52. Decapod prawn Cretapenaeus berberus (Garassino et al. 2006) from Oum Tkout, Douira
Formation. Scale bar equals 5 mm.
Figure 53. Dragony larva (Odonata indet.) from Oum Tkout, Douira Formation. Scale bar equals 5 mm.
Kem Kem Group of Morocco 67
Figure 54. Selected isolated remains of the sclerorhynchid Onchopristis numidus. Rostral fragment with
the bases of two rostral teeth in place (NMC 41876) in (A) ?dorsal, (B) ?ventral and (C) lateral view.
Section of a large rostrum (FSAC-KK 937) in (D) dorsal, (E) ventral, (F) anterior and (G) posterior views
H Small section of rostrum (NMC 50397) I Isolated rostral tooth J Placoid scale (MNHN-MRS 72) D
and H reconstructed to show the approximate shape of the rostral blade. Scale bars equal 5 cm in A-H,
2 cm in I and J.
1963, Werner 1989). Most of the other elasmobranch genera reported in the Kem
Kem Group come from screen-washing sediment for micro-vertebrate sampling (Du-
theil 1996, Sereno et al. 1996, Cavin et al. 2010). ese genera pertain to two clades
of elasmobranchs, Hybodontoidea and Neoselachii (Table 8).
†Hybodontoidea Owen, 1846. e Kem Kem hybodontoids, represented by
isolated teeth and n spines, appear to be attributable to three genera, Bahariyodon
bartheli, Distobatus nutiae, and Tribodus sp. (Dutheil 2001), and two indeterminate
acrodontids (Sereno et al. 1996, Dutheil 1999a, Dutheil et al. 2001, Table 8). e
genus Hybodus has yet to be reliably reported among isolated teeth in Kem Kem sedi-
ments. Diagnostic features of the genus and species reside in its acuminate, multicus-
pid teeth and cranial features (Maisey 1987); its n spines thus far have not proven to
be diagnostic.
Isolated tooth and n spine specimens, in addition, cannot be paired with con-
dence. Two n spine morphotypes occur in Kem Kem sediments, one with longitudi-
nal striations and the other with tubercles (Fig. 55A–D). Longitudinal striations are
known on the n spines in Lissodus and Tribodus as well as in Hybodus, whereas n
spines with tubercules are reported in Asteracanthus. e partial n spines collected at
Aferdou N’Chaft, Boumerade, and Gara Sbaa may pertain to Tribodus or Acrodonti-
dae indet., but this remains to be substantiated on the basis of association.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
68
Table 8. e vertebrate assemblage recorded to date in the Kem Kem Group.
Elasmobranchii Bonaparte, 1838
†Hybodontoidea Owen, 1846
Asteracanthus aegyptiacus Stromer, 1927
Bahariyodon (Lissodus) bartheli (Werner, 1989)
Distobatus nutiae Werner, 1989
Tribodus Brito & Ferreira, 1989, sp. indet.
†Acrodontidae Casier, 1959, gen. et sp. indet.
Neoselachii Compagno, 1977
Galea Shirai, 1996
Haimirichia amonensis (Cappetta & Case, 1975)
†Cretoxyrhinidae Glickman, 1958, gen. et sp. indet.
Cenocarcharias tenuiplicatus Cappetta & Case, 1975
Batoidea Compagno, 1973
Onchopristis numidus (Haug, 1905)
Marckgraa lybica Weiler, 1935
Actinopterygii Klein, 1885
Diplospondichthys moreaui Filleul & Dutheil, 2008
Cladistia Cope, 1871
Bartschichthys Gayet & Meunier, 1996, sp. indet.
Sudania Werner & Gayet, 1997, sp. indet.
Serenoichthys kemkemensis Dutheil, 1999b
Bawitius Grandsta, et al. 2012, sp. indet.
Ginglymodi Cope, 1872
†Lepisosteiformes Hay, 1929
Adrianaichthys pankowskii (Forey et al., 2011)
Lepisosteidae Cuvier, 1825, gen. et sp. indet.
Oniichthys falipoui Cavin & Brito, 2001
Obaichthys africanus Grande, 2010
Dentilepisosteus kemkemensis Grande, 2010
Holostei Müller, 1844 (emended by Grande, 2010)
Amiiformes Hay, 1929
Calamopleurus africanus Forey & Grande, 1998
Teleostei Müller, 1846
†Tselfatiiformes Nelson, 1994
Concavotectum moroccensis Cavin & Forey, 2008
Ichthyodectiformes Bardack & Sprinkle, 1969
Aidachar (Cladocyclus) pankowskii Forey & Cavin, 2007
Osteoglossomorpha Greenwood et al., 1966
Palaeonotopterus greenwoodi Forey 1997
†Notopteridae Bleeker, 1959, gen. et sp. indet.
Acanthomorpha Rosen, 1973
Spinocaudichthys oumtkoutensis Filleul & Dutheil, 2001
Clupeomorpha Greenwood et al., 1966
Diplomystus Cope, 1877, sp. indet.
Triplomystus Forey, Yi, Patterson, & Davis, 2003, sp. indet.
Characiformes Regan, 1911, gen. et sp. indet.
Sarcopterygii Romer, 1955
Actinistia Cope, 1871
†Mawsoniidae Schultze, 1993
Axelrodichthys lavocati Tabaste, 1963
Dipnoi Müller, 1846
Ceratodontidae Gill, 1872
Ceratodus humei Priem, 1914
Neoceratodus africanus (Haug, 1905)
Kem Kem Group of Morocco 69
Arganodus tiguidensis (Tabaste, 1963)
Amphibia Gray, 1825
Caudata Scopoli, 1777
Sirenidae Gray, 1825
Kababisha Evans et al., 1996, sp. indet.
Anura Fischer von Waldheim, 1813, gen. et sp. indet.
Pipidae Gray, 1825
Oumtkoutia anae Rage & Dutheil, 2008
Testudines Batsch, 1788
Pleurodira Cope, 1865
†Araripemydidae Price, 1973, gen. et sp. indet.
†Euraxemydidae Ganey et al., 2006
Dirqadim schaeeri Ganey et al., 2006
†Podocnemidoidea Cope, 1868
Hamadachelys escuilliei Tong & Buetaut, 1996
Galianemys whitei Ganey et al., 2002
Galianemys emringeri Ganey et al., 2002
Squamata Oppel, 1811
Ophidia Brongniart, 1800
Norisophis begaa Klein et al., 2017
†Lapparentophiidae Hostetter, 1959
Lapparentophis ragei Vullo, 2019
†Simoliophiidae Nopcsa, 1925
Simoliophis cf. libycus Nessov et al., 1998
†Nigerophiidae Rage, 1975, gen. et sp. indet.
†Madtsoiidae Hostetter, 1961, gen. et sp. indet.
Iguania Cope, 1864
Jeddaherdan aleadonta Apesteguía et al., 2016
†Borioteiioidea Nydam et al., 2007
Bicuspidon hogreli Vullo & Rage, 2018
Crocodyliformes Hay, 1930
†Peirosauridae Gasparini, 1982
Hamadasuchus rebouli Buetaut, 1994
†Notosuchia Gasparini, 1971
Araripesuchus rattoides Sereno & Larsson, 2009
†Candidodontidae Carvalho et al., 2004
Lavocatchampsa sigogneaurussellae Martin and de Lapparent de Broin, 2016
†Sphagesauridae Kuhn, 1968, gen. et sp. indet.
Neosuchia
†Stomatosuchidae Stromer, 1925
Laganosuchus maghrebensis Sereno & Larsson, 2009
†Aegyptosuchidae Kuhn,1936
Aegisuchus witmeri Holliday & Gardner, 2012
†Pholidosauridae Zittel & Eastman, 1902
Elosuchus cheriensis de Lapparent de Broin, 2002
†Pterosauria Kaup, 1834
†Ornithocheiridae Seeley, 1870
Siroccopteryx moroccensis Mader & Kellner, 1999
Coloborhynchus uviferox Jacobs et al., 2019
Ornithocheirus Seeley, 1869, sp. indet.
Anhanguera Campos & Kellner, 1985, sp. indet.
†Azhdarchidae Nessov, 1984
Alanqa saharica Ibrahim et al., 2010
Xericeps curvirostris Martill et al., 2018
†Tapejaridae Kellner, 1989, gen. et sp. indet.
Afrotapejara zouhrii Martill et al., 2020
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
70
?†Chaoyangopteridae
Apatorhamphus gyrostega McPhee et a., 2020
Dinosauria Owen, 1842
†Ornithischia Seeley, 1888, gen. et sp. indet.
†Sauropoda Marsh, 1878
†Rebbachisauridae Bonaparte, 1997
Rebbachisaurus garasbae Lavocat, 1954b
†Titanosauria Bonaparte & Coria, 1993, gen. et sp. indet.
eropoda Marsh, 1881, gen. et sp. indet.
†Noasauridae Bonaparte & Powell, 1980, gen. et sp. indet.
†Abelisauridae Bonaparte & Novas, 1985, gen. et sp. indet.
Deltadromeus agilis Sereno et al., 1996
†Carcharodontosauridae Stromer, 1931
Carcharodontosaurus saharicus Stromer, 1931
†Spinosauridae Stromer, 1915
Spinosaurus aegyptiacus Stomer, 1915
†Dromaeosauridae Colbert & Russell, 1969, gen. et sp. indet.
Rare teeth of Bahariyodon bartheli (Werner 1989, Dun 2001) have been recov-
ered from Douira and Dar el Karib localities in the Douira Formation. Teeth of Disto-
batus nutiae, previously known only from the Bahariya Formation (Werner 1989) and
from the Cenomanian of the Draa Ubari in Libya (Nessov et al. 1998, Rage and Cap-
petta 2002), were also collected from these two localities. A rare tooth morphotype,
here attributed to Tribodus sp. (Table 8), is rectangular with vertical ridges, resembling
the Brazilian species Tribodus lima (Brito and Ferreira 1989) and Egyptian species Tri-
bodus kuehnei from the Bahariya Formation (Werner 1989).
Neoselachii Compagno, 1977
Galea, Wagler, 1851. e pond locality Oum Tkout has yielded isolated teeth of lam-
niform elasmobranchs (Dutheil 1999a). e remaining diverse ichthyofauna from this
locality is freshwater (Dutheil 1999a). One tooth (Fig. 55E, F) pertains to the mack-
erel shark Haimirichia amonensis and another one to the cretoxyrhinid Cenocarcharias
tenuiplicatus (Cappetta and Case 1975).
Batoidea Compagno, 1973. Rostral teeth of the large-bodied, sclerorhynchid ba-
toid, Onchopristis numidus (Haug 1905), are the most abundant vertebrate element in
Kem Kem sediments (Martill and Ibrahim 2012). e teeth of the rostrum and centra
are occasionally found in place in both formations (Fig. 54A-C). New cranial and axial
material of this taxon include a large rostrum (Fig. 54D-G), an articulated series of
more than 50 vertebrae (Fig. 56), and an exceptional new specimen under study that
preserves portions of the rostrum and skull in association with vertebral centra (Du-
theil and Brito 2009).
e rostrum was recovered in two pieces from the Valley near Boumerade local-
ity (Fig. 9, locality 7) near a partial quadrate that may pertain to Spinosaurus (Fig.
38A). With both pieces of the tapering rostrum positioned as they would be in life, it
measures more than 40 cm in length (Fig. 54D, E). Anteriorly it tapers in width, and
Kem Kem Group of Morocco 71
ventrally it is marked by a sharp-edged trough approximately 5 mm deep and inset
from the lateral margin (Fig. 54). A linear, straw-like texture is present on both dorsal
and ventral surfaces of the calcied rostrum.
e calcied disc-shaped, biconvex vertebrae have concave sides and decrease in
diameter toward the distal end of the series (Fig. 56), which places the series in the
posterior portion of the axial column. e articulated series measures more than 80 cm
and pertains to an individual that was probably several meters in length.
Another specimen of Onchopristis numidus, which was collected commercially
from Kem Kem sediments, preserves portions of the cranium and several anterior ver-
tebrae (Dutheil and Brito 2009). It provides direct evidence of association between
the rostrum and rostal teeth of O. numidus and its oral teeth, oral osteoderms and
vertebral centra. is specimen conrms previous suggestions by Tabaste (1963) that
the common discoid centra in Kem Kem sediments initially described as Platyspondylus
foureaui (Haug, 1905), pertain to this species.
Two additional Kem Kem batoids have been found in screen-washed sediment at
Douira in the Douira Formation (Dutheil 2001, Table 8). Marckgraa lybica, initially
Figure 55. Elasmobranch fossils from Morocco and Egypt. Hybodontoidea n spine with tubercles
(FSAC-KK 943), in (A) lateral and (B) posterior view. Hybodontoidea n spine (FSAC-KK 944), orna-
mented with striations in (C) lateral and (D) posterior view. Lamniform tooth (Poi-SGM 52) referred
to Haimirichia amonensis in (E) labial and (F) lingual view. Lamniform tooth (Poi-SGM 53) referred to
Cenocarcharias cf. tenuiplicatus in (G) labial and (H) lingual views. I Rostral tooth of Peyeria libyca (Poi
SGM 61). Scale bars equal 3 cm in A-D, 3 mm in E and F, 2 mm in G and H, 1 cm in I.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
72
Figure 56. Associated elasmobranch vertebrae likely referable to Onchopristis numidus from the Kem
Kem Group. A Reconstructed vertebral series. B-D Select vertebrae with sedimentary matrix. Scale bars
equal 10 cm in A, 5 cm in B-D.
