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Palaeontologia Electronica
palaeo-electronica.org
http://zoobank.org/89E8C946-70F3-4C4F-A591-770649B4126D
Rauhut, Oliver W.M., Hübner, Tom R., and Lanser, Klaus-Peter. 2016. A new megalosaurid theropod dinosaur from the late Middle
Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic. Palaeontologia
Electronica 19.2.26A: 1-65
palaeo-electronica.org/content/2016/1536-german-jurassic-megalosaurid
Copyright: Palaeontological Association August 2016
A new megalosaurid theropod dinosaur from
the late Middle Jurassic (Callovian) of north-western Germany:
Implications for theropod evolution and faunal turnover
in the Jurassic
Oliver W.M. Rauhut, Tom R. Hübner, and Klaus-Peter Lanser
ABSTRACT
Fragmentary remains of a large, robustly built theropod dinosaur were recovered
from the marine middle Callovian Ornatenton Formation of north-eastern Northrhine-
Westphalia, Germany. The specimen includes a premaxilla, maxilla, lacrimal, postor-
bital, dentary, several caudal vertebrae, ribs, fibulae, astragalus, and partial calca-
neum. It is here described as a new species of megalosauroid, Wiehenvenator albati n.
gen. n. sp., diagnosed by a strongly reduced maxillary antorbital fossa on the base of
the ascending process of the maxilla, a very short anterior ramus of the lacrimal with
an additional pneumatic depression anteroventral to the lacrimal fenestra, a trans-
versely expanded orbital facet in the postorbital, and a laterally flexed proximal end of
the ascending process of the astragalus. Phylogenetic analysis recovers Wiehenvena-
tor as a megalosaurine megalosaurid, sister taxon to the Late Jurassic genus To rvo-
saurus. It thus adds to the considerable diversity of megalosauroids in the Middle
Jurassic. A time-calibrated phylogeny of theropods indicates a rapid radiation of
averostran theropods between the Toarcian and the Bathonian. This radiation was
probably triggered by the Pliensbachian-Toarcian extinction event, which might have
been more important for theropod evolution than the Triassic-Jurassic extinction. The
fossil record indicates a faunal turnover from megalosauroid dominated Middle Juras-
sic to allosauroid / coelurosaur dominated Late Jurassic faunas. However, differences
in the Middle and Late Jurassic theropod fossil records both in respect to geographic
distribution of localities, as well as sampled environments make this inference prob-
lematic, at least in respect to allosauroids. An analysis of environmental preferences of
allosauroids and megalosauroids indicates that the former preferred inland environ-
ments, whereas the latter are more common in nearshore environments.
Oliver W.M. Rauhut. Staatliche naturwissenschaftliche Sammlungen Bayerns (SNSB), Bayerische
Staatssammlung für Paläontologie und Geologie, Department for Earth and Environmental Sciences and
GeoBioCenter, Ludwig-Maximilians-University, Richard-Wagner-Str. 10, D-80333 München, Germany.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
2
o.rauhut@lrz.uni-muenchen.de
Tom R. Hübner. Posener Str. 10, 30659 Hannover, Germany. Current address: paläon - Forschungs- und
Erlebniszentrum Schöninger Speere, Paläon 1, 38364 Schöningen, Germany. Tom-Ray@gmx.net
Klaus-Peter Lanser. Landesverband Westfalen-Lippe (LWL), Museum für Naturkunde, Sentruper Str. 285,
D-48161 Münster, Germany. Current address: Langebusch 948159 Münster, Germany.
klaus.peter.lanser@gmx.de
Keywords: Megalosauroidea; Ornatenton Formation; theropod evolution; Jurassic
Submission: 3 March 2016 Acceptance: 27 June 2016
INTRODUCTION
The first dinosaur to be described scientifically
was a Middle Jurassic theropod from Europe,
Megalosaurus, from the Bathonian of England
(Buckland, 1824), although the species name, M.
bucklandii Mantell, 1827, was not coined until three
years later (Mantell, 1827). The taxon was based
on an assortment of bones from the Taynton Lime-
stone Formation of Stonesfield, Oxfordshire, of
which an isolated dentary was recently selected as
lectotype (Benson et al., 2008). As this was the first
theropod dinosaur known, almost all theropod
remains found in subsequent decades were
referred to the genus Megalosaurus, and so this
genus became a wastebasket taxon for theropod
taxa ranging from the Late Triassic to the latest
Cretaceous (see Benson et al., 2008; Benson,
2010a; Carrano et al., 2012). Even though a revi-
sion of this situation and a restriction of the name
Megalosaurus to certain taxa from the Jurassic of
Europe started with the work of von Huene (1923,
1926), it remained common practice to refer iso-
lated remains to this genus until late in the 20th
century (e.g., del Corro, 1974), and the family Meg-
alosauridae long remained the receptacle for thero-
pod taxa that could not readily be placed in one of
the more derived families (e.g., Tyrannosauridae,
Ornithomimidae). Following the growing recogni-
tion that Megalosaurus was a problematic taxon
(e.g., Molnar et al., 1990; Allain and Chure, 2002;
Day and Barrett, 2004) and that there were two dis-
tinct clades that can be distinguished at the base of
Tetanurae and outside Coelurosauria (e.g., Sereno
et al., 1994, 1998; Sereno, 1999; Allain, 2002;
Rauhut, 2003), the name Megalosauridae became
less frequently used in recent decades (Holtz et al.,
2004). However, it was not until the recent work of
Benson (2008, 2009, 2010a, 2010b; Benson et al.,
2008) that the taxonomic status of Megalosaurus
bucklandii and several of the referred materials
from the British Middle Jurassic have been finally
resolved, and Benson (2010a) and Carrano et al.
