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Abstract

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
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... The 'Kem Kem Compound Assemblage' (KKCA) along the Algerian-Moroccan border is a series of fossiliferous localities, Cenomanian in age, particularly rich in terrestrial and marine vertebrates (Russell 1996;Sereno et al. 1996;Russell and Paesler 2003;Cavin et al. 2010;Läng et al. 2013;Ibrahim et al. 2017Ibrahim et al. , 2020. Most of the taxa discovered in the KKCA are represented by fragmentary and disarticulated elements -in some cases only single or fragmented bones -with the exception of only a very few articulated skeletons (see review in Ibrahim et al. 2020). ...
... The 'Kem Kem Compound Assemblage' (KKCA) along the Algerian-Moroccan border is a series of fossiliferous localities, Cenomanian in age, particularly rich in terrestrial and marine vertebrates (Russell 1996;Sereno et al. 1996;Russell and Paesler 2003;Cavin et al. 2010;Läng et al. 2013;Ibrahim et al. 2017Ibrahim et al. , 2020. Most of the taxa discovered in the KKCA are represented by fragmentary and disarticulated elements -in some cases only single or fragmented bones -with the exception of only a very few articulated skeletons (see review in Ibrahim et al. 2020). The theropod dinosaurs from the KKCA are mostly referred to the clades Abelisauridae, Carcharodontosauridae and Spinosauridae (Russell 1996;Sereno et al. 1996;Chiarenza and Cau 2016;Ibrahim et al. 2020). ...
... Most of the taxa discovered in the KKCA are represented by fragmentary and disarticulated elements -in some cases only single or fragmented bones -with the exception of only a very few articulated skeletons (see review in Ibrahim et al. 2020). The theropod dinosaurs from the KKCA are mostly referred to the clades Abelisauridae, Carcharodontosauridae and Spinosauridae (Russell 1996;Sereno et al. 1996;Chiarenza and Cau 2016;Ibrahim et al. 2020). Carcharodontosauridae includes medium-to giant-sized species, with a fossil record spanning from the Upper Jurassic to the lower Upper Cretaceous of Africa, Asia, Europe, North America and South America (Stromer 1931;Rauhut 1995Rauhut , 2011Sereno et al. 1996;Coria and Currie 2006;Brusatte and Sereno 2007;Sereno and Brusatte 2008;Brusatte et al. 2010;Carrano et al. 2012;Coria et al. 2020;Meso et al. 2021;Canale et al. 2022). ...
Article
The ‘Kem Kem Compound Assemblage’ (KKCA) along the Algerian-Moroccan border is a series of fossiliferous localities, Cenomanian in age, particularly rich in large-bodied theropod dinosaurs. Two species of carcharodontosaurid allosauroids have been identified in these units, Carcharodontosaurus saharicus and Sauroniops pachytholus. Recently, the validity of the second species has been challenged, and all carcharodontosaurid material from the KKCA has been referred uniquely to the former species. Here, we describe a new theropod cranial material from the KKCA which is referred to Carcharodontosauridae, including one partial maxilla which shows a morphology distinct from that of C. saharicus. We review the arguments used to interpret Sauroniops holotype as an immature individual of Carcharodontosaurus and show that they were based on non-homologous comparisons and on the misinterpretation of the original description of S. pachytholus: The latter is confirmed to be a valid taxon, distinct from C. saharicus and with an inferred body size comparable to the largest carcharodontosaurids. The presence of more than one giant carcharodontosaurid species in the Cenomanian of Morocco recalls the carcharodontosaurid diversity from penecontemporary units from Argentina.
... Unknown fossil site near the southern border of Er Rachida Province, Morocco. Kem Kem Group; late Albian-early Cenomanian (see Ibrahim et al. 2020 for further details). ...
... Therefore, the genus Elosuchus currently includes two species: E. cherifiensis and E. broinae. Ibrahim et al. (2020) noted that they only differ in minor anatomical characters, but none of them pertaining to the morphology of the premaxilla (Young et al. 2016). As a result, the attribution of IPS3303 to a lower rank than the genus level is impossible here. ...