Kem Kem Group of Morocco 73
described from the Bahariya Formation of Egypt (Weiler 1935, Table 8) is represented
by 13 teeth. e pristid Peyeria libyca was initially described from the Bahariya Forma-
tion of Egypt (Weiler 1935) and is represented by three teeth, although new evidence
suggests it may comprise non-rostral denticles of Onchopristis numidus (Sternes and
Shimada 2019). Two sections of caudal centra recovered from the pond locality of
Oum Tkout may pertain to batoids on the basis of their numerical dominance among
Kem Kem elasmobranchs.
Actinopterygii Klein, 1885
Actinopterygii are usually recovered as isolated bones except in rare instances and at
the pond locality Oum Tkout, which has yielded nearly complete skeletons. Actinop-
terygii include basal clades, such as polypterids (Cladistia), lepisosteids and seminoti-
formes (Ginglymodi), Amiiformes, and a range of teleosts (Table 8). e review below
adds new information to previous summaries of the Kem Kem ichthyofauna (Dutheil
1999a, Cavin et al. 2015).
Cladistia Cope, 1871. Cladistians are widespread in Africa (Stromer 1936, Stew-
art 1994, Gayet and Werner 1997) and have also been reported from the Americas
(Gayet and Meunier 1991). Isolated ganoid scales are present in both formations of
the Kem Kem Group, suggesting that polypterids may have been a common element
of the ichthyofauna.
Four genera have been recorded. At the pond locality Oum Tkout in the Douira
Formation, several articulated skeletons have been recovered of the small cladistian
Serenoichthys kemkemensis (Dutheil 1999b, Fig. 57). At the same locality, isolated pin-
nulae (the spine that supports each dorsal nlet) are referable to Bartschichthys sp.
(Dutheil 1999a), based on similarities to Bartschichthys arnouldi from similar age rocks
in Niger (Gayet and Meunier 1996). Dutheil (1999a) referred another isolated pin-
nula from the same horizon to Sudania sp., as it closely resembled specimens from the
Cenomanian Wadi Milk Formation in Sudan (Werner and Gayet 1997).
Large jaw bones with teeth (Cavin et al. 2015) and scales (Meunier et al. 2016)
from the Kem Kem Group were recently referred to the Egyptian cladistian Bawitius.
An isolated premaxilla (Fig. 58) also may pertain to this large-bodied genus. e bone
has a pitted surface texture. e teeth are large, hollow and ankylosed to the bone.
ese features closely resemble a better-preserved partial skull from beds of Cenoma-
nian age in Niger (Fig. 59). e Niger specimen is associated with scales, allowing
positive referral to Cladistia.
Ginglymodi Cope, 1872, Semionotiformes Arambourg & Bertini, 1958.
Several authors describe a range of ginglymoid and semionotiform shes from dis-
articulated material (Dutheil 1999a, Cavin and Brito 2001, Grande 2010, Cavin et
al. 2015). e moderate-sized Oniichthys falipoui and Obaichthys africanus are known
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
74
Figure 57. Serenoichthys kemkemensis Dutheil, 1999 from the Douira Formation. Scale bar equals 1 cm.
Figure 58. Large polypterid premaxilla (FSAC-KK 209) from the Kem Kem Group. In (A) anterior, (B)
posterior, (C) lateral, (D) dorsal and (E) ventral view. Scale bar equals 3 cm. Abbreviations: f foramen t tooth.
from partial skeletons, and Dentilepisosteus kemkemensis is represented by scales (Cavin
et al. 2015). Other isolated scales that likely pertain to this group measure more than
50 mm in length and are indicative of large-bodied species (Fig. 60). Pycnodonts have
also been identied among disarticulated remains from the Kem Kem Group.
Kem Kem Group of Morocco 75
Figure 59. Large polypterid (MNBH IGU23) from the Cenomanian of Niger. Associated right and left
premaxillae in (A) anterior, (B) ventral and (C) lingual view. Scale bar equals 3 cm.
Amiiformes Hay, 1929. Isolated teeth and several dentary fragments (Fig. 61A–
D) pertain to amiids, which have been found in both formations of the Kem Kem
Group. A partial amiiform skull, described as Calamopleurus africanus (Forey and
Grande 1998), diers in skull proportions but otherwise is similar to the Brazilian spe-
cies C. cylindricus (Cavin et al. 2015).
A curved dentary from Aferdou N’Chaft has at least 20 alveoli for small triangular
teeth and lacks interdental plates (Fig. 62E–I). e texture and form of the dentary
resembles that in amiids (Martinelli et al. 2013).
Teleostei Müller, 1846. More than a dozen genera of teleost shes have been
described from the Kem Kem Group (Table 8). Several are known from partial or
complete skeletons from Oum Tkout. e elongate Diplospondichthys moreaui (Fig.
63) has an unusual combination of features that has left its position uncertain within
Teleostei (Filleul and Dutheil 2004). e elongate freshwater acanthomorph Spinocau-
dichthys oumtkoutensis (Fig. 64) has also been recorded at the same locality (Filleul and
Dutheil 2004).
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
76
Figure 60. Scales of a large holostean from the Kem Kem Group. A FSAC-KK 530 (Gara Sbaa) B NMC
50434-A C FSAC-KK 531 (Gara Sbaa) D NMC 50434-C E NMC 50434-B F Lateral view of NMC
50817 G Medial view of NMC 50817 H Lateral view of NMC 41932 I Medial view of NMC 41932 (one
of the largest known teleost scales from the Kem Kem Group). Scale bar equals 3 cm.
Forey and Cavin (2007) described a well-preserved ichthyodectiform braincase from
an unknown locality in eastern Morocco as Cladocyclus pankowskii, which later was
placed in the genus Aidachar (Cavin et al. 2015). A well-preserved dentary (Fig. 62A-C)
is referable to A. pankowskii and is also similar to the ichthyodectine Xiphactinus (Leidy
1870, Schwimmer et al. 1997, Fig. 62D). Osteoglossiform and notopterid remains in-
cluding skull fragments were assigned to Palaeonopterus greenwoodi (Forey 1997, Tav-
erne 2000, Cavin and Forey 2001a). e median lingual dental plate of this species is
composed of several superimposed layers of adjacent teeth (Meunier et al. 2013), which
were previously described in error as Pletodus sp. (Dutheil 1999a). Erfoudichthys rosae is
a small-bodied teleost of unknown anity, known from an isolated skull (Cavin et al.
2015). Previously it was thought to be a gonorynchiform (Pittet et al. 2010).
Sarcopterygii Romer, 1955
Actinistia Cope, 1871. Isolated cranial bones pertaining to large-bodied coelacanths
are present in both formations of the Kem Kem Group (Figs 65, 66). Numerous iso-
lated cranial bones and scales were collected at Boumerade and Gara Sbaa in the Gara
Kem Kem Group of Morocco 77
Sbaa Formation. Although the size and ornamentation of dermal cranial bones are eas-
ily recognized, their generic and specic assignment remains uncertain.
e genera Mawsonia and Axelrodichthys were originally described from South Amer-
ica on the basis of complete specimens in nodules of late Early Cretaceous age (Maisey
1986). In contrast, the African material largely consists of isolated bones from Morocco
and Algeria (Tabaste 1963, Wenz 1981, Cavin and Forey 2004). Cavin et al. (2015) sug-
gested that, in addition to Mawsonia lavocati, a second large coelacanth may be present
within the Kem Kem Group, assigning an isolated cranial bone to the South American
genus Axelrodichthys. More recently, after a review of actinistians assigned to the gen-
era Mawsonia (Woodward 1907) and Axelrodichthys (Maisey 1986) Mawsonia lavocati
Figure 61. Actinopterygian remains from the Kem Kem Group. A-C Possible amiid dentary frag-
ment (MDM 02) in right lateral, medial and dorsal (occlusal) views D Possible amiid dentary fragment
(MSNM V 6417) E Dentary of an unidentied teleost (NMC 41883) F Possible notopterid dental plate
(NMC 50863) G Probable teleost bone (NMC 41900) H Possible teleost parasphenoid (NMC 50864)
I, J Possible Obaichthys africanus (Cavion et al. 2015) scales (NMC 50437) K, L Possible seminotiform
scale (NMC 50867A) M-P Possible lepisosteid or obaichthyid vertebra in anterior, posterior, dorsal and
ventral view. Scale bars equal 1 cm in A-D, 2 cm in E-L, 2 cm in M-P.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
78
Figure 62. Isolated teleost dentaries from the Kem Kem Group. A-C Partial dentary of an ichthyodec-
tiform with anities to Xiphactinus and Cladocyclus (NMC 41882) in right lateral, medial and dorsal
views D Right dentary of Xiphactinus audax (FHSM VP-2973) from the Late Cretaceous of the USA in
medial view (courtesy of Mike Everhart) E-I Isolated dentary (FSAC-KK 906) of possible amiid in right
lateral, medial, dorsal (occlusal) ventral, and medial (close-up) views J-K Dentary (NMC 41884) in ?right
lateral and dorsal (occlusal) view. L-M Dentary of an unidentied predatory teleost with rostral tooth of
Onchopristis numidus (NMC 50836) in lateral and medial view. Scale bars equal 5 cm in A-C, E-H, 10
cm in D, 3 cm in I-K, 5 cm in L and M. Abbreviation: rt rostral tooth.
was included in Axelrodichthys as Axelrodichthys lavocati by Carnier Fragoso et al. (2019).
Yabumoto and Uyeno (2005) described a partial skull with lower jaws from an uncertain
locality within the Kem Kem Group. ey also provide a revision of the species that
serves as a guide for assignment of isolated material.
Kem Kem Group of Morocco 79
Figure 63. Diplospondichthys moreaui Filleul and Dutheil, 2004 from the Kem Kem Group. Scale bar
equals 2 cm.
Figure 64. Spinocaudichthys oumtkoutensis Filleul and Dutheil, 2002 from the Kem Kem Group. Scale
bar equals 5 mm.
Measuring approximately 30 cm long, the skull conrms the large size of the genus
Axelrodichthys in lake and river deposits on Africa and South America (Carvalho and
Maisey 2008, Carnier Fragoso et al. 2019). Axelrodichthys lavocati may have grown to
a body length in excess of 4 m.
Dipnoi Müller, 1844. Lungsh tooth plates are common in both formations of
the Kem Kem Group (Fig. 67). ey vary considerably in size and ornamentation with
distinctive morphological dierences.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
80
Figure 65. Isolated elements referable to Axelrodichthys lavocati or a closely related form from the Kem
Kem Group. A Isolated pterotic (NMC 41877) B Right angular (NMC 50816). Parasphenoid (NMC
41813) in (C) dorsal, (D) anterior and (E) posterior view. Visceral arch element (NMC 50828) in (F)
lateral and (G) medial view. Visceral arch element (NMC 50827) in (H) lateral and (I) medial view. Iso-
lated postparietal of (FSAC-KK 157), collected at locality 5 (Figure 9) in (J) dorsal and (K) ventral views.
LIsolated operculum (MNHN-MRS 926). M Left angular (MNHN-MRS 78), part of type material of
A. lavocati (Tabaste 1963). Scale bars equal 5 cm in A–I, 5 cm in J and K, 10 cm in L and M. Abbrevia-
tions: ant ap anterior apophysis desc pr descending process of postparietal.
Kem Kem Group of Morocco 81
Figure 66. Large specimens from the Kem Kem Group likely referable to Axelrodichthys. Possible frag-
ment of palatoquadrate region preserving a large part of the pterygoid (MNHN-MRS 926) in (A) lateral
and (B) medial view. Large quadrate with a small section of the pterygoid (MPDM 14) in (C) lateral and
(D) medial view. E Partial palate of Axelrodichthys (MNHN-MRS 1761) in lateral view. Quadrate (NMC
41994) in (F) lateral, (G) medial and (H) ventral view. Scale bars equal 10 cm in A, B and E, and 3 cm
in C, D and F-H. Abbreviations: pt pterygoid q quadrate.
Ceratodontidae Gill, 1872. e generic taxonomy of fossil lungsh, which is
based almost exclusively on toothplates, has been unsettled and species have been
variously assigned to the extinct genus Ceratodus or to the living Australian ge-
nus Protopterus and living African genus Neoceratodus. e most recent assessment
(Cavin et al. 2015) attributes Kem Kem lungsh to three ceratodontid genera, Cera-
todus, Neoceratodus, and Arganodus (Table 8). Toothplates with deeply incised ridges
(Fig. 67A) are the most common and were initially identied as Ceratodus africanus
(Haug 1905, Tabaste 1963, Martin 1984). More recently, these are referred to Ne-
oceratodus africanus (Martin 1982, Werner 1995, Cavin et al. 2015), which has been
reported across all of northern Africa in similar age beds (Haug 1905, Peyer 1925,
Werner 1995, Tabaste 1963, Schlüter and Schwarzhans 1978, Schaal 1984, Cavin
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
82
Figure 67. Size variation in lungsh tooth plates from the Kem Kem Group. A UCRC PV62, likely Ne-
oceratodus africanus B FSAC-KK 2735. Note that some size dierences can be even greater in exceptional
specimens. Scale bar equals 3 cm.
et al. 2010). In the Kem Kem Group, the toothplates of N. africanus can measure
more than10 cm.