(2012) recently provided a phylogenetic framework
for the recognition of a monophyletic superfamily
Megalosauroidea, including a monophyletic Mega-
losauridae (with phylogenetic definitions for these
clades first having been proposed by Holtz et al.,
2004).
The Middle Jurassic of Europe has yielded the
highest diversity of theropod dinosaurs currently
known for this time, yet diagnostic remains have so
far only been described from England and France.
The recognition of a monophyletic Megalosauridae
and the phylogenetic work by Benson (2010a) and
Carrano et al. (2012) indicate that the majority (at
least seven out of 10) of these taxa can be referred
to this clade. Middle Jurassic species from Europe
that are currently regarded as valid include the
megalosaurids Megalosaurus bucklandii Mantell,
1827 (see Benson et al., 2008; Benson 2009,
2010a; Carrano et al., 2012), Poekilopleuron buck-
landii Eudes-Deslongchamps, 1837 (see Allain and
Chure, 2002), Magnosaurus nethercombensis (von
Huene, 1923) (see von Huene, 1926; Benson,
2010b), Eustreptospondylus oxoniensis Walker,
1964 (see von Huene, 1926, 1932; Sadleir et al.,
2008), Piveteausaurus divesensis (Walker, 1964)
(see Taquet and Welles, 1977), Dubreuillosaurus
valesdunensis (Allain, 2002) (see also Allain,
2005), and Duriavenator hesperis (Waldman,
1974) (see Benson, 2008), the Megalosauroidea
incertae sedis Streptospondylus altdorfensis von
Meyer, 1832 (see Allain, 2001), the Tetanurae
incertae sedis Cruxicheiros newmanorum Benson
and Radley, 2010, and the basal tyrannosauroid
Proceratosaurus bradleyi (Woodward, 1910) (see
Rauhut et al., 2010). Stratigraphically, these taxa
range from the Early Bajocian (Magnosaurus neth-
ercombensis) to the Late Callovian (Eustrepto-
spondylus, Piveteausaurus, Streptospondylus). As
most of Europe was covered by shallow seas in the
Middle Jurassic (Smith et al., 1994), all of the
remains from England and France come from
PALAEO-ELECTRONICA.ORG
3
marine deposits and thus obviously represent ani-
mals that inhabited the numerous smaller and
larger islands in the area that is now north-western
central Europe. As noted by Benson (2010a), there
might have been some regional endemism at least
during the Bathonian, as there are no taxa shared
between deposits of that time in England and
France.
In 1998, Friedrich Albat, a geologist prospect-
ing for the LWL (Landschaftsverband Westfalen-
Lippe) Museum of Natural History in Münster, dis-
covered remains of a large theropod dinosaur in an
abandoned quarry within the Ornatenton Forma-
tion (Callovian) at Lutternsche Egge, in the Wie-
hengebirge near the city of Minden (Figure 1).
Subsequent excavation at the site by the LWL Nat-
FIGURE 1. Geographic and stratigraphic position of the locality where the new theropod was found. 1, Overview map
of Germany, indicating the area of the locality of the new theropod in north-eastern Northrhine-Westphalia. 2, locality
of the disused Pott quarry at Lutternsche Egge in the Wiehengebirge. 3, Simplified stratigraphic column of the rocks
that crop out in the Wiehengebirge (E = east; W = west). Modified from Riegraf (1994). 4, Geological map of the area
between Bünde and Minden. Middle Jurassic units, including the Ornatenton, are represented by the dullish dark
green that follows the course of the Wiehengebirge; light blue-grey colours represent Upper Jurassic units; light
green marks the Lower Cretaceous (‘Wealden’) outcrops; orange colours represent Upper Triassic rocks. From the
Northrhine-Westphalian Geological Survey (www.gd.nrw.de).
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
4
ural History Museum from 1998 to 2001 resulted in
the recovery of a fragmentary theropod skeleton,
together with abundant marine invertebrates and
fossil wood. This specimen, which represents the
first diagnostic dinosaur remain from the Middle
Jurassic of Germany, is described here.