... All of them show a similar conical-shaped crown with apical ornamented enamel consisting of anastomosing ridges, but the premaxillary tooth does not have carinae as the maxillary ones, it is less curved vocally, and the anastomosing texture covers more surface of the tooth crown (Figure 3). Similar morphology differences are recognised along the jaw in extant crocodiles, putative semiaquatic dinosaurs (Ibrahim et al. 2020), and mosasaurs (Street et al. 2021). In fact, it is noteworthy that the false denticulations and anastomosing enamel texture are produced by the same amelogenesis process (Sander 1999(Sander , 2000 in which the underlying dentine does not contribute to the relieve development, but as a differential thickening of the enamel-, and because of that it is not surprising to find them coexisting in the same tooth. ...
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Sometimes Natural History Museums unknowingly treasure singular specimens in their collections for decades. The re-discovery of such elements allows the description of previously unknown features of well-known taxa. Here, we describe a nearly complete left premaxilla attributed to the pholidosaurid Elosuchus. Specimen IPS3303 shows some remarkable differences with previously known premaxillae of Elosuchus, especially concerning the relative position of the fifth premaxillary tooth and the premaxilla-maxilla sutural surface morphology. Because of the scarcity of current data, it is difficult to evaluate the significance of such differences. The described element is about 40% larger than the largest premaxilla of Elosuchus known so far, suggesting that this taxon could achieve remarkable body size proportions. The preliminary analyses of the dentition and the neurovascular system of the premaxilla provide new insight into the palaeoecology of this riverine crocodylomorph from the Cretaceous of Africa.
... That skull was subsequently included in a list of specimens attributable to Galianemys whitei by Gaffney et al. (2006), a taxon defined in Gaffney et al. (2002), after the work of Lapparent de Broin and Werner (1998). It was also figured in a more recent publication (see figure 73A-D in Ibrahim et al., 2020 but only through photographs). Therefore, no detailed illustration showing the limits of the bones that make up that skull is currently available, and neither is a detailed description of it. ...
... In addition, each bone of the specimen MNHN.F MRS 2098 was individually reconstructed, and they were figured, in articulation, using a different color for each of them ( Figures 5-7). The linear and angular measurements of the cavum cranii, carotid canals and of the labyrinths were obtained following the protocols previously established in the literature (see supplementary information in Ibrahim et al., 2020; and references therein). ...
... Locality and horizon: Hammada du Guir, eastern Erfoud, Errachidia Province, eastern central Morocco. Kem Kem Group, Cenomanian (see Ibrahim et al., 2020; and references therein). Osteological description: MNHN.F MRS 3105 corresponds to a triangular skull in dorsal view (Figures 2a,b and 8a). ...
Article
Galianemys is one of the three genera of Cearachelyini (Pleurodira, Bothremydidae) so far defined, being the only one identified in Africa (in the Cenomanian of Morocco). It is represented by two species, Galianemys whitei and Galianemys emringeri, both being identified by several skulls. The other two representatives of Cearachelyini are both South‐American forms, and only the species Cearachelys placidoi (from the Albian of Brazil) preserves cranial remains, including a partial skull corresponding to its holotype. However, despite the relatively great number of skulls identified for both Galianemys spp. and Cearachelys placidoi, information about the neuroanatomy of this lineage is very limited. The three‐dimensional (3D) reconstruction of the skulls of two specimens belonging to the genus Galianemys, each of them representing a different species, is performed here for the first time. All of the cranial bones of one of them are also virtually reconstructed to accurately characterize them. In addition, the 3D models of the main neuroanatomical structures (i.e., cranial, nasal, and labyrinthic cavities, and nervous and carotid canals) of both specimens were generated, most of them being described in detail for first time in Cearachelyini. Neuroanatomical differences are recognized when the skulls of both species of Galianemys analyzed here are compared. In addition, the comparison between the neuroanatomy of Galianemys spp. and that of other non‐Cearachelyini bothremydids allow us to identify some differences between those lineages, but also recognize other shared characters for the entire lineage of Bothremydidae, to providing a more precise characterization within Pleurodira.