Tabaste (1963) described small toothplates with low ornamentation and only four
low ridges as Ceratodus humei. ese have also been found across northern Africa in
similar age beds (Haug 1905, Werner 1993, Martin 1984). Martin (1984) placed this
species in the extant genus Protopterus, but later it was returned to the genus Ceratodus
(Churcher and De Iuliis 2001). Recently Cavin et al. (2015) referred small toothplates
with a characteristic radiating pattern of ridges to Arganodus tiguidensis, a species de-
scribed originally from Algeria (Tabaste 1963) and later reported in Niger (Broin et al.
1974) and Brazil (Candeiro et al. 2011).
Amphibia Gray, 1825
Caudata Scopoli, 1777
Sirenidae Gray, 1825. Several localities in the ner-grained Douira Formation have
yielded two braincases and 38 vertebrae pertaining to salamanders (Rage and Dutheil
2008). Most of the vertebrae come from the pond locality Oum Tkout, whereas the
braincases were found at Taouz and Talidat localities. e occipital condyle of each
partial braincase is transversely broad (Fig. 68A, B), which resembles the condition
in the Sudanese genus Kababisha (Evans et al. 1996). e isolated vertebrae, which
are tentatively referred to the same genus, resemble those of Kababisha and the South
American genus Noterpeton (Rage and Dutheil 2008). e keeled centra, which are
2–3 mm in length, are anked to each side by ange-shaped transverse processes. A
foramen opens onto the dorsal surface of the ange. Unlike the Sudanese site, only a
single sirenian appears to be present in the Douira Formation.
One trunk or anteriormost caudal vertebra of an indeterminate salamander is
known from the Algerian locality Oued Bou Seroual in a level comparable to the
Kem Kem Group of Morocco 83
Figure 68. Amphibia and Squamata from the Douira Formation. Cf. Kababisha sp. braincase (UCRC
PV50) from Oum Tkout in (A) lateral and (B) posterior view. Oumtkoutia anae braincase (UCRC PV63)
from Oum Tkout in (C) lateral and (D) ventral view. Simoliophis cf. S. lybicus trunk vertebra UCRC
PV127) from Douira in (E) anterior and (F) lateral view. Figures modied from Rage and Dutheil (2008).
Scale bars equal 1 mm in A and B, 2 mm in C and D, 3 mm in E and F.
Douira Formation and approximately 25 km distant from Oum Tkout. e mor-
phology of this procoelous vertebra suggests that it pertains to an elongate, snake-like
salamander (Alloul et al. 2018).
Anura Fischer von Waldheim, 1813. A partial braincase, jaw fragments, and pro-
coelous vertebrae probably pertain to several species of non-pipid anurans, but the
remains are too fragmentary to assign to particular families (Rage and Dutheil 2008).
Pipidae Gray, 1825. e majority of the anuran material collected in the Douira
Formation, as in other Gondwanan localities, is referable to the Pipidae (Rage and Du-
theil 2008). e holotype for a new genus and species, Oumtkoutia anae, was found at
the pond locality Oumt Tkout (Fig. 68C, D). e subtriangular cranium that narrows
anteriorly and the distinctive vertebral morphology distinguish this species from other
pipids (Rage and Dutheil 2008). Other localities (Dar el Karib, Taouz) generated ad-
ditional isolated bones. In all there are 22 partial braincases, ve vertebrae, and seven
pelvic fragments.
Testudines Batsch, 1788
Testudines are common among vertebrate fossils in the Kem Kem Group (Gmira
1995). Isolated shell fragments are the most common (Fig. 69) followed by shell pieces
(Fig. 70), vertebrae and limb bones (Fig. 71) and, rarely, partial plastron and carapace
(Fig. 72) or skull material (Fig. 73). Named Kem Kem Group testudines, thus far, are
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
84
Figure 69. Testudinid shell fragments from the Kem Kem Group. Partial plastron with sutures (UCRC
PV165) in (A) dorsal and (B) ventral view. Large shell fragment (UCRC PV166) with sutures highlighted
by red and dark lines (C). Rounded and smooth shell fragment (MNHN-MRS 290) (D). MNHN-MRS
382 (E). Dark-colored carapace elements from Kouah Trick locality (MNHN-MRS 1813-1815) in (F,
H, J) dorsal and (G, I, K) ventral view. Scale bar equals 5 cm.
based solely on isolated crania (Fig. 73). ese were collected commercially from un-
certain localities and horizons (Tong and Buetaut 1996, Ganey et al. 2002, 2006).
Cranial material pertains, thus far, exclusively to pleurodires; cryptodires have
yet to be reported. ree genera of euraxymydid and podocnemidoid pleurodires
were described on the basis of isolated crania (Ganey et al. 2002, 2006); postcranial
remains have yet to be denitively associated with any of the three genera Dirqadim,
Hamadachelys, and Galianemys. Araripemydid pleurodires are known only from iso-
Kem Kem Group of Morocco 85
Figure 70. Possible araripemydid and podocnemidinuran shell fragments from the Kem Kem Group.
Possible araripemydid plastral element (MNHN-MRS 172) in (A) dorsal and (B) ventral view. MNHN-
MRS 1175 in (C) dorsal and (D) ventral view. NMC 41928 in (E) dorsal and (F) ventral view. Partial
podocnemidinuran (?Galianemys) plastron collected at Iferda N’Ahouar (UCRC PV167) in (G) dorsal
and (H) ventral view. Cross-sectional view of a typical shell fragment showing dense and cancellous bone
(I). Scale bars equal 3 cm in A-F, 3 cm in G and H, 1 cm in I.
lated carapace fragments with pitted texture (Fig. 70A-F); no cranial material has
been discovered.
Pleurodira Cope, 1865
Araripemydidae Price, 1973. e attened, fragile-shelled araripemydids are much
better known from slightly older (Aptian-Albian) rocks to the south in Niger (Sereno
and ElShae 2013) and contemporary deposits in Brazil, which were located across
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
86
Figure 71. Isolated turtle postcrania from the Kem Kem Group. Pelomedusoides indet., cervical vertebra
(BSPG 2006 I 61) in (A) dorsal, (B) left lateral, (C) anterior and (D) posterior view. ?Testudines indet.,
proximal part of femur (NMC 41973) in (E) anterior and (F) posterior view. Testudines indet., metapo-
dial (NMC 41975) in (G) anterior, (H) proximal and (I) distal view. Testudines indet., selected metapodi-
als (NMC 50846 A-E) in (J) dorsal view. Scale bars equal 3 cm in A-D, 3 cm in E and F, 3 cm in G-J.
Figure 72. Partial shell and girdle bones of cf. Galianemys sp. (UCRC PV18) in (A) dorsal and (B)
anterodorsolateral view. Scale bar for A: 10 cm.
Kem Kem Group of Morocco 87
Figure 73. Turtle skull elements from the Kem Kem Group. One of two undescribed skulls likely refer-
able to Galianemys whitei (MNHN-MRS 2098) in (A) dorsal, (B) ventral, (C) anterior and (D) right
lateral view. Partial skull of Galianemys sp. (FSAC-KK 938) in (E) dorsal, (F) ventral and (G) anterior
view. Skull of Dirqadim schaeeri (MDEt 41) in (H) dorsal, (I) ventral and (J) right lateral view. Scale bars
equal 3 cm in A-D, E-G and H-J. Abbreviations: bo basioccipital, f frontal, m maxilla, op opisthotic, p
parietal, pf prefrontal, pl palatine, pt pterygoid, q quadrate, so supraoccipital.
a then narrower Atlantic Ocean (Ganey et al. 2006). e araripemydid carapace is
composed of thin, at, densely pitted bones that resemble carapace fragments from
the Kem Kem Group (Fig. 70A-F). We tentatively refer this Kem Kem material to the
Araripemydidae on the basis of these features and await the recovery of more complete
specimens (Table 8).
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
88
at decision, to limit referral of partial isolated shell elements of this form to
Araripemydidae, is prudent and based on a cladistic diagnosis of the family that speci-
cally cites shell structure and texture among some 20 synapomorphies that unite the
two valid genera Araripemys and Laganemys (Sereno and ElShae 2013: 219). Some
authors, in contrast, have attempted to refer isolated shell pieces from South America
and Africa to specic araripemydid genera or species, when the material does not ex-
hibit more specic diagnostic features.
in ornamented shell material characterizing araripemydids is rare in the Kem
Kem Group (Fig. 70A-F). One thin ornamented partial hypoplastron (Fig. 70A, B)
was found among more than 400 shell fragments collected by Lavocat in the 1950s
and referred by Gmira (1995) to the genus Araripemys as an indeterminate species (also
Cavin et al. 2010). is partial plastron element, however, is insucient for generic or
specic assignment within Araripemydidae, as there are no features that allow reference
to Araripemys, a genus based on material from earlier Aptian-Albian deposits in Brazil.
Specimens referable to Araripemys are limited to those from the Araripe Basin of Brazil
(Ganey et al. 2006).
In a similar manner, Broin (1980) erected a new genus and species, Taquetochelys
decorata, on the basis of a hypoplastron fragment from the Aptian-Albian Elrhaz for-
mation of Niger (Sereno and ElShae 2013: g. 14 B, C). It is less complete than
the hypoplastron from the Kem Kem araripemydid. Broin listed ten additional shell
fragments as paratypes and cited (with uncertain status) an additional 31 shell pieces.
is material was surface collected from a region known as Gadoufaoua during four
expeditions in the 1960s and early 1970s. ere is no specic type locality cited, and
the material is surely derived from many individuals.
e diagnosis oered by Broin (1980: 42) for Taquetochelys decorata was inadequate
at the time it was coined: “Pleurodire à carapace décorée de très petites granulalions et
bourrelets, serrés. Petits mésoplastrons latéraux, courts”. She tried to dierentiate the
species on details of its beaded decorative pattern and the presence of a mesoplastron,
which she inferred from the beveled margin of the hypoplastron. Neither are diagnos-
tic at the generic or species level, as pointed out by Ganey et al. (2006: 111). e
general form of decoration is similar between Nigerien and Brazilian specimens, and
the presence of a mesoplastron is a primitve feature, its loss diagnostic for Araripemys
(Sereno and ElShae 2013).
A nearly complete, articulated skeleton with a skull was later described from the
Elrhaz Formation as Laganemys tenerensis (Sereno and ElShae 2013), its diagnosis
including more than 20 autapomorphies in the skull and postcranial skeleton. ese
features clearly distinguish this taxon from the contemporary Brazilian genus and spe-
cies Araripemys barretoi, its diagnosis also revised. e hypoplastron of the holotypic
specimen of L. tenerensis also exhibits several shape and ornamentation dierences to
the hypoplastron originally described as Taquetochelys decorata (Sereno and ElShae
2013: g. 14.14). Sereno and ElShae (2013) came to the same conclusion as Ganey
et al. (2006), that the material upon which Taquetochelys decorata is based is insucient
and should be regarded as a nomen dubium.
Kem Kem Group of Morocco 89
More recently Pérez-García (2017, 2018) has attempted to resurrect Taquetochelys
decorata and reduce Laganemys tenerensis as a junior synonym by arguing that the dif-
ferences cited between their hypoplastra fall within an acceptable range of individual
variation. Pérez-García stated that “the anterior margin of the hypoplastron” was bro-
ken away, rendering ineective any shape dierences based on this bone. But our ex-
amination and specimen gures of the element show it as complete anteriorly (Pérez-
García 2018: g. 1O; see also Broin 1980: pl. III, g. 10), and the anterior margin was
cited for evidence of the presence of a mesoplastron.
Fragmentary holotypic specimens without diagnostic features lend themselves to
subsequent taxonomic ambiguity. At no point has any author oered a revised diag-
nosis of T. decorata based solely on the holotypic partial hypoplaston or even on the
numerous additional shell pieces referred to this taxon by Broin (1980). e material
associated with Taquetochelys decorata consists entirely of isolated shell fragments that
lack diagnostic features and specic locality data. Although this material is generally
consistent with the nearly complete holotype skeleton of Laganemys tenerensis, there
is no solid basis for regarding them as the same taxon. Ganey et al. (2006: 111)
remarked that it is impossible to diagnose T. decorata on the basis of the holotypic
plastron piece. We agree and regard Taquetochelys and T. decorata as nomina dubia, the
material referable to the Araripemydide on the basis of its ornamentation and several
other familial synapomorphies (Sereno and ElShae 2013: 219).
We anticipate eventual recovery of more complete araripemydid remains from the
Kem Kem Group. More complete remains may resolve its taxonomic distinction and
its anities with the slightly older African and South American genera, Laganemys and
Araripemys, respectively.
Euraxemydidae Ganey et al., 2006
Dirqadim schaeeri Ganey et al., 2006. Dirqadim schaeeri from the Kem Kem
Group is closely related to the slightly older and more completely preserved Euraxemys
esswini from the Santana Formation in Brazil (Ganey et al. 2006). D. schaeeri is
known from two crania, one of which is nearly complete (Fig. 73H-J), both of which
were commercially collected from unknown locations. Currently no postcranial mate-
rial from the Kem Kem Group can be referred to the family, genus or species. A few
features of the shell are diagnostic for Euraxemys esswini (Ganey et al. 2006: 40) and
may eventually allow reference of more complete shell material from the Kem Kem
Group to D. schaeeri.