GEOLOGICAL AND PALAEONTOLOGICAL
CONTEXT
The Wiehengebirge is a chain of hills up to
320 m high with a NW-SE orientation, which
belongs to the northernmost ranges of the central
German mountain range at the southern rim of the
northern German plain. Together with the Teuto-
burg forest further to the south, it forms a hilly
wedge that extends far into the plains. The Wie-
hengebirge extends from the city of Bramsche in
Lower Saxony in the west to the city of Porta West-
falica in Northrhine-Westphalia in the east, where
the Weser river cuts through the range. East of the
Weser, the range continues under the name
Wesergebirge (Figure 1). The Wiehengebirge con-
sists of sediments of Middle and Late Jurassic age,
which crop out along the heights of the range,
closely following its course. They dip at 35° to 40°
towards the north-east and are overlain by Lower
Cretaceous sediments in the north. The Lower
Jurassic crops out in the plains south of the hills.
In the area of the Weser- and Wiehengebirge,
the sediments of the Upper Jurassic consist mainly
of hard sandstones and quartzites of Oxfordian
and Kimmeridgian age, which were formerly quar-
ried in numerous, now disused quarries. The
quarry operations thus exposed the underlying
Callovian Ornatenton. According to Mönnig (1993),
these layers represent the Eremnoceras corona-
tum biozone of the upper Middle Callovian and the
upper siltstone series of the Ornatenton Formation.
Thus, these sediments are of similar age to the
lower Oxford Clay, such as the Peterborough
Member of the Oxford Clay Formation in England.
The soft, rapidly eroding sediments dip at an angle
of 35° to 40° towards the NE, which leads to fre-
quent slumpings over large areas. Thus, the con-
stantly changing outcrop situation makes repeated
prospecting of these abandoned quarries neces-
sary. Over the years, these outcrops have mainly
yielded a rich invertebrate fauna, which was
described by Lange (1973) and Klassen (1984),
among others.
Since 1996, the LWL Museum of Natural His-
tory, which is in charge of the palaeontological pat-
rimony within the Landschaftsverband Westfalen-
Lippe, has carried out intensive prospection cam-
paigns in the area of the Wesergebirge and Wie-
hengebirge. These were triggered by the
information about vertebrate remains having been
discovered and excavated by private collectors,
especially in the Störmer quarry at Wallücke, a few
kilometres east of Bergkirchen. These remains dis-
covered by private collectors were subsequently
largely described by Michelis et al. (1996). In
preparation of this publication, the majority of these
specimens, especially the remains of Leedsichthys
problematicum, were transferred from several pri-
vate collections to the LWL Museum of Natural His-
tory. The remains described by Michelis et al.
(1996) as fragments of the stegosaurian dinosaur
Lexovisaurus were also later identified as belong-
ing to Leedsichthys problematicum (Liston, 2010).
The first step in the prospection for vertebrate
occurrences was the registration of all outcrops in
the area of the Weser- and Wiehengebirge,
together with visits to and an evaluation of these
outcrops. This represented an actualization of an
existing catalogue of outcrops within the entire
area of Westfalen-Lippe. The surveillance of the
outcrops was transferred to young scientists who
acted as contractors of the LWL Museum of Natu-
ral History. This soon led to first discoveries. Thus,
Gregor Bishop, a PhD student at the University of
Hannover, found parts of a crocodylomorph skull in
the float underneath the outcropping sediments in
a quarry at the Wülpker Egge in the Wesergebirge
east of Minden. Additional cranial remains were
subsequently found in situ and were recovered
with technical support from the quarry owner.
These remains were identified as Steneosaurus
sp. This success led to the continuation of the
prospection in the following year, this time carried
out by Friedrich Albat from Münster. In October
1998, the latter found remains of a theropod
maxilla in the disused Pott quarry, at Lutternsche
Egge, a few kilometres west of Bergkirchen, within
the city limits of Minden (Figure 1). This triggered
an excavation by a team from the LWL Museum für
Naturkunde from October 1998 to October 2001.
The disused quarry is approximately 650 m
long, and the outcropping layers of the Ornatenton
Formation dip north-east at c. 40°. The upper edge
of the outcropping sediments form the crest of the
Wiehengebirge in this area. The Ornatenton For-
mation crops out over a height of 25 to 35 m from
this crest to the now forested rubble at the foot of
the column. The locality is placed directly below the
crest of the Wiehengebirge, a short distance below
the overlying, lower Oxfordian Heersumer Beds,
which were here preserved with a thickness of c.
PALAEO-ELECTRONICA.ORG
5
1.5 m. Until the beginning of winter in December
1998, several theropod skeletal elements were
exposed over some 4.5 m (Figures 2, 3). These
remains were associated with marine inverte-
brates, such as ammonites, belemnites, brachio-
pods, serpulids, and bivalves, especially the oyster
Gryphaea dilatata. Further notable were numerous
coalified wood remains, which occurred over the
entire outcropping surface of the Ornatenton For-
mation and reached several metres in length.