... Jeddaherdan aleadonta, widely accepted as a mid-Cretaceous acrodontan since its original description (e.g. Ibrahim et al., 2020;Evans, 2022;Ijouiher, 2022), has been considered in various studies as a key taxon critical for understanding the origin and evolutionary history of iguanian lizards, with important implications for both palaeobiogeographic reconstructions (Simões et al., 2017;Bittencourt et al., 2020;Rage and Gheerbrant, 2020) and node calibrations (Lafuma et al., 2021;Marjanovi c, 2021;Paparella, 2021;although Marjanovi c (2021) cautiously "preferred not to use Jeddaherdan to date the origin of Iguania as long as further material has not been discovered"). However, our study shows that the holotype and only known specimen of J. aleadonta is a dentary fragment of a recent (or subfossil) subadult of Uromastyx sp., which is a common lizard in the Kem Kem area today (represented by the species U. nigriventris; Wilms et al., 2009;Tamar et al., 2018). ...
Article
Jeddaherdan aleadonta Apesteguía et al., 2016 is currently known as the first and single Mesozoic iguanian lizard from Africa. The original description and age of the holotype and only known specimen (i.e. a dentary fragment bearing five teeth) are revised here. We show that this fragmentary specimen was misinterpreted anatomically, does not come from Cretaceous beds but is instead Quaternary in age, and must be assigned to an indeterminate species of Uromastyx (spiny-tailed lizards). Therefore, the genus Jeddaherdan is considered a junior synonym of Uromastyx, and the species J. aleadonta (= Uromastyx sp.) is considered a nomen dubium. Our results refute the presence of iguanian lizards in the Mesozoic of Africa and have major implications for reconstructing the evolution and palaeobiogeography of this group.
... The palaeogeographic position of the peri-Adriatic region close to the northern Gondwana margin suggests a comparison between the Molfetta specimens and those known from Northern Africa. Several theropod tracks were reported from Upper Jurassic to Upper Cretaceous deposits of Morocco (Boutakiout et al., 2009(Boutakiout et al., , 2018Belvedere et al., 2010Belvedere et al., , 2013Belvedere et al., , 2019Nouri et al., 2011;Masrour et al., 2013;Ibrahim et al., 2014Ibrahim et al., , 2020 and Algeria (Bensalah et al., 2005;Mahboubi et al., 2007;Bessedik et al., 2008;Chabou et al., 2015;Mammeri, 2018). Several dinosaur tracks are known from the Iouarid ene Fm. (Central High Atlas, Morocco), dated ?Oxfordian-Kimmeridgian. Boutakiout et al. (2009) and Belvedere et al. (2010) described giant theropod footprints (FL > 50 cm; type specimen: 23IGR1.7; ...
Article
The lower Albian track-bearing surface of the San Leonardo quarry (Molfetta, Apulia) is characterised by more than 800 footprints, produced by both quadrupedal and bipedal dinosaurs. Six well-preserved bipedal trackways, composed of tridactyl footprints are attributed to medium-to large-sized theropod dinosaurs. Only one clear but poorly preserved trackway and numerous isolated manus-pes couples have been attributed to quadrupedal dinosaurs. The tridactyl ichnoassemblage, analysed using both traditional methods and close-range photogrammetry, is represented by weakly mesaxonic and robust specimens. Morphological comparison with Upper Jurassic and Lower Cretaceous theropod tracks from surrounding areas, supported by morphometric analyses, points out a highest affinity with the specimens from Switzerland and North Africa. Nevertheless, a set of unique characters appears to justify the establishment of a new ichnospecies, Jurabrontes melphicticus. Additionally, the photogrammetric models of the quadrupedal trackway and four isolated manus-pes sets suggest they belong to the same morphotype, represented by asymmetrical tetradactyl pes and highly digitigrade tetra- or pentadactyl manus. These tracks share numerous morphological characters with both the ichnogenera Tetrapodosaurus and Metatetrapodus and thus can be attributed to a medium-sized ankylosaurian trackmaker.