Podocnemidoidea Cope, 1868
Hamadachelys Tong & Buetaut, 1996. Hamadachelys escuilliei (Tong and Buetaut
1996) is known from a well-preserved cranium and mandible. A second mandible
was referred to this species (Ganey et al. 2006: g. 251). All of this material was
collected commercially from unknown localities in the Kem Kem Group. e diag-
nostic features of H. escuilliei are in need of revision in light of the signicant cranial
material discovered and described since this taxon was named. e narrow interor-
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
90
bital distance in dorsal view of the cranium (Tong and Buetaut 1996) more closely
resembles Euryaxemys from Brazil than the contemporaneous genera Dirqadim and
Galianemys. Postcranial material cannot be reliably referred to Hamadachelys escuil-
liei. Hamadachelys has been positioned phylogenetically between euryaxemydids and
Galianemys at the base of the podocnemidoid radiation (Ganey et al. 2006, 2011).
Galianemys Ganey et al., 2002. e podocnemidoid Galianemys is the best
known turtle in the Kem Kem Group and is represented by several nearly complete
and partial crania (Ganey et al. 2002). Two species were named, G. whitei and G.
emringeri, with several specimens referred to one or the other species. We gure two
additional crania here (Fig. 73A -G), the more complete of which was commercially
collected and is referable to Galianemys whitei (Fig. 73A-D). e prefrontal-frontal
suture is straight rather than posteriorly convex (Fig. 73A), the jugal is separated from
the posterior orbital margin by signicant maxilla-postorbital contact (Fig. 73A), and
the jugal contacts the palatine on the posterolateral aspect of the palate (Fig. 73B).
ese are diagnostic characters that dierentiate this species (Ganey et al. 2006). Un-
like Dirqadim, another pleurodire from the Kem Kem Group (Ganey et al. 2006),
the triturating surface on the maxilla expands posteriorly assuming a broad tringular
shape in ventral view (Fig. 73B), only minor ventral embayment is present along the
jugal-quadratogugal margin in lateral view (Fig. 73D), and the U-shaped temporal
emargination along the posterior margin of the skull roof is quite deep in dorsal view
(Fig. 73A).
e second, less complete cranium (Fig. 73E-G), discovered in 2008 by a local in
the Douira Formation at Aferdou N’Chaft east of Taouz (Fig. 9, locality 14), is refer-
able to the genus Galianemys by the depth of the U-shaped posterior temporal emar-
gination. Missing portions of the cranium, however, prevent assignment to a particular
species.
Two very similar shell types, tentatively referred to Galianemys by Ganey et al.
(2006: gs 271–274), are based on nearly complete specimens of large size (carapace
length approximately 55 cm) that were collected commercially from the Kem Kem
Group. More recently Cavin et al. (2010) reported that these two shells were found
at Tizi Tazguart, a locality south of Jbel Zireg (Fig. 9, locality 9) and near another site
that yielded some 30 turtle shells that remain at large. Cavin et al. (2010) regarded the
two large shell types as condently referable to Galianemys, and Karl (2010: g. 1) ten-
tatively referred them to the two species, G. whitei and G. emringeri. No evidence has
been forwarded, however, to justify these referrals, as there currently exists no clear as-
sociation of cranial and postcranial remains for any testudines in the Kem Kem Group.
A partial carapace, complete plastron and associated pectoral and pelvic girdles of
a fairly large testudine (Fig. 72) was collected in 1995 from a site near our section at
Oum Tkout in the Douira Formation. e Douira Formation is approximately 100
m in thickness in this region, and the associated shell and girdle material was found
approximately 28 m above the rst substantial mudstone at the base of the formation.
It matches one of the shell types described by Ganey et al. (2006: g. 274) and Karl
(2010: g. 1.2). On the plastron, the intergular scute is broad and equal in transverse
Kem Kem Group of Morocco 91
width to adjacent gular scutes, a plastral scute pattern attributed without justication
to G. whitei (Karl 2010: g. 1.2). e carapace measures 31 cm in length (Fig. 72), or
approximately 56% the size of the specimens described by Ganey et al. (2006). ese
shell types may pertain to Galianemys and its two closely related species, although that
needs to be established by specimens associating cranial and shell material. At present
the single specimen we gure here (Fig. 72) is the only one that provides any evidence
of association for Kem Kem Group testudines, in this case between shell and non-shell
postcranial bones.
Squamata, Oppel, 1811
In recent years, fossil discoveries have brought to light jaw fragments and, more rarely,
nearly complete skeletons of extinct genera positioned as stem taxa to extant squamate
clades. For Iguania and Ophidia, in particular, new fossils from circum-Tethyan sites
have drawn their stem lineages back to the Early Cretaceous and, in some cases, to the
Early Jurassic (Evans et al. 2002, Hsiang et al. 2015, Caldwell et al. 2015, Martill et al.
2015, Simões et al. 2017).
From Morocco more specically, fragmentary squamate material was rst reported
in abundance from the Early Cretaceous site Anoual (Broschinski and Sigogneau-Rus-
sell 1996). e Kem Kem Group, thus far, has yet to yield abundant isolated vertebrae
or more complete remains of squamates, respectively, from sediment screening or the
pond locality Oum Tkout. Squamate remains consist of rare, isolated jaw fragments
and vertebrae pertaining to stem acrodont iguanians, borioteiioids, and ophidians.
Iguania Cope, 1864
Acrodonta Cope, 1864
Jeddaherdan. A jaw fragment with blunt, unornamented, imbricate crowns that are
ankylosed to the dentary was described as Jeddaherdan aleadonta, a new acrodont igua-
nian with potential anities with uromasticine agamids (Apesteguía et al. 2016a). It
was collected approximately 70 years ago by French paleontologist René Lavocat from
a locality (Gara Tabroumit) southwest of Gara Sbaa. e horizon remains unknown.
e only other fossil discovered so far pertaining to a squamate is a single trunk verte-
bra from Taouz of indeterminate relationship (Rage and Dutheil 2008).
Ophidia Brongniart, 1800
Norisophis. More than 100 ophidian vertebrae were recovered from eld work in the
Kem Kem Group between 1995 and 2018. ey were found at sites in both forma-
tions, with several recovered at the pond locality Oum Tkout in the Douira Forma-
tion (Rage and Dutheil 2008). More recently, isolated vertebrae were also found in
the Gara Sbaa Formation at Aferdou N’Chaft and nearby localities pertaining to
Norisophis begaa, a new basal snake (Klein et al. 2017). Centrum length is a little
more than 5 mm.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
92
Lapparentophiidae Hostetter, 1959
Lapparentophis. Vullo (2018) described two moderately elongate mid-trunk ver-
tebrae from near Begaa (close to Taouz), naming a new species in the genus Lapparen-
tophis, L. ragei, which was known previously from Algeria. e diameter of the neural
canal is much smaller than that of the cotyle, which is slightly broader than high.
Centrum length is a little more than 1 cm.
Simoliophiidae Nopcsa, 1925
Simoliophis. Rage and Dutheil (2008) referred isolated vertebrae to Simoliophis cf.
lybicus (Fig. 68E, F). ey were found in both formations at several localities including
Taouz, Oum Tkout, Douira and Dar El Karib. Two simoliophiid sacral vertebrae were
also identied from Taouz and Oum Tkout localities that show similarities to the sacral
vertebrae of snakes with hind limbs (Caldwell and Lee 1997, Rage and Escuillé 2000,
Apesteguía and Zaher 2006).
Nigerophiidae Rage, 1975. Rage and Dutheil (2008) referred 18 dorsal vertebrae
to this extinct aquatic snake family, which has been recorded from circum-Tethyan
sites of Late Cretaceous and Paleocene age (Rage and Werner 1999). e dorsal centra
are elongate and transversely narrow with tall, anteroposteriorly short neural spines.
Madtsoiidae Hostetter, 1961. Rage and Dutheil (2008) referred some 20 ophid-
ian vertebrae from Taouz and Oum Tkout to this diverse extinct family, the neural
arches characterized by a pair of parazygantral foramina on the posterior aspect of the
neural spine and the absence of prezygapophyseal processes (Wilson et al. 2010). Rage
and Dutheil (2008) regarded these Kem Kem vertebrae as distinct from the similar-
sized matsoiid snake recorded from roughly coeval Cenomanian age rocks in Sudan
(Werner and Rage 1994). ese snakes grew to modest adult size with dorsal centra
approximately 5 mm in length.
Crocodyliformes Hay, 1930
e Kem Kem Group has yielded a diverse array of crocodyliforms in size and troph-
ic adaptations, ranging from small insectivorous or herbivorous candidodontid and
sphagesaurid notosuchians less than 1 m in body length to large carnivorous neosuchi-
ans approaching the 12-meter length of Sarcosuchus (Broin and Taquet 1966, Sereno et
al. 2001). Long-snouted crocodyliform fossils discovered in the late 1940s were initial-
ly assigned to the genus oracosaurus (Lavocat 1955), a eusuchian genus known only
from North America and Europe (de Lapparent de Broin 2002). Later it was given a
new genus Elosuchus, as E. cheriensis (de Lapparent de Broin 2002, Young et al. 2017,
Meunier and Larsson 2017). A braincase of this genus and species was erroneously
referred to Libycosuchus (Buetaut 1976), a very dierent short-snouted crocodyliform
from the contemporaneous Bahariya Formation of Egypt (Stromer 1914).
By the 1990s, considerable new crocodyliforms fossils came to light in commercial
collections (e.g., Russell 1996) and in the course of eld work (Sereno and Larsson
2009). Based on fragmentary material, Buetaut (1994) named Hamadasuchus rebouli,
Kem Kem Group of Morocco 93
a peirosaurid crocodyliform. Larsson and Sues (2007) later described and attributed
a complete cranium to this genus and species. Sereno and Larsson (2009) named a
notosuchian, Araripesuchus rattoides, and a stomatosuchid, Laganosuchus maghrebiensis,
on the basis of partial dentaries of distinctive form. A single elongate distal caudal ver-
tebra was initially described as pertaining to a new neotheropod dinosaur, Kemkemia
auditorei (Cau and Maganuco 2009), which was soon regarded as a nomen dubium
after its close resemblance to the distal caudals of extant crocodilians became apparent
(Lio et al. 2012). Derived notosuchian teeth came to light in screen-washed sediment
(Larsson and Sidor 1999), and more recently a small notosuchid with multicuspid
crowns was named Lavocatchampsa sigogneaurussellae (Martin and de Lapparent de
Broin 2016). We review Kem Kem Group crocodyliforms below, a group that will
likely increase in diversity with the continued recovery of new specimens.
Notosuchia Gasparini, 1971
Uruguaysuchidae Gasparini, 1971
is family of notosuchians, united as a clade in some analyses (e.g., Leardi et al.
2015), includes the genera Anatosuchus, Uruguaysuchus and Araripesuchus.
Araripesuchus. e speciose genus Araripesuchus, known initially from South
America and later from Africa and Madagascar, also occurs in the Kem Kem Group as
Araripesuchus rattoides (Fig. 74). It was named on the basis of a partial, edentulous den-
tary with 14 alveoli that was collected commercially and thus comes from an uncertain
locality and horizon (NMC 41893, as CMN 41893 in Sereno and Larsson 2009). Re-
ferred specimens include partial dentaries from the Douira Formation collected at Dar
El Karib (near Erfoud) and another collected commercially from an uncertain locality
and horizon (BSPG 2008 I 41, Fig. 74E, F).
BSPG 2008 I 41 preserves dentary teeth 2–6 and 10 and the roots of dentary teeth
11 and 12. e socket for the rst dentary tooth projects anteriorly and presumably
held a procumbent and slightly enlarged tooth, a diagnostic feature for the species.
As in Araripesuchus wegeneri, the fourth dentary tooth is enlarged, whereas dentary
teeth 3, 5, and 6 are smaller and subconical. e alveoli for dentary teeth 9 and 10 are
incompletely separated, and dentary tooth 10 has a labiolingually compressed crown
with its carina and apex rounded by tooth abrasion as occurs in A. wegeneri (Sereno
and Larsson 2009).
A. rattoides does appear to be distinct from A. wegeneri, which is much better
known from complete skulls and skeletons from the older (Aptian-Albian) Elrhaz For-
mation in Niger. Compared to the latter, many of the dentary alveoli are exposed in
lateral view of the best-preserved dentary of A. rattoides (Fig. 74A) with the dentary
symphysis held in a vertical plane. In dorsal view with the symphysis in a sagittal plane,
the skull appears to be proportionately narrower than a comparable view of the dentary
in A. wegeneri (Sereno and Larsson 2009). Specimen BSPG 2008 I 41 (Fig. 74E, F) is
identical in form but slightly larger than the holotype of A. rattoides. Dierences in the
exposure of the alveoli as gured here are due to the orientation of the specimen when
photographed (the dentary symphysis tipped from a vertical plane).
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
94
Figure 74. Specimens referred to Araripesuchus rattoides from the Kem Kem Group. NMC 41893 in (A)
right lateral, (B) medial, (C) dorsal (occlusal) and (D) anterior view. BSPG 2008 I 41 in (E) left lateral
and (F) dorsomedial view. Scale bars equal 3 cm in A-C, E and F, and 1 cm in D.