The vertebrate remains were found in concen-
trations of the oyster Gryphaea dilatata, which
occurs in large numbers in the contact layer
towards the overlying Heersumer Beds at the top
of the Ornatenton Formation. This layer thus rep-
resents a condensation horizon at the unconformity
between the Middle Callovian Upper Siltstone
Series of the Ornatenton Formation and the Lower
Oxfordian of the Heersumer Beds (Mönnig, 1993).
This condensation horizon at the top of the middle
FIGURE 2. Quarry map of the excavation at Lutternsche Egge, showing the position of the different elements of the
new taxon in situ. Numbers refer to the specimen numbers of the separate elements (see text). Scale is in 50 cm
increments.
FIGURE 3. Outline reconstruction of Wiehenvenator albati n. gen., n. sp., indicating recovered elements. Based on
the reconstruction of Torvosaurus by Scott Hartman; used with permission. Scale bar equals 1 m.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
6
member of the Ornatenton Formation (the Upper
Siltstone Series of Mönnig, 1993) is widely distrib-
uted in the Ornatenton Formation in northern Ger-
many and also present some kilometres to the
west in the Störmer quarry at Wallücke, where it is
also unconformably overlain by the Heersumer
Beds, so that the uppermost member of the
Ornatenton Formation is missing (Michelis et al.,
1996).
According to Mönnig (1993), the Upper Silt-
stone Series of the Ornatenton Formation was
deposited in a shallow marine environment with an
input of clastic sediments from the west, presum-
ably the Rhenian or London-Brabant Massif. This
predominant direction of sedimentation might indi-
cate that remains of terrestrial vertebrates could
also have been washed in from these areas. The
condensation horizon itself represents a gap in
sedimentation, most probably due to a marked rise
in sea level in the Middle Callovian (Mönnig, 1993).
The bones had largely weathered out of the
surrounding sediments at the time of their discov-
ery and are thus rather poorly preserved. Bones
and teeth showed numerous breaks and cracks, so
that an extraction at the site would have led to the
destruction of the specimens. They were thus
excavated in jackets, which were subsequently
prepared in the laboratories of the LWL Museum
für Naturkunde. Following the excavation of the
main bone concentration, the surroundings were
searched for further remains. Some weathered
bone remains were found in the rubble below the
excavation site. Furthermore, a broken theropod
vertebral centrum had been found by collectors
(family Bragado from Petershagen) some 10 years
earlier c. 10 m east of the excavation site in the
rubble and was donated to the LWL Museum für
Naturkunde. Thus, the Ornatenton Formation was
searched over 35 m both east and west of the
locality for further remains over its entire exposed
height from the Heersumer Beds to the rubble at
the foot of the outcrops. Some weathered vertebral
centra and teeth of Liopleurodon sp. were found.
Almost exactly one year after the original discov-
ery, in mid-October 1999, remains of a second
theropod were found some 28.5 m north-west of
the first locality. These remains had largely weath-
ered out of the sediment and floated a few metres
down the slope. However, a maxillary fragment
was subsequently found in situ above the bone
and tooth fragments in the float.
Only a few hundred metres away from these
finds, a honorary member of the LWL Museum für
Naturkunde found a skull and lower jaws of the
crocodylomorph Metriorhynchus sp. on October 3,
2014, in a largely overgrown quarry further to the
west. As with the theropod remains from the Pott
quarry, this skull occurred directly below the Heer-
sumer Beds. These discoveries in the Middle
Callovian beds over a rather short distance demon-
strate the potential of these sediments and indicate
that more material might be found in the future.
MATERIALS AND METHODS
Bone Histology
In order to establish the ontogenetic stage of
the holotype specimen of the new taxon, we sec-
tioned one of the fibulae for a histological analysis.
The thin sections were produced in the preparation
lab of the Geomuseum at the Westfälische Wil-
helms-Universität Münster. The left fibula (WMN
P27479) was transversely cut approximately at the
border between the distal and middle third of the
shaft, close to an already present break, using a
Woco 50 precision saw. The obtained slice was
hardened with two-component RECKLI injection
resin EP and mounted on a glass slide, using two-
component Körapox 439 resin. After a second
transverse cut close to the glass slide, the section
was ground down to a thickness of approximately
30 µm, because of its dark inherent color and
abundant diagenetic alterations obscuring many
parts of the tissue. A second transverse thin sec-
tion of approximately 60 µm was made from the
remaining slab for comparison. The thin sections
were examined and photographed using a Leitz
Laborlux 12 Pol polarization microscope and a
Zeiss Axio Cam ICC3 camera. The whole-section
photo was made on a light table using a Nikon D3
camera with a 105 mm Micro Nikkor lens.
Phylogenetic Analysis
To establish the phylogenetic position of the
new taxon, we coded it in a revised version of the
matrix of Carrano et al. (2012). Several character
definitions of the original list of Carrano et al.