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The Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan has yielded many isolated bones and teeth representing a variety of non-avian theropod dinosaurs. A pedal phalanx II-2 indicates the presence of a dromaeosaurid theropod that attained a larger body size than any previously known member of that clade. The same formation also yielded a large maxillary fragment that has recently been described as a neovenatorid carcharodontosaurian ( Ulughbegsaurus uzbekistanensis ). However, this specimen lacks unambiguously diagnostic features of that clade, and its purported carcharodontosaurian characters are either taphonomic artefacts or also shared by dromaeosaurids. Thus, the phylogenetic relationships of Uleghbegsaurus uzbekistanensis remain uncertain. A giant dromaeosaurid occurred together with the medium-sized tyrannosauroid Timurlengia euotica in the Bissekty assemblage.
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A new pterosaur, Afrotapejara zouhri gen. et sp. is described on the basis of a partial rostral fragment from the Cretaceous Kem Kem beds of Takmout, near Erfoud in southern Morocco. The taxon is distinguished from all other Tapejaridae on the possession of a dorsal expansion of the rostral margin a short distance from the rostral tip. Tapejarid features include a downturned rostrum (autapomorphic), edentuly, expansion of the rostral median crest (autapomorphic) and the presence of small foramina on the lateral margins and occlusal surface. The new specimen is the fourth edentulous pterosaur taxon from the Kem Kem beds and is the first unambiguous occurrence of Tapejaridae in Africa.
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Isolated cervical vertebrae from the mid Cretaceous Kem Kem beds of south east Morocco are referred to the theropod dinosaur clade Abelisauroidea, and represent the first axial remains from this deposit referred to this group. An isolated axis is referred to Abelisauroidea on account of the invaginated spinopostzygapophyseal lamina; the extremely large, projecting and pointed epipophyses; and the anteroposteriorly long, transversely compressed neural spine with a gently convex and unexpanded dorsal margin. In addition, postzygapophyseal facets which completely overhang the centrum posteriorly and lack lateral orientation indicate abelisaurid affinities. An anterior cervical (C4?) is referred to Noasauridae based on an anteriorly-positioned, reduced neural spine and extremely well developed centroprezygapophyseal fossae. This specimen represents both the smallest dinosaur and the first definitive small-bodied dinosaur from the Kem Kem beds. The affinities of the new material are discussed in the context of other abelisauroid remains reported from the Kem Kem assemblage and elsewhere in Africa.
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Azhdarchid pterosaurs have been known since 1972 from upper Campanian deposits of Alberta, Canada. Originally represented by only very fragmentary remains tentatively assigned to the genus Quetzalcoatlus, additional material uncovered over the years has revealed that the taxonomic identity of the Alberta pterosaur material is at odds with this in the light of the growing understanding of azhdarchid diversity. Here, we describe previously undocumented pterosaur remains from Alberta and reassess previously studied material. The specimens collected from the Dinosaur Park Formation can be assigned to a new genus and species Cryodrakon boreas, gen. et sp. nov. The largest elements referable to this taxon suggest that this genus reached sizes comparable to those of other giant azhdarchids.
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Two specimens of a new species of horseshoe crab, Mesolimulus tafraoutensis sp. nov., are described from the Late Cretaceous (Cenomanian–Turonian) Gara Sbaa Lagerstätte of southeast Morocco. These most likely represent juveniles, as suggested by their small size and possession of a number of characteristics, such as short genal spines, that are characteristic of modern juvenile horseshoe crabs. Despite this, the development of the prosomal keel into a broader cardiac ridge and the scalloped lateral margins of the cardiac lobe clearly place these specimens within Mesolimulus. A further characteristic, the occurrence of only two tubercles on the thoracetron pleural ridges, marks Mesolimulus tafraoutensis sp. nov. as a distinct species. As Mesolimulus resolves phylogenetically as a total group limulid outside of the crown group, the new discovery indicates that stem-lineage limulids persisted into the Cretaceous and co-existed with crown-limulids as they underwent their major radiation.