Candidodontidae Carvalho et al., 2004
is derived family of small notosuchians, rst described by its namesake genus Candi-
dodon from Brazil (Carvalho and Campos 1988), now is well known from Early Creta-
ceous genera from east Africa, such as Malawisuchus and Pakasuchus (O’Connor et al.
2010). Candidodontidae forms a clade in some phylogenetic analyses of notosuchians
(O’Connor et al. 2010). In other analyses Candidodon and allies are positioned as basal
outgroups to Notosuchus and other notosuchians including sphagesaurids (e.g., Pol et
al. 2014, Leardi et al. 2015).
Lavocatchampsa. Recently a commercially collected partial skull from the Kem
Kem Group was described as Lavocatchampsa sigogneaurussellae (Martin and de Lap-
parent de Broin 2016). Its complex, multicuspid crown morphology includes a labial
and lingual cingulum reminiscent of that in the molariform teeth of Cretaceous mam-
maliaforms. Other derived features include the absence of a caniniform tooth. Un-
like Notosuchus and close relatives, masticatory movement appears to have been orthal
rather than propalinal. e relationships of Lavocatchampsa within Candidodontidae
are uncertain. It has been resolved as the sister group to the somewhat older genera Ma-
lawisuchus and Pakasuchus (Martin and de Lapparent de Broin 2016). Lavocatchampsa
also resembles Adamantinasuchus (Nobre and Carvalho 2006) from the slightly young-
er Adamantina Formation of Brazil.
Notosuchia indeterminate. Small multicuspid crocodyliform teeth from the
Douira Formation were rst reported by Larsson and Sidor (1999). ey were dis-
Kem Kem Group of Morocco 95
covered in a clay-rich horizon immediately beneath the fossiliferous pond deposit at
Oum Tkout. Two tooth forms were described, both of which dier from the crown
morphology in Lavocatchampsa (Martin and de Lapparent de Broin 2016). In the rst
tooth form, the crowns are subtriangular in labiolingual views and have a major row of
cusps anked by lower parallel rows to each side (UCRC VP155, VP156), as gured
in Larsson and Sidor (1999: g. 2, as SGM-Rep 4, -Rep 5). e crown shape, apical
row of cusps, and accessory cusp rows resemble the molarifom crowns in Candidodon
(Pol et al. 2014), Adamantinasuchus (Nobre and Carvalho 2006) and the Bolivian no-
tosuchian Yacarerani (Novas et al. 2009). e rst tooth form, however, is distinctive
in the variable size and location of the cusps and its pattern of tooth-to-tooth abrasion.
A large, low-angle, planar wear facet truncates one of the crowns (Larsson and Sidor
1999: g. 2D), which diers from the wear pattern present in Lavocatchampsa (Martin
and de Lapparent de Broin 2016).
In the second tooth form (UCRC VP157) described by Larsson and Sidor (1999:
g. 3, as SGM-Rep 6), multiple cusp rows also occur, but the crown has a more
rounded prole than in many notosuchians such as Malawisuchus (Gomani 1997).
e crown is ovate in occlusal view with a main cusp and several accessory cusps ori-
ented along the major axis. e main cusp is located at the extreme mesial or distal end
of the crown, rather than a central location, assuming the major axis of the crown is
mesiodistal. Grossly similar to the second tooth form are ovate crowns with few cusps
and an unusual texture of vertical striations pertaining to an unnamed notosuchian
from Upper Cretaceous rocks in Brazil (Montefeltro et al. 2009). e second tooth
form from the Kem Kem Group, however, diers in a number of regards as noted by
Montefeltro et al. (2009) and cannot be assigned to any currently known notosuchian.
ese tooth forms suggest that there exists a greater diversity of small notosuchians in
the Kem Kem Group than are currently recognized.
Peirosauridae Gasparini, 1982
Peirosaurids are a diverse and loosely united group of crocodyliforms lying outside
Neosuchia. Some authors have united peirosaurids and sebecids as Sebecia outside
Notosuchia (Larsson and Sues 2007, Sereno and Larsson 2009, Meunier and Larsson
2017), whereas others have positioned peirosaurids and sebecids as independent clades
within Notosuchia (Leardi et al. 2015, Fiorelli et al. 2016). Adding to this lack of reso-
lution are studies that name new taxa on the basis of fragmentary cranial remains from
the Kem Kem Group, which include the holotypic specimen of Hamadasuchus rebouli
(Buetaut 1974) and a partial braincase referred initially to the Egyptian genus Lybi-
cosuchus (Buetaut 1976). Further confusion has ensued with the use of the poorly de-
ned taxon Trematochampsidae, to which peirosaurids have sometimes been assigned.
Neither its namesake genus and species Trematochampsa taqueti, which was based on
isolated fragments from Niger (Buetaut 1976), nor the Family Trematochampsidae
Buetaut 1974 appear to be valid (Meunier and Larsson 2017).
In 2007 a suite of commercially collected material was described and referred to
H. rebouli, including a nearly perfect adult cranium (ROM 52620, Fig. 75), braincases
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
96
(ROM 54511, 52059), a dentary (ROM 49282) as well as more fragmentary subadult
specimens (Larsson and Sues 2007). e more gracile dentary diers in several regards
from MDEC001. In dorsal view, the rst three alveoli are more mesially positioned rel-
ative to the fourth alveolus given the sharper median convergence of the dentary rami.
e fourth and thirteenth alveoli are largest, with a more dramatic increase in diameter
from the eleventh alveolus. e splenial bounds the eleventh and more distal alveoli.
Hypertrophied alveolar bone is not present either medially or laterally, and no groove
is present. ese dierences render it dicult to refer the dentary or other material to
H. rebouli. is assignment also was questioned by Cavin et al. (2010: 398), although
no justication was provided. ey also questioned referral to H. rebouli by Larsson
and Sues (2007) of the braincase (MNHN-MRS 3101, Fig. 76C) initially identied as
Libycosuchus by Buetaut (1974). Yet, this specimen is clearly closer in morphology to
the supratemporal fossa of ROM 52620 (Fig. 75; Larsson and Sues 2007) than to the
holotypic specimen of the short-snouted Egyptian crocodyliform Libycosuchus breviro-
stris (BSP 1912 VIII 574-578, Figs 77A, F, 78).
More recently, a nearly complete skull and lower jaws were commercially col-
lected from the Kem Kem Group and have yet to be described in detail (BSPG 2005
I 83, Rauhut and López-Arbarello 2006). At just more than 30 cm in length (Fig.
79), it is almost the exact same size as the previously described perfect cranium (Fig.
75) and, likewise, was referred to H. rebouli. We see little reason to doubt the assign-
ment to H. rebouli of the new skull (BSPG 2005 I 83, Fig. 79) as well as a suite of
more fragmentary material from the Kem Kem Group (Figs 80–82). One braincase
was collected from the Gara Sbaa Formation at Aferdou N’Chaft and represents the
only partial skull of H. rebouli from a known horizon and locality (FSAC-KK 930,
Fig. 81A, B). Another specimen that was commercially collected from an unknown
horizon and locality preserves the edentulous, fused dentary-splenial symphysis
from an adult skull (CMN 41784, Fig. 82D-F). e description of the new com-
plete skull BSPG 2005 I 83 should carefully rene the diagnostic characters listed
for this genus and species based on the rst complete cranium (Larsson and Sues
2007: 534). With that knowledge, many isolated cranial specimens may be referred
with greater justication.
Neosuchia Clark, 1988
Stomatosuchidae Stromer, 1925
is derived family of moderate to large-sized crocodyliforms was rst described as
Stomatosuchus inermis from the likely Cenomanian-age Bahariya Formation of Egypt
(Stromer, 1925). e nearly 2 m long at cranium of the holotype was found in articu-
lation with a very slender U-shaped mandible (Sereno and Larsson 2009). is iconic
crocodyliform became all the more enigmatic when the holotype and only known
specimen was destroyed in WWII. e lack of material has rendered uncertain the
position of Stomatosuchidae within Crocodyliformes. As discussed below, the pos-
sible association of vertebrae with procoelous centra with this skull type suggests that
Stomatosuchidae may fall within Neosuchia.
Kem Kem Group of Morocco 97
Figure 75. Sebecid skull, referred to Hamadasuchus rebouli (ROM 52620) in (A) left lateral, (B) dorsal
and (C) ventral views (from H.-D. Sues; Larsson and Sues 2002). Scale bar equals 10 cm. Abbreviations:
f frontal m maxilla n nasal pl palatine pm premaxilla pt pterygoid q quadrate qj quadratojugal.
Laganosuchus. Recently remains of a similar crocodyliform surfaced in the Echkar
Formation of Niger (Sereno and Larsson 2009). is material was described as La-
ganosuchus thaumastos (Fig. 83A, B). A similar species, named L. maghrebensis, was
described from dentary fragments from the contemporaneous Kem Kem Group (Fig.
83C-K; Sereno and Larsson 2009).
e holotype (UCRC PV2, Fig. 83C-E) preserves the rst four alveoli, the rst
opened to fully expose an erupting crown. e tapering crown lacks recurvature and
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
98
Figure 76. Other sebecid cranial specimens. Posterolateral skull roof (FSAC-KK 930) in (A) dorsal and
(B) right lateral view. Partial braincase of Hamadasuchus rebouli (MNHN-MRS 3101) in (C) dorsal view
(initially referred to Libycosuchus, Buetaut 1994). Scale bars equal 10 cm in A and B, 5 cm in C.
exhibits light uting on its lingual side. A referred specimen (NMC 50838, Sereno and
Larsson 2009, Fig. 83I-K) preserves a similar portion of the anterior dentary ramus
and also includes an erupting tooth in what appears to be the third alveolus. e tooth
is approximately 17 mm in height and curves slightly distally at its tip. A second re-
ferred specimen with a fully erupted crown may also pertain to L. maghrebensis (NMC
41786, Fig. 84).
A larger dentary piece of L. maghrebensis was gured by Rauhut (2009), compris-
ing the anterior portion of the left dentary and fused symphyseal end of the right
dentary (Fig. 83F-H). e rst alveolus contains a fully erupted caniniform crown fol-
lowed by 10 empty alveoli (BSPG 2008 I 62, Fig. 83F-H). e dentary ramus thickens
toward the symphysis, unlike the other smaller specimens of the species (Fig. 83D, G,
J). A thickened symphyseal shelf was described as diagnostic of L. thaumastos (Sereno
and Larssson 2009). Given the larger size of BSPG 2008 I 62, symphyseal thickening
may occur with maturity. As in L. thaumastos (Sereno and Larsson 2009), the rst, sec-
ond and fourth alveoli are larger than the others (Fig. 83G). Unlike L. thaumastos, the
more distal alveoli are closely spaced (Fig. 83A, G). In L. thaumastos, in contrast, the
alveoli distal to the fourth are all well separated, except for the sixth and seventh (Fig.
83A). In addition, the alveoli in L. thaumastos are separated by an undulating margin
that exposes the alveolar rim in lateral view (Fig. 83A). e more complete dentary of
L. maghrebensis (BSPG 2008 I 62) conrms the original assessment that Moroccan and
Nigerien specimens represent distinct species.
Aegisuchus. Aegisuchus witmeri was named on a commercially collected braincase
of uncertain locality in the Kem Kem Group (ROM 54530, Holliday and Gardner
2012). is specimen closely resembles the braincase of Aegyptosuchus peyeri (Stromer
1933) from the Bahariya Formation of Egypt (Fig. 85). Although the braincase of
Aegyptosuchus peyeri survived WWII, associated procoelous vertebrae suggestive of neo-
suchian relationships were destroyed (Stromer 1933).
Kem Kem Group of Morocco 99
Figure 77. Original material of Libycosuchus brevirostris Stromer, 1914 (BSP 1912 VIII 574-578). Cra-
nium in (A) dorsal, (B) ventral (C) left lateral view. Lower jaw in (D) dorsal and (E) ventral view. Skull
in (F) dorsolateral view. ?Sacral vertebra in (G) lateral view. Caudal vertebra in (H) anterior and (I) lateral
view. Scale bars equal 10 cm in A-E, 3 cm in G-I.
Striking features of the braincase link Aegisuchus and Aegyptosuchus, which Holli-
day and Gardner (2012) placed in Aegyptosuchidae on the basis of several cranial char-
acters. In dorsal view, the orbits are very closely spaced, and supratemporal fossae are
small, widely separated, and displaced anteriorly, and the occipital surface is broadly
exposed in dorsal view (Fig. 85). e skull roof between the dorsally facing orbits is
particularly narrow, the medial margin of each orbit closer to the midline than the me-
dial rim of the supratemporal fossa. e quadrate shafts are very broad and posteriorly
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
100
Figure 78. Comparison of the braincases – in dorsal view – of the small crocodyliforms (A) Libycosuchus
brevirostris, (B) sebecid indet. (FSAC-KK 08) and (C) a specimen initially referred to Hamadasuchus re-
bouli (MNHN-MRS 3101). Specimens adjusted to similar size (see Figs 76, 77 and 81 for scale in A-C).
Figure 79. Skull of Hamadasuchus rebouli (BSPG 2005 I 83, Rauhut & López-Arbarello, 2006) in (A)
lateral and (B) dorsal view (see). Scale bar equals 5 cm.
angled, indicating that the skull is quite dorsoventrally compressed. As reconstructed
by Holliday and Gardner (2012: g. 1), the cranium quite possibly was very low and
elongate as in Stomatosuchus inermis.