(2012), especially of cranial characters, were
revised and taxa recoded correspondingly (see
Appendix 1). In addition, we added the basal tyran-
nosaur Guanlong to the matrix in order to improve
taxon and character sampling in coelurosaurs (Xu
et al., 2006). Character codings for this taxon are
based on Xu et al. (2006) and own observations on
the type specimen (IVPP V-14531) by OWMR. Fur-
thermore, one taxon was deleted from the matrix.
The deleted taxon is the Chinese theropod
Leshansaurus, as neither Carrano et al. (2012) nor
PALAEO-ELECTRONICA.ORG
7
we studied this taxon personally, and the published
description (Li et al., 2009) is in Chinese, so cod-
ings could only be based on the sparse illustra-
tions. Following Xing et al. (2013, 2014), the
Chinese taxon ‘Dilophosaurus’ sinensis is consid-
ered to be a junior synonym of Sinosaurus triassi-
cus, and thus the latter name is used in the matrix.
Although of considerable potential biogeographic
interest, we did not include the Kimmeridgian Por-
tuguese megalosaurid Torvosaurus gurneyi in the
matrix (Hendrickx and Mateus, 2014a). In respect
to this species, we accept its referral to the genus
Torvosaurus, as this was based on synapomor-
phies that are not present in any other megalosau-
roid, including the new taxon described here, such
as the presence of a laterodorsal ridge within the
anteroventral part of the antorbital fossa (Hen-
drickx and Mateus, 2014a), and it has thus been
subsumed in this genus in our analysis. The result-
ing matrix thus had 62 taxa scored for 351 charac-
ters. The matrix is published in Morphobank
(www.morphobank.org) under project 2368.
The matrix was analysed under equally
weighted parsimony in TNT (Goloboff et al., 2008a,
2008b), performing a heuristic tree search starting
from 1000 replicates of Wagner trees (with random
addition sequence of taxa), followed by TBR
branch swapping (saving 10 trees per replicate).
Bootstrap and Bremer support values were calcu-
lated in TNT, and the same program was used to
identify wildcard taxa and calculate strict and
reduced consensus trees. Character optimizations
and number of additional steps needed for alterna-
tive topologies were evaluated on the strict and
reduced consensus trees in Mesquite 3.04 (Maddi-
son and Maddison, 2015).
Analysis of Theropod Faunal Changes
Apart from looking at the taxonomic composi-
tion of Middle and Late Jurassic theropod faunas
(see below), we also looked at the theropod fossil
record for the two epochs to track changes in
theropod faunas. For that, we extracted data for
Middle and Late Jurassic theropod localities from
the Paleobiology Database (paleobiodb.org), which
was updated on the basis of the literature and own
data (see Appendix 2). Only localities yielding skel-
etal specimens were considered, as a referral of
tracks to distinct clades is only possible in excep-
tional cases. The dataset included a total of 100
localities for the Middle and 256 localities for the
Late Jurassic. Of these localities, a total of 52
localities yielded remains that are at least identifi-
able in the clades Ceratosauria, Megalosauroidea,
Allosauroidea, and Coelurosauria for the Middle
Jurassic; for the Late Jurassic, the number of local-
ities with identifiable remains is 152. Only these
localities were considered in the analyses.
In addition to the stratigraphic and geographic
data on theropod occurrences, we also tried to
report ecological data, at least in the rather rough
categories, whether the theropod-bearing locali-
ties occur within marine, marginal (coastal, tidal),
or fully terrestrial geological units. This data was
partially taken from the Paleobiology Database,
and confirmed with the help of the primary litera-
ture in many cases. For the analysis of environ-
mental preferences, we only distinguished two
rough categories, inland terrestrial and ‘nearshore‘
(coastal/tidal/marine) environments, as theropods
are generally terrestrial animals, and occurrences
in marine environments thus reflect transport of ter-
restrial animals (which presumably mainly lived
close to the coast or on islands) into such deposits.
We then calculated the expected number of repre-
sentatives of the clades mentioned above for each
environment, using the formula
NexpA = (OX * EnvA)/EnvT
with NexpA being the expected number of occur-
rences of clade X in environment A, OX the total
number of occurrences of taxon X, EnvA the total
number of localities for environment A recorded in
the dataset, and EnvT the total number of localities
(and thus environments) sampled (see Waite,
2000; Butler and Barrett, 2008). To test whether
the recorded number of occurrence of the distinct
taxa significantly deviates from the expected val-
ues, we used Pearson’s Chi square test (Waite,
2000). In order to increase sample size, we anal-
ysed occurrence data for the Middle and Late
Jurassic for the different clades together, as the
reliability of the Chi square test decreases with low
sample sizes, and is not given for sample sizes of
five or lower in any given data cell (Hammer and
Harper, 2006).