All of these features, nevertheless, appear to be present in Stomatosuchus inermis,
the braincase of which was only partially preserved (Stromer 1925, Sereno and Larsson
2009). e Egyptian Aegyptosuchus peyeri, thus, might constitute a junior synonym of
Stomatosuchus inermis from the same formation. We are unable to dierentiate the two
Kem Kem Group of Morocco 101
Figure 80. Sebecid upper jaw bones from the Kem Kem Group. Partial left maxilla (NMC 41866) in
(A) lateral and (B) medial view. Partial left premaxilla (NMC 41892) in (C) anterolateral and (D) medial
view. Maxillary fragment (FSAC-KK 932) in (E) lateral, (F) medial and (G) ?anterior view. Base of the
maxillary crown (FSAC-KK 932) in (H) lateral view. Scale bar equals 3 cm in A-G, 1 cm in H.
on the basis of available images of Stomatosuchus inermis. e family Aegyptosuchidae,
in turn, might well be redundant with Stomatosuchidae. Among the Moroccan speci-
mens, there is no overlap between the braincase of Aegisuchus witmeri and the dentary
sections of Laganosuchus maghrebiensis. Given their similar size, it is entirely possible
that more complete specimens from the Kem Kem Group will show that Aegisuchus
witmeri is a junior synonym of Laganosuchus maghrebiensis.
Pholidosauridae Zittel & Eastman, 1902
e rst specimens of a long-snouted crocodyliform discovered in the Kem Kem
Group were identied as “oracosaurus” cheriensis (Lavocat 1955). oracosaurus, a
eusuchian genus from North America and Europe, was abandoned in favor of a new
genus Elosuchus (de Lapparent de Broin 2002), which came to be known from nearly
complete crania and mandibles from Morocco, Algeria, and Niger. Given that there
are several long-snouted clades of crocodyliforms, the taxonomic status and anity of
this material, including the specimens from the Kem Kem Group, has been uncertain.
Recently, the material of Elosuchus from Morocco and Algeria was redescribed as
pertaining to two species of pholidosaurids. e Moroccan material, based on specimens
from the Kem Kem Group, was attributed to E. cheriensis, whereas the fossils from the
potentially slightly older Albian beds in Algeria (at Gara Samani, Fig. 1) were attributed
to a new species E. broinae (Meunier and Larsson 2017). e two species dier only in
minor features. e Nigerien material originally described as E. felixi was transferred to
a new genus Fortignathus and identied as a dyrosaurid (Young et al. 2017).
Elosuchus. Lavocat (1955) based “oracosaurus cheriensis on isolated croco-
dyliform bones from Gara Sbaa that were never illustrated or numbered. As most of
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
102
Figure 81. Sebecid braincases from Aferdou N’Chaft. Braincase (FSAC-KK 1237) referable to Hama-
dasuchus rebouli in (A) dorsal and (B) ventral view. Partial braincase (FSAC-KK 08) in (C) dorsal, (D)
ventral, (E, I) anterior, (F) posterior, (G) left lateral and (H) right lateral view. Scale bar equals 5 cm in
A-H. Abbreviations: bo basioccipital bsr basisphenoid recess cqp cranioquadrate passage f frontal fo ICA
foramen for internal carotid artery fo MM maxillomandibular foramen fo mAMEP Musculus adductor
mandibulae externus profundus fo V1 ophthalmic foramen oc occipital condyle p parietal q quadrate.
this material was subsequently lost, a nearly complete skull was designated as the lec-
totype for E. cheriensis (MNHN E 1, Meunier and Larsson 2017). As the skull was
commercially collected, its exact horizon and locality within the Kem Kem Group are
unknown. Features listed in a revised generic diagnosis include ve premaxillary teeth,
the rst of which is displaced posterior to the second, paddle-shaped lacrimal, strong
anterior process of the squamosal that overlaps much of the postorbital laterally, quad-
ratojugal overlapping all of the quadrate near its laterodistal condyle, and a small pit at
the anteromedial end of the dentary near the symphysis that receives the tip of the rst
premaxillary tooth (Meunier and Larsson 2017).
Kem Kem Group of Morocco 103
Using the revised diagnosis and lectotype cranium, additional specimens can be
referred to E. cheriensis, which include paired premaxillae and partial rostra (Figs
86, 87), the posterior half of crania (Fig. 88A-E), fragmentary cranial bones (Fig. 89),
mandibular rami (Figs 90, 91), and, with less condence, isolated teeth (Fig. 92). e
bones of E. cheriensis were surface collected from many sites in the Kem Kem Group.
A partial premaxilla (FSAC-KK 923, Fig. 89A-E) was surface collected in the Gara
Sbaa Formation, and an isolated jugal (FSAC-KK 09, Fig. 88F-H) and mandibular
symphysis (FSAC-KK 753, Fig. 91) were collected from the Douira Formation.
De Lapparent de Broin (2002) referred large isolated scutes to Elosuchus, but the
association of the skull remains and scutes described is unclear. Large osteoderms
have previously been attributed to “Sarcosuchus sp”. (Sereno et al. 1996), although
evidence for this specic genus is lacking in the Kem Kem Group. Two morphologi-
Figure 82. Mandibular symphyses of Hamadasuchus rebouli. Mandibular symphysis (MNHN-MRS
3110) in (A) dorsal, (B) ventral and (C) right lateral view. Mandibular symphysis (NMC 41784) in (D)
dorsal, (E) ventral, (F) left lateral, (G) anterior and (H) posterior view. Scale bar equals 3 cm. Abbrevia-
tions: ad2, 4 alveolus for dentary tooth 2, 4 d4 dentary tooth 4 fo foramen sp splenial.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
104
Figure 83. Specimens of Laganosuchus from the Echkar Formation in Niger and the Kem Kem Group in
Morocco. Cast of lower jaws (UCRC PVC9) of the holotypic specimen of L. thaumastos (MNN IGU13)
in (A) dorsal and (B) left lateral view. Holotypic specimen of L. maghrebensis (UCRC PV2) from the Kem
Kem Group in (C) left lateral, (D) dorsal and (E) ventral view. BSPG 2008 I 62 in (F) left lateral, (G)
dorsal (occlusal) and (H) ventral view. Partial dentary of L. maghrebensis (NMC 50838) in (I) lateral, (J)
dorsal (occlusal) and (K) ventral view. Scale bars equal 20 cm in A and B, 6 cm in C–K.
Kem Kem Group of Morocco 105
Figure 84. Dentary fragment with tooth referred to Laganosuchus maghrebensis (NMC 41786) in (A)
lateral, (B) medial and (C) dorsal view. Scale bar equals 2 cm. Abbreviation: d dentary.
Figure 85. Holotypic specimen of Aegyptosuchus peyeri Stromer, 1933 from the Bahariya Formation of
Egypt in dorsal (A) and ventral (B) view. Scale bar equals 10 cm.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
106
Figure 86. Cranial remains of the crocodyliform Elosuchus. A, C E. cheriensis cranium (MNHN SAM
129) in dorsal and ventral views B E.cheriensis (MNHN SAM 129) with posterior skull roof (NMC
41912) and anterior snout section (FSAC-KK 10) superimposed, D E.cheriensis premaxilla (MNHN
SAM 129), drawing in ventral view E E.cheriensis premaxilla FSAC-KK 10 F E. cheriensis occipital
piece (MNHN-MRS 340-25) G E. cheriensis lower jaw reconstructed from several specimens (MNHN-
E 43, SAM 138, SAM 137-157; redrawn from Lapparent de Broin 2002) H E.cheriensis anterior dentary
symphysis (MNHN E 43) in dorsal view I Partial dentary symphysis (MNHN-INA 25). Abbreviations:
bo basioccipital, d dentary, ex, exoccipital j jugal m maxilla pm premaxilla pt pterygoid sym symphysis.
Scale bars equal 10 cm in A-C and E-G, 20 cm in H.
Kem Kem Group of Morocco 107
cally identical isolated dentary fragments show the substantial range in size among
material attributed to E. cheriensis (UCRC PV159, CMN 41785, Fig. 89J, K).
Meunier and Larsson (2017) noted some Elosuchus material from the Kem Kem
diers from MNHN E 1, notably in the parietal bar separating the supratemporal
fenestrae. MNHN E 1 and other material they refer to E. cheriensis has a waisted
bar, whereas other specimens have a broad, sculpted bar, similar to that of E. broinae
(CMN 41912, ROM 52586, 64698, 64699). ere may be more than a single spe-
cies of Elosuchus within the Kem Kem Group (Meunier and Larsson 2017).
Neosuchia indeterminate. A large left jugal (FSAC-KK 07, Fig. 93) was found
in situ in the Douira Formation at the locality Aferdou N’Chaft (Fig. 9, locality 14).
With a preserved length of more than15 cm, the individual is approximately 150%
the size of the adult cranium described by Larsson and Sues (2007: g. 2; see also Fig.
Figure 87. Rostral fragments referred to cf. Elosuchus. Rostral fragment (FSAC-KK 10) in (A) dorsal, (B)
ventral, (C) right lateral and (D) anterior view. Rostral fragment (NMC 41866) in (E) dorsal and (F) ven-
tral view. Maxillary piece (MNHN-MRS 3111) in (G) dorsal and (H) ventral view. Scale bar equals 10 cm.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
108
Figure 88. Braincase and jugal of the crocodyliform Elosuchus cheriensis. Braincase (MNHN-MRS 3115)
in (A) dorsal and (B) ventral view. Braincase (NMC 41912) in (C) dorsal, (D) ventral and (E) left lateral
view. Jugal (FSAC-KK 09) in (F) left lateral, (G) medial and (H) ventral view. Scale bar equals 20 cm.
75A). e postorbital bar, which is smooth and inset in neosuchians, appears to be less
inset from the sculpted surface of the jugal in FSAC-KK 07 than in H. rebouli (Larsson
and Sues 2007). e posterior ramus, in addition, tapers distally and is deected medi-
Kem Kem Group of Morocco 109
Figure 89. Fragmentary bones tentatively referred to the crocodyliform Elosuchus. Left premaxilla
(FSAC-KK 923) in (A) lateral, (B) medial, (C) anterior, (D) dorsal and (E) ventral view. ?Lacrimal
(BSPG 2008 I 60) in (F) lateral and (G) medial view. Basioccipital and basisphenoid (FSAC-KK 926)
in (H) ventral and (I) posterior view. Left dentary fragment (UCRC PV168) in (J) dorsal view. K Left
dentary fragment with ve teeth (NMC 41785) in lateral view. Scale bar equals 5 cm. Abbreviations: bo
basioccipital pm4 premaxillary tooth 4.
ally (Fig. 93A, C). In H. rebouli, in contrast, the posterior process of the jugal expands
slightly in dorsoventral height and is deected slightly laterally.
Four foramina are visible on medial aspect of the body of the jugal (Fig. 93D). In
extant crocodilians, one to three foramina open into the body of the jugal for the jugal
nerve. e condition in H. rebouli is not known. Two other foramina pierce the large
jugal near the ventral margin (Fig. 93C).
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
110
Figure 90. Dentaries of the crocodyliform Elosuchus cheriensis. A Left anterior dentary (UCRC PV169)
in dorsal view B Dentary symphysis (E 44 (MNHN; Lapparent de Broin 2002) in dorsal view C, D Left
anterior dentary (NMC 41867) in dorsal and left lateral views E-H Dentary symphysis (NMC 41791) in
dorsal, ventral, right lateral and anterior view. I, J Dentary and splenial symphysis (MNHN-MRS 3112)
in dorsal and ventral view. Scale bars equal 10 cm. Abbreviations: pm1 premaxillary tooth 1 sp splenial.
Kem Kem Group of Morocco 111
Figure 91. Mandibular symphysis of the crocodyliform Elosuchus cheriensis. Right anterior dentary
(FSAC-KK 753) in (A) dorsal, (B) ventral, (C) right lateral, (D) medial and (E) anterior view. Recon-
structed symphysis of Elosuchus cheriensis using reected image of FSAC-KK 753 in (F) dorsal and (G)
ventral view. Scale bar equals 5 cm in A-D, F and G, and 2 cm in E. Abbreviations: d6, 12 dentary tooth
6, 12 sp splenial.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
112
Figure 92. Isolated pholidosaurid crocodyliform teeth. A NMC 41791 (see Fig. 88E) B-D BSPG 1993
IX 334 E MNHN-MRS 765 F MNHN-MRS 766 G MNHN-MRS 767. Scale bar equals 3 cm.
Pterosauria Kaup, 1834
Although not recognised as pterosaurian at the time, the rst pterosaur remains to be
recovered from the Kem Kem Group consisted of isolated teeth collected by Lavocat in
the late 1940s and early 1950s and now in the MNHN collections. Isolated, recurved,
striated pterosaur teeth, likely ornithocheirid in most cases, are fairly common in these
deposits. Kellner and Mader (1997: g. 4) were the rst to gure one of these teeth,
four distinct morphotypes were described by Wellnhofer and Buetaut (1999: gs
6–10) and additional examples are gured here (Fig. 94).
e rst remains to be condently identied as pterosaurian, an elongate mid-
cervical vertebra referred to the Azhdarchidae, was described in a short abstract by
Kellner and Mader (1996) and later gured by Rodrigues et al. (2011: g 4). e
following year, in another abstract, Mader and Kellner (1997) briey described a jaw
fragment with teeth (LINHM 016, Fig. 95A, B). Formally described by these authors
in 1999, this specimen formed the holotype of Siroccopteryx moroccensis, a colobo-
rhynchine, and the rst pterosaur to be named from the Kem Kem Group. Recently,
Jacobs et al. (2019) named a second coloborhynchine from the Kem Kem Group,
Coloborhynchus uviferox, and reported jaw fragments attributable to Anhanguera sp.
and Ornithocheirus sp. (Jacobs et al. 2020).
Wellnhofer and Buetaut (1999) published the rst direct evidence for edentulous
pterosaurs in the Kem Kem group. is included a well preserved but fragmentary
rostrum (BSP 1993 IX 338, Fig. 96A-E) identied as pteranodontid, a fragment of a
mandibular symphysis bearing a deep ventral crest (BSP 1997 I 67, Fig 97), identied
as tapejarid and an elongate, lance-shaped fragment of a mandibular symphysis (BSP
1996 I 36; Wellnhofer and Buetaut 1999: g. 4) identied as azhdarchid. e latter,
and BSP 1993 IX 338, were subsequently assigned to Alanqa saharica (Fig. 96; Ibra-
him et al. 2010). Recently, however, BSP 1993 IX 338 has been reassigned to a new
chaoyangopterid from the Kem Kem Group (McPhee et al. 2020) e identication of
BSP 1997 I 67 as tapejarid is supported by the recent discovery of further tapejarid jaw
material in the Kem Kem Group (Martill et al. 2020). Kellner et al. (2007) described
Kem Kem Group of Morocco 113
Figure 93. Sebecid left jugal (FSAC-KK 07) in (A) lateral, (B, D) medial and (C) ventral view. Scale bar
equals 5 cm in A–C. Abbreviations: nAD dorsal alveolar branch of the maxillary nerve (V2) nJU jugal
branch of the maxillary nerve (V2).
the fourth example of an edentulous jaw from the Kem Kem Group (MN 7054-V)
and tentatively identied is as pteranodontid.
Alanqa saharica, an azhdarchid founded on a well-preserved fragment of a man-
dibular symphysis (FSAC KK 26; Fig 98) collected in 2008, and reinterpreted here as
part of the rostrum was the rst edentulous Kem Kem Group pterosaur to be named
(Ibrahim et al. 2010). Additional remains, including fragments of the rostrum and
mandibular symphysis (Kellner et al. 2007, Ibrahim et al. 2010, Martill and Ibrahim
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
114
Figure 94. Ornithocheirid pterosaur teeth from the Kem Kem Group. A FSAC-KK 885 B FSAC-KK
44 C FSAC-KK 886 D, E FSAC-KK 197 in labial and lingual views F FSAC-KK 887 G FSAC-KK 941
H Teeth of ‘morphotype 1’ of Wellnhofer and Buetaut (1999) (BSPG 1993 IX 590-596) I Teeth of
‘morphotype 2’ of Wellnhofer and Buetaut (1999) (BSPG 1993 IX 597-607) J Teeth of ‘morphotype 3’
of Wellnhofer and Buetaut (1999) (BSPG 1993 IX 608-617) K Tooth of ‘morphotype 4’ of Wellnhofer
and Buetaut (1999) (BSPG 1993 IX 618). Scale bar equals 3 cm.
2015) and, more tentatively, cervical vertebrae (Ibrahim et al. 2010, Rodrigues et al.
2011) and a partial humerus (Rodrigues et al. 2011) have been assigned to this taxon
(Averianov 2014). A second azhdarchid, Xericeps curvirostris, founded on a fragmen-
tary, elongate, curved mandibular symphysis was described by Martill et al. in 2018
Kem Kem Group of Morocco 115
Figure 95. Ornithocheirid pterosaur jaw fragments from the Kem Kem Group. Premaxillae of Siroccop-
teryx moroccensis in (A) left lateral and (B) ventral views (from Mader and Kellner 1999). Dentary ramus
of an indeterminate ornithocheirid (FSAC-KK 33) in (C) ?left lateral and (D) ?dorsal view. Scale bars
equal 3 cm. Abbreviations: ad alveolus for dentary tooth iap interalveolar pit pm2 premaxillary tooth 2.
(Fig. 99). Following the erection of this taxon, the second azhdarchid from the Kem
Kem Group, it can no longer be automatically assumed that azhdarchid postcranial
remains from these deposits pertain only to Alanqa.
All of the Kem Kem Group pterosaur material consists of isolated, often fragmen-
tary specimens (Figs 94–102). Some originate from commercial sources and lack pre-
cise locality data. In numerical terms, teeth (Fig. 94) far outnumber skeletal remains,
with many hundreds, and possibly more than one thousand already recovered. Among
skeletal remains, fragments of the rostrum and mandibular symphysis of edentulous
pterosaurs (Figs 96–101), seemingly all azhdarchoids, outnumber all other skeletal ele-
ments described so far. e relatively common occurrence of azdarchoid jaw remains is
in sharp contrast to the comparatively rare incidence of ornithocheirid jaw fragments
which, to date, number only six examples (Mader and Kellner 1999, Jacobs et al. 2019,
2020). is disparity is perhaps due to the unusually robust construction of the jaws of
azhdarchoids in which the tips of rostra and mandibular symphyses are composed of
relatively thick cortical bone with only a small central lumen (Fig. 101D).
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
116
Figure 96. Rostral fragment (BSP 1993 IX 338) referred by McPhee et al. (2020) to a new ?chaoyangop-
terid azhdarchoid from the Kem Kem Group in (A) left lateral, (B) right lateral, (C) dorsal, (D) ventral
and (E) posterior view. Fragmentary azhdarchoid rostrum (FSAC-KK 27) in (F) left lateral, (G) right
lateral, (H) dorsal, (I) ventral and (J) posterior view. Scale bars equal 5 cm in A-E, 3 cm in F-J.
Postcranial remains including cervical vertebrae (Fig. 102; Ibrahim et al. 2010,
Rodrigues et al. 2011) and limb bones (Rodrigues et al. 2011) are relatively rare and
fragmentary, but often well preserved, undistorted and exhibit ne anatomical detail.
Recently collected material, seemingly all referable to azhdarchoids and including ad-
Kem Kem Group of Morocco 117
Figure 97. Fragment of the mandibular symphysis of a tapejarid pterosaur (BSP 1997 I 67) from the Kem
Kem Group in (A) ?left lateral, (B) ?right lateral and (C) dorsal (occlusal) view. Scale bar equals 5 cm.
Figure 98. Rostrum of Alanqa saharica (FSAC-KK 26) from the Kem Kem Group in (A) ventral and (B)
lateral views with magnied view of foramina and ventral margin. Scale bar equals 5 cm.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
118
Figure 99. Fragment, coated in ammonium chloride, of the mandibular symphysis of Xericeps curviro-
stris, Martill et al. 2018, FSAC-KK 10700 in (A) left lateral, (B), occlusal, (C), right lateral and (D), ven-
tral views. Reproduced from Martill et al. 2018. Abbreviations: os occlusal surface aos accessory occlusal
surface l fo lateral foramina vs ventral sulcus. Scale bar equals 50 mm.
ditional cervicals, forelimb elements (humerus, ulna, wing-metacarpal, wing-phalan-
ges), and hind limb elements (femur, tibia), has yet to be described.
Ornithocheiroidea Seeley, 1891
Ornithocheiridae Seeley, 1870
Siroccopteryx. Siroccopteryx moroccensis Mader & Kellner, 1999, based on the anterior
portion of a rostrum that retains teeth (LINHM 016, Fig. 95A, B), was found near
Begaa, a village close to the north end of the Kem Kem Hamada, according to the
private collector involved in the sale of the material (Mader and Kellner 1999). e
holotype, bearing the anteriomost six pairs of teeth, consists of coossied premaxillae
and possibly a small portion of the anterior ends of the maxillae. e original descrip-
tion (Mader and Kellner 1999) has been supplemented by additional observations in
more recent studies (Unwin 2001, Veldmeijer 2003, Rodrigues and Kellner 2008). e
anterior prole measures approximately 30 mm in width at the base and has a height,
Kem Kem Group of Morocco 119
Figure 100. Fragments of jaws of a ?chaoyangopterid pterosaur from the Kem Kem Group. FSAC-KK
29 in (A) left lateral, (B) ?dorsal, (C) anterior and (D) posterior views E Detailed view of anterior-most
paired foramina. FSAC-KK 32 in (F) left lateral, (G) ?dorsal and (H) posterior view. UCRC PV161 in
(I) left lateral, (J) ?dorsal and (K) posterior view. Scale bar equals 5 cm in A-D and 4 cm in F-K. E scale
bar equals 5 mm.
to the apex, of 43 mm. A rostrum of these general dimensions corresponds in size to
large ornithocheirids with wingspans of 3–4 m (Martill and Unwin 2012).
Several authors have suggested that Siroccopteryx may be synonymous with Colobo-
rhynchus (Unwin 2001, Veldmeijer 2003, Ibrahim et al. 2010). Conversely, Rodrigues
and Kellner (2008) and Jacobs et al. (2019) have argued that it represents a genus
distinct from other ornithocheirids. LINHM 016 exhibits several distinctive features
including an unexpanded, near parallel prole, in palatal view (Fig 95B), a relatively
narrow, deep rostrum, a rounded anterior prole of the rostrum in lateral aspect (Fig
95A) and a posteriorly displaced rostral crest. In combination these characters appear
to distinguish Sirocccopteryx from coloborhynchines, typied for example by Colobo-
rhynchus clavirostris (Owen, 1874) and Uktenadactylus (Coloborhynchus) wadleighi (Lee
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
120
1994), and ornithocheirids more generally. Pending the discovery of more complete
remains, Siroccopteryx is retained here as a distinct taxon.
Coloborhynchus. Coloborhynchus uviferox Jacobs et al. 2019, based on the an-
teriormost portion of a rostrum bearing two pairs of teeth (FSAC-KK 10701), likely
from Aferdou N’Chaft, appears to represent a second ornithocheirid from the Kem
Kem Group. e holotype and only known specimen exhibits typical coloborhynchine
characters such as the development of a tall, triangular, vertically reected palatal sur-
face on the anterior termination of the rostrum, pierced by the rst pair of dental
alveoli, and a tall, narrow rostral crest that rises directly from the anteriormost tip of
this surface. is rostral fragment is somewhat larger than the holotype of Siroccop-
teryx moroccensis and, based on comparison with other more complete remains of or-
nithocheirids (Martill and Unwin 2012), likely represents a relatively large individual
at least 4 m in wingspan.
Ornithocheiridae indet. A partial mandibular ramus 160 mm in length and bear-
ing four dental alveoli was collected from Aferdou N’Chaft from the Gara Sbaa Forma-
tion (FSAC-KK 33, Fig. 95C, D). Caudal to the posteriormost dental alveolus, likely
the last in the series, the dorsal surface of the mandibular ramus is smooth and round-
ed. Small pits may have accommodated the tips of teeth located in the rostrum (cf. My-
ers 2010), and suggest that the upper tooth row extended further posteriorly than the
lower tooth row. Comparison with more complete material of Anhanguera (Wellnhofer
1985, 1991) and Coloborhynchus (Kellner and Tomida 2000, Veldmeijer 2003) suggest
that, when complete, the mandibles were approximately 600 mm in length, representa-
tive of a large ornithocheirid 4–5 m in wingspan. Until Kem Kem ornithocheirids are
better understood it is not possible to determine whether this fragment pertains to the
two named coloborhynchines, or a third ornithocheirid. Jacobs et al (2020) recently
described a mandible tip that they referred to Anhanguera. In addition, they gured
two isolated rostral tips that they referred to, respectively, Ornithocheirus and a species
of Coloborhynchus distinct from C. fulviferox.
Isolated, often incomplete, ornithocheirid teeth have been described by Kellner and
Mader (1997) and Wellnhofer and Buetaut (1999). ey are present in several collec-
tions (MNHN, UCRC, FSAC) and have been recovered by the authors from multiple
localities (Boumerade, Gara Sbaa, Zguilma, Aferdou N’Chaft, Taouz, and Jorf). Tooth
crowns often show apical wear and the absence, in many cases, of a root suggests that
many of these teeth may have been shed after some root resorption (Fig. 94).
All teeth recovered to date can be assigned to one of the four morphotypes recog-
nized by Wellnhofer and Buetaut (1999). ey include: slender and recurved crowns
with an oval cross-section near the tip (morphotype I, Fig. 94H); slender, attened,
gently recurved crowns (morphotype II, Fig. 94I); robust, wide-based, nearly straight
crowns with two carinae (morphotype III, Fig. 94C, J); and very robust, large, recurved
crowns approximately 35 mm in length (morphotype IV, Fig. 94K). Tooth morphol-
ogy and size can vary quite considerably along the tooth row in ornithocheirids (e.g.