Institutional abbreviations. BYU, Brigham Young
University, Provo, Utah, USA; CM, Carnegie
Museum of Natural History, Pittsburgh, USA; IVPP,
Institute for Vertebrate Paleontology and Paleoan-
thropology, Beijing, China; MNHN, Muséum
national d’Histoire naturelle, Paris, France; MNN,
Musée National du Niger, Niamey, Niger; NHMUK,
Natural History Museum, London, UK; OUMNH,
Oxford University Museum of Natural History,
Oxford, UK; USNM, United States National
Museum, Washington D.C., USA; WMN, LWL-
Museum für Naturkunde, Münster, Germany
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
8
SYSTEMATIC PALAEONTOLOGY
DINOSAURIA Owen, 1842
THEROPODA Marsh, 1881
MEGALOSAUROIDEA (Fitzinger, 1843)
MEGALOSAURIDAE Fitzinger, 1843
WIEHENVENATOR gen. nov.
zoobank.org/95638CFF-5618-4D31-9086-D821F6EE6B39
Etymology. Wiehen, for the Wiehengebirge, a
chain of hills south of Minden, where the holotype
specimen was found and venator, Latin for hunter.
The gender of the genus is masculine.
Type species. Wiehenvenator albati sp. nov.
Diagnosis. As for type and only known species
(see below).
Wiehenvenator albati sp. nov.
zoobank.org/262FA776-9ABC-4565-9A17-931CB4BEFBFC
Etymology. The species epithet honours Friedrich
Albat, who found the holotype specimen.
Holotype. Fragmentary skull and skeleton of a sin-
gle individual; right premaxilla (WMN P27475),
right maxilla (WMN P27504), right lacrimal (WMN
P27457), right postorbital (WMN P27477), (?)ante-
rior ramus of right quadratojugal (WMN P27470),
partial right dentary (WMN P27461, 27462, 27466),
six isolated teeth (WMN P27454, 27456, 27459,
27467, 27473, 27483), three caudal vertebrae
(WMN P27499, 27500, 27501), five dorsal ribs and
rib fragments (WMN P27464, 27465, 27476,
27480, 27503), a pair of fused posterior medial
gastralia (WMN P27455), a manual phalanx (WMN
P27482), both fibulae (WMN P27479, 27502), right
astragalus (WMN P27458), and a partial right cal-
caneum (WMN P27484). Two further partial caudal
vertebrae (WMN P29131, 47417) were found at
different times in the float at the type locality and
probably belong to the same individual.
Type locality and horizon. Former Pott quarry,
Lutternsche Egge, near Minden, north-eastern
Northrhine-Westphalia, Germany. The bone-bear-
ing layer is a condensation horizon with abundant
bivalves of the species Gryphaea dilatata in the
middle Ornatenton, Erymnoceras coronatum
ammonite zone, middle Callovian (Riegraf, 1994).
Diagnosis. Large megalosauroid theropod diag-
nosable by the following autapomorphies: Lacrimal
with small oval depression in the antorbital fossa
anterior to the lacrimal fenestra; very short and
high anterior process of the lacrimal, its length
being less than half the height of the bone; postor-
bital with a transversely notably concave orbital
facet in the dorsal part of its anterior side, with
markedly raised lateral and medial margins;
oblique ridge on the medial side of the fibula at
about the level of the iliofibularis tubercle; proximal
part of the ascending process of the astragalus
deflected laterally, resulting in a marked kink in the
lateral margin of this process.
Several further characters can also be used to
diagnose the new taxon; although at least several
of them are found in some other non-coelurosau-
rian theropod taxa, and the distribution of others is
unclear due to lack of detailed descriptions, their
combination is unique to Wiehenvenator albati:
Anterior margin of the nasal process of the pre-
maxilla offset from anterior margin of premaxillary
body by a slight concavity (also present in Sciuru-
mimus); anteriormost premaxillary tooth consider-
ably smaller than second premaxillary tooth (also
present in spinosaurids); medial premaxillary fora-
men placed over the second alveolus, not the third;
maxillary antorbital fossa reduced; small pneu-
matic depression (excavatio pneumatica) on the
ascending process of the maxilla (also present in
Ceratosaurus and some allosauroids).
Description
The bones are generally well-preserved and
largely undistorted, but suffered from recent weath-
ering, so that they show numerous fractures and
are sometimes preserved in several pieces. Some
of the elements are overgrown by marine inverte-
brates (Gryphaea, serpulids, brachiopods), testify-
ing to subaqueous exposure before burial.
Skull. The sparse cranial material only allows for a
tentative reconstruction of the skull (Figure 4).
However, the material shows that the skull was
rather low and long, as it is the case in most mega-
losauroids (Carrano et al., 2012). The nares was
obviously anteroposteriorly elongated and rather
large, and the antorbital fenestra was ventrodor-
sally low and also elongated anteroposteriorly. The
orbit was most probably a high oval in outline, but
there is no evidence for a ventral narrowing, result-
ing in a keyhole-shaped orbit, as it is present in
several large theropod dinosaurs, such as Monolo-
phosaurus (Brusatte et al., 2010a), Allosaurus
(Gilmore, 1920; Madsen, 1976a) or Tyrannosaurus
(Osborn, 1912; Molnar, 1991; Brochu, 2002).
Premaxilla. Most of the body of the right premax-
illa and the ventral part of the nasal process are
preserved (Figure 5). The posterior border of the
bone and the subnarial process are missing, and
the premaxillary alveoli are broken open medially.
The bone preserves three alveoli; assuming that
originally four alveoli were present, as in the vast
majority of non-avian theropods (Currie and Zhao,
1993), an estimated 30-40 mm of the premaxillary
PALAEO-ELECTRONICA.ORG
9
body is missing posteriorly. Thus, the body was
probably rectangular to quadrangular in outline and
approximately as long as high (128 mm between
the ventral border of the nares and the alveolar
border). The anterior margin of the premaxillary
body is slightly convex and forms an almost right
angle with the alveolar margin. The base of the
nasal process is almost vertical over its ventral-
most c. 30 mm, but flexes slightly posterodorsally
in its dorsal part; approximately 60 mm of the pro-
cess are preserved in total. There is a slight con-
cavity in lateral outline between the anterior margin
of the premaxillary body and the anterior margin of
the nasal process (Figure 5.1, 5.2). In the vast
majority of theropods, including Torvosaurus, in
which the general shape of the premaxilla is similar
(Britt, 1991), the anterior margin of the body and
the process are confluent; a similar small concavity
is only found in the early juvenile holotype of Sci-
urumimus albersdoerferi (Rauhut et al., 2012). The
narial border is confluent between the dorsal mar-
gin of the premaxillary body and the posterior mar-
gin of the nasal process, so that the anteroventral
margin of the external nares was gently concave.
The lateral surface of the premaxillary body is
slightly convex dorsoventrally and more notably so
anteroposteriorly. Although the bone surface is not
smooth, it lacks the strong lateral ornamentation
typical for abelisaurids and carcharodontosaurids
(e.g., Bonaparte et al., 1990; Sampson and Wit-
mer, 2007; Carrano et al., 2012). A strongly
depressed subnarial fossa is absent, but there is a
smooth, dorsolaterally inclined surface in the dor-
sal third of the lateral side. Below this surface, the
bone is, unfortunately, too damaged to identify any
border of this narial facet. Several small foramina
are present on the lateral surface, and there is at
least one larger, slit-like foramen at the alveolar
border that opens anteriorly (Figure 5.1). Another
large foramen (8 mm long and 9 mm high) is pres-
ent just at the base of the nasal process, approxi-
mately at the mid-width of the latter (Figure 5.1), as
in Dubreuillosaurus (Allain, 2002) and many other
basal tetanurans. From the foramen, a slight
depression extends ventrally, where it becomes
wider and shallower and flexes posteroventrally. At
least two smaller foramina are placed in this
depression. The transverse thickness of the pre-
maxilla is slightly reduced at the level of the large
foramen at the base of the nasal process, resulting
in a slightly concave lateral outline in anterior view
in this area (Figure 5.3). This concave area coin-
cides with the slight concavity in the anterior mar-
gin described above.
From the large foramen at the base of the
nasal process, a low ridge extends dorsally and
then flexes posterodorsally to join the posterior
margin of the nasal process; this ridge obviously
marks the anterior margin of the narial fossa. Ante-
rior to the ridge, the lateral surface of the nasal pro-
cess is strongly convex anteroposteriorly in the
FIGURE 4. Tentative reconstruction of the skull of Wiehenvenator albati, with the recovered elements shown in their
approximate relation to each other. Scale bar equals 10 cm.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
10
basal part of the process, but becomes flattened
dorsally.
Only few details of the medial side of the pre-
maxilla can be established, due to the breakage of
the medial wall of the alveoli (Figure 5.2). The
interpremaxillary suture is marked by a flat medial
surface of the nasal process, the anterodorsal sur-
face of the premaxillary body, and the anterior mar-
gin. The preserved parts of this suture indicate that
it extended over approximately the anteriormost
two alveoli, and thus slightly less than the half
length of the bone. Together with the general
shape of the premaxilla, this extensive suture indi-
cates a narrow anterior end of the snout.
At the dorsal end of the premaxillary body, the
interpremaxillary suture seems to border the inter-
nal opening of the foramen at the base of the nasal
process, though the anterior border of this foramen
is damaged. This internal opening is slightly larger
(c. 10.3 mm high) than the external opening of the
foramen and is placed further posteriorly and
slightly ventral to the external opening (Figure 5.2),
so that this foramen forms a short, anterodorsally
directed channel through the dorsal portion of the
premaxillary body. The internal opening of the fora-
men is placed above the posterior end of the sec-
ond alveolus, in contrast to Torvosaurus (Britt,
1991), Dubreuillosaurus (Allain, 2002), Majunga-
saurus (Sampson and Witmer, 2007), Marshosau-
rus (Madsen, 1976b), Genyodectes (Rauhut,
2004), and many other theropods, where it is
placed above the third alveolus.
The anterior, external and most of the poste-
rior margin of three premaxillary alveoli are pre-
served (Figure 5.2). The second alveolus is the
highest, its height (104 mm) being more than three-
fourths of the height of the premaxillary body. The
anteroposterior width of this alveolus is approxi-
mately 30 mm ventrally. Whereas the third alveolus
is only insignificantly lower and approximately as
wide as the second alveolus, the first alveolus is
markedly smaller, being approximately 66 mm high
and c. 20 mm wide. A similar condition is seen in
spinosaurids (e.g., Charig and Milner, 1997), but is
otherwise not present in megalosauroids. The
tooth row is slightly curved, with the first alveolus
being placed notably medially in respect to the
level of the third alveolus (Figure 5.4). The border
between alveoli is marked by this interalveolar
bone that thickens medially; however, not enough
FIGURE 5. Right premaxilla of Wiehenvenator albati in lateral (1), medial (2), anterior (3) and ventral (4) views. Abbre-
viations: en, external nares; f, foramen; ips, interpremaxillary suture facet; np, nasal process; numbers A1 to A4 indi-
cate alveoli. Scale bar equals 50 mm.
PALAEO-ELECTRONICA.ORG
11
of the medial part of the alveoli is preserved to say
anything about the presence and morphology of
interdental plates. Of the presumably last (fourth)
alveolus, only a small dorsal part of the anterior
border is preserved (Figure 5.2). Nothing can be
said about the paradental groove.
Maxilla. The right maxilla is preserved in six
pieces, which together account for almost the
entire element, with only minor parts of the antero-
ventral and posterodorsal ends, the anteromedial
process, and the dorsal part of the ascending pro-
cess being missing (Figures 6, 7). The maxilla is
elongate, with a total length of approximately 500
mm and a notably high preantorbital body. The
height from the alveolar border to the highest part
of the ascending process is 230 mm. The bone is
notably robust, the maxillary body being maximally
c. 45 mm wide at the level of the ascending pro-
cess. The maxilla has a total of 13 tooth positions,
with the tooth row having a total length of 410 mm.
The preantorbital body (see Hendrickx and
Mateus, 2014a) accounts for approximately 180
FIGURE 6. Right maxilla of Wiehenvenator albati in lateral (1) and medial (2) views. Abbreviations: af, antorbital
fossa; afo, alveolar foramen; amp, base of anteromedial process; ap, ascending process; ep, excavatio pneumatica;
f, foramen; iv, invertebrate; jf, jugal facet; pdr, paradental ridge; pmr, promaxillary recess; pro, promaxillary foramen.
Scale bar equals 100 mm.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
12
mm of the total length of the bone. The anterior
ramus is approximately 140 mm long and the same
in height at about its mid-length. However, its dor-
sal border rises gradually from the premaxillary
contact to the base of the ascending process.
Thus, the anterior height of the ramus is approxi-
mately 111 mm, while it is c. 170 mm high just ante-
rior to the ascending process. The premaxillary
contact is slightly inclined posterodorsally, so that
its dorsal end is placed at about the level of the
posterior margin of the first alveolus, very similar to
the situation in Torvosaurus tanneri (Britt, 1991).
The dorsal margin of the anterior ramus is very
slightly convex up to the point where it flexes in a
gentle concave arch into the anterior margin of the
ascending process. This point is placed above the
anterior margin of the fourth alveolus. The anterior
margin of the ascending process is slightly con-
cave at its base, but flexes posterodorsally in its
dorsal part. The point of flexure is marked as a kink
in the anterodorsal margin of the ascending pro-
cess, as in the megalosaurids Dubreuillosaurus
(Allain, 2002) and Duriavenator (Benson, 2008),
and in some non-megalosaurid theropods, such as
Coelophysis rhodesiensis (Raath, 1977) and
Monolophosaurus (Brusatte et al., 2010a). Poste-
rior to the kink, the margin of the ascending pro-
cess is straight over the preserved 35 mm and
ascends considerably less steeply posterodor-
sally. The ventral margin of the maxilla is very
slightly convex over the alveolar border, with slight,
irregular undulations. Posterior to the alveolar mar-
FIGURE 7. Stereophotographs of the right maxilla of Wiehenvenator albati in medial (1) and lateral (2) views.
PALAEO-ELECTRONICA.ORG
13
gin, the ventral margin flexes ventrally in the area
of the contact with the jugal.
The internal antorbital fenestra invaginates
the maxilla posteriorly. It was obviously a consider-
ably long, but relatively low opening, being longer
than high. The ventral margin of the opening is
straight and descends slightly posteroventrally.
Thus, the dorsal and ventral margins of the jugal
ramus of the maxilla converge somewhat posteri-
orly, though less notably than in other theropods,
such as Ceratosaurus (Gilmore, 1920), Allosaurus
(Madsen, 1976a), or Acrocanthosaurus (Eddy and
Clarke, 2011). At its anterior end, the jugal ramus is
considerably lower (123 mm) than the anterior