Campos and Kellner 1985, Wellnhofer 1985, 1991, Kellner and Tomida 2000, Frey
et al. 2003, Veldmeijer 2003, Wang et al. 2012, 2014). Moreover, this variation was
Kem Kem Group of Morocco 121
likely compounded by allometric shape changes related to ontogeny, with hatchlings
of 0.3–0.4 m wingspan (Unwin and Deeming 2019) achieving sizes, at maturity, of
4 m or more, an order of magnitude larger. Even so, it is dicult to accommodate all
four tooth morphotypes within the dentition of a single ornithocheirid and it seems
likely that multiple species were present in the Kem Kem Group. is is consistent
with the recognition of four distinct genera, Siroccopteryx, Coloborhychus, Anhanguera
and Ornithocheirus, but assignment of individual teeth to these, or other Kem Kem
ornithocheirids (Jacobs et al. 2020) will require further work.
Azhdarchoidea Nessov, 1984
Tapejaridae Kellner, 1989
Tapejaridae indet. e anterior portion of an edentulous mandibular symphysis bear-
ing a large ventral crest (BSP 1997 I 67) was described by Wellnhofer and Buetaut
(1999; Fig. 97). e jaw is Y-shaped in cross-section with rami that diverge only slight-
ly posteriorly. Slit-shaped foramina are present on the external surfaces, and cancel-
lous bone is exposed on broken surfaces. e ventral crest is large and subtriangular
in shape, with a slightly concave antero-ventral margin. e fragment measures 118
mm in length and 16 mm in posterior width, with a maximum of 10 mm across the
occlusal surface. Based on comparison with more completely known tapejarids such
as Sinopterus from the Jiufotang Formation of China (Wang and Zhou 2003, Lü et al.
2006) it seems likely that BSP 1997 I 67 originally had a wingspan of around 3 m.
e morphology of the jaw and deep ventral crest corresponds well to that of tape-
jarids such as Tapejara (e.g., Vullo et al. 2012: g. 5C). By contrast other edentulous
pterosaurs either have a low mandibular crest (thalassodromeids) or none at all (pterano-
dontians, chaoyangopterids, azhdarchids) (Witton 2009, Vullo et al. 2012). Identication
of BSP 1997 I 67 as tapejarid is supported by the recent discovery, in the Kem Kem group,
of additional tapejarid material recently described by Martill et al. (2020). is new mate-
rial assigned to a new taxon, Afrotapejara zouhrii Martill et al., 2020, suggests that a frag-
mentary rostrum, MN 7054-V, described by Kellner et al. (2007: g. 1) is also tapejarid.
? Chaoyangopteridae
Apatorhamphus. A fragment of an edentulous rostrum missing its anterior tip (FSAC-
KK 5010) collected at Aferdou N’Chaft has been made the holotype of a third genus
and species of azhdarchoid, Apatorhamphus gyrostega, possibly a chaoyangopterid, from
the Kem Kem Group (McPhee et al. 2020). McPhee et al. assigned several additional
fragmentary rostra to A. gyrostega including FSAC-KK 5011, 5012 and 5013, BSP
1993 IX 338, originally identied as pteranodontid (Wellnhofer and Buetaut 1999;
Fig. 96A-E) and more recently as azhdarchid (Averianov et al. 2008, Ibrahim et al.
2010, Averianov 2014), and CMN 50895, originally determined by Rodrigues et al.
(2011, g1) as possibly a fragment of the mandibular symphysis of a dsungaripteroid.
An additional specimen, FSAC-KK 5013, identied as a fragment of the mandibular
symphysis, is almost perfectly complimentary to the holotype and tentatively assigned
by McPhee et al. to this new taxon. Further jaw fragments including FSA-KK 27 (Fig.
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
122
96F-J), FSAC-KK 29 (Fig 100A-E), FSAC-KK 32 (Fig 100F-H) and UCRC PV161
(Fig. 100I-K) collected in 1995 near Taouz, likely also pertain to this pterosaur.
e rostrum shows a relatively rapid increase in depth posteriorly and has a slightly
concave dorsal prole, which is typical of chaoyangopterids, but not other azhdar-
choids. e lateral and palatal surfaces bear prominent foramina and the palatal surface
has well developed dental margins, but no median ridge. Posteriorly the bone walls of
the rostrum are remarkably thin, but toward the tip they become much more robust
enclosing a deep but increasingly narrow central lumen. Unlike azhdarchids, the jaws
of which have a ‘Y’ shaped cross-section (Wellnhofer and Buetaut 1999, g. 4a; Ibra-
him et al. 2010: g. 2c, d), the jaws of this pterosaur have a rounded, sub-triangular
cross-section (e.g., Fig. 100C, D, H, K). FSAC-KK 5010 is 211 mm long. Compari-
son with more complete remains of chaoyangopterids (e.g., Lü et al. 2008) suggests
that the prenarial rostrum of this individual was at least 0.3 m in length, the skull at
least 0.6 m long and the wingspan in the region of 3–4 m, or more.
A combination of features including the shape of the rostrum, its unusual cross-
sectional prole and the shape and distribution of foramina appear to distinguish
FSAC-KK 5010 from other edentulous taxa found in the Kem Kem group, and azh-
darchoids more generally although, in the latter case, comparison is often hampered
by severe compression of the skull remains, for example in taxa from the Crato and
Jiufotang Formations. While FSAC-KK 5010 compares more closely to the rostrum
of chaoyangopterids than to other azhdarchoids, the possibility that it might, for ex-
ample, be thalassodromeid cannot be entirely excluded, hence the caution in assigning
this new species to Chaoyangopteridae.
Figure 101. Azhdarchid pterosaur rostral fragment from the Kem Kem Group. FSAC-KK 28 in (A)
lateral, (B) ?dorsal, (C) ?ventral and (D) posterior view. Scale bar equals 3 cm.
Kem Kem Group of Morocco 123
Figure 102. Near complete ?third cervical of an azhdarchid pterosaur from the Kem Kem Group. FSAC-
KK 3088 in (A) ventral, (B) dorsal, (C) right lateral, (D) left lateral, (E) anterior and (F) posterior view.
Scale bar equals 5 cm.
Azhdarchidae Nessov, 1984
Alanqa. Alanqa saharica, Ibrahim et al. 2010, was founded on a partial mandibular
symphysis (FSAC-KK 26; Fig. 98), reinterpreted here as a rostrum, collected in situ in
2008 at Aferdou N’Chaft (Ibrahim et al. 2010). Other Kem Kem group remains that
can be assigned to this taxon include BSP 1996 I 36 (Wellnhofer and Buetaut 1999:
g. 4), CMN 50859 (Rodrigues et al. 2011: g. 1), FSAC-KK 4000 (Martill and Ibra-
him 2015, g. 3), a specimen from a private collection (Martill and Ibrahim 2015: g.
5) and FSAC-KK 28 (Fig. 101).
Fragments of the rostrum and mandibular symphysis of this pterosaur have been
described in detail, and gured by Wellnhofer and Buetaut (1999), Ibrahim et al.
(2010), and Martill and Ibrahim (2015). Alanqa saharica is characterized by remark-
ably straight jaw margins and a pronounced boss on the palatal surface of the ros-
trum, which is matched by paired accessory facets on the occlusal surface of the
mandibular symphysis (Martill and Ibrahim 2015: g. 4f). e latter features have
not been reported in any other pterosaur, with the exception of Xericeps curvirostris
Martill et al. 2018, suggesting a close relationship between these taxa. e holotype,
FSAC-KK 26, appears to belong to an individual with an estimated wingspan of 3–4
m (Ibrahim et al. 2010).
e only phylogenetic analysis to include Alanqa to date (Longrich et al. 2018)
recovered this pterosaur as a thallassodromeid. However, this was based on the assump-
tion that the holotype represented the mandibular symphysis, rather than the rostrum,
as proposed here. ree features: highly elongate slender jaws with remarkably straight
margins and an unusual ’Y’ shaped cross-section, as found for example in Quetzalcoatlus
Nizar Ibrahim et al. / ZooKeys 928: 1–216 (2020)
124
(Kellner and Langston 1996: g. 7), suggest that Alanqa and its close relative, Xericeps,
are members of Azhdarchidae.
Xericeps. Xericeps curvirostris Martill et al. 2018, is represented by a single frag-
ment of a mandibular symphysis (FSAC-KK 10700) commercially collected from the
Douira Formation at Aferdou N’Chaft (Fig. 99). e holotype, described in detail by
Martill et al. 2018, is distinguished by its curvature in lateral view, with markedly con-
cave dorsal and convex ventral margins. Unique to this pterosaur there is a pronounced
midline groove on the ventral border of the mandibular symphysis. Comparison with
more complete remains of azhdarchoids suggests that FSAC-KK 10700 was a large
individual of at least 3–4 m in wingspan.
Among azhdarchoids the long slender mandibular symphysis of Xericeps curvirostris
(Fig. 99) is most closely comparable to that of azhdarchids such as Quetzalcoatlus (Kell-
ner and Langston 1996) and Alanqa (Ibrahim et al. 2010). Indeed, Alanqa saharica and
Xericeps curvirostris share a seemingly unique feature: well developed paired accessory oc-
clusal surfaces on the posterior portion of the dorsal surface of the mandibular symphysis
(Martill and Ibrahim 2015, Martill et al. 2018). ese similarities, and the co-occurence
of the remains in the same deposit, raise the possibility that A. saharica and X. curvirostris
(Table 8) might be synonymous. Jaw morphology can be quite variable in pterosaurs, as a
result of ontogeny, sexual dimorphism (reected in the presence or absence of crests) and
natural variation (Averianov 2014). Moreover, the morphological variation subtended
by FSAC-KK 26 and FSAC-KK 10700 falls within the range of variation exhibited by,
for example, the jaws of Rhamphorhynchus (Bennett 1995). However, additional, more
complete remains are needed to demonstrate, or discount, synonymy.
Azhdarchidae indet.
e Kem Kem Group has yielded several well-preserved cervical vertebrae comparable
to those described for azhdarchids such as Quetzalcoatlus (Howse 1986), Phosphatodra-
co (Pereda-Suberbiola et al. 2003) and Cryodrakon (Hone et al. 2019). ese include
two highly elongate vertebrae (Kellner and Mader 1996, Rodrigues et al. 2011), likely
the fourth or fth in the cervical series, and a fragment of a much larger cervical repre-
senting an individual of at least 6 m in wingspan (Ibrahim et al. 2010: g. 6). A second
individual of comparable size is represented by a nearly complete cervical vertebra
(FSAC-KK 3088; Fig. 102). is relatively short vertebra, approximately three times
longer than wide, is most closely comparable in its proportions to the third cervical of
Phosphatodraco (Pereda-Suberbiola et al. 2003). Additional azhdarchid vertebrae, some
of very large size, have yet to be described.
Azhdarchoidea indet. Numerous limb bones including the humerus, ulna, wing-
metacarpal, wing-phalanges, femur and tibia have been collected in recent years. So far,
however, only a single humerus has been described (Rodrigues et al. 2011). e humerus
was assigned by these authors to the Azhdarchoidea of which four species (a tapejarid, a
? chaoyangopterid and two azhdarchids) have now been described from the Kem Kem
group. It is not clear, at present, to which if any of these taxa the humerus may belong.
e same will likely apply to the many, as yet undescribed, limb bones of azhdarchoids.
Kem Kem Group of Morocco 125
Dinosauria Owen, 1842
Dinosaurs are represented by theropods and sauropods, as well as fragmentary remains
of uncertain anities, including a large ornithischian footprint (Kellner and Mader
1997, Novas et al. 2005a, Cavin et al. 2010, Ibrahim et al. 2016). eropods are rep-
resented by abelisaurids (Russell 1996, Mahler 2005, Zitouni et al. 2019), spinosaurids
(Buetaut 1989, 1992, Russell 1996, Milner 2003, Dal Sasso et al. 2005, Ibrahim et al.
2014b), carcharodontosaurids (Russell 1996, Sereno et al. 1996), and the enigmatic Del-
tadromeus (Sereno et al. 1996). Sauropods include a rebbachisaurid (Lavocat 1954, Rus-
sell 1996, Wilson and Allain 2015) and a titanosaur (Russell 1996, Ibrahim et al. 2016).
Isolated and often fragmentary dinosaur bones and teeth are found in all major
localities in both formations in the Kem Kem Group. Skull bones are rare and usu-
ally consist of jaw fragments, pieces of braincase, or the quadrate condyles. On rare
occasions, partial skulls and associated and even articulated skeletons are preserved
(Lavocat 1954, Sereno et al. 1996, Ibrahim et al. 2014b, Wilson and Allain 2015). e
bones, teeth, and footprints of theropods are more common than those pertaining to
sauropods and especially ornithischians.
Ornithischia Seeley, 1888
Ornithischian teeth and footprints are extremely rare in the Kem Kem Group; orni-
thischian cranial or postcranial bones have yet to be identied. Evidence from a single
small isolated crown (Fig. 103) and a single large footprint (Sereno et al. 1996) indicate
that small- and large-bodied ornithischians were at least transiently present.
A small partial subtriangular crown was recovered from Oum Tkout in the Douira
Formation from a small-bodied ornithischian (Fig. 103). Both sides of the crown have
similar enamel thickness and a broadly rounded primary ridge, which is slightly more
prominent on the presumed labial side (Fig. 103A). ere are no secondary ridges,
enamel texture or wear facets. e denticles, which number six to each side of the
large apical denticle, decrease in size toward the base of the crown, curve away from
the crown midline, and terminate in blunt rounded tips. e axes of the denticles
are angled ca. 45° to the crown axis. Near the fracture surface on the labial side (Fig.
103A), the enamel appears to curve away from the crown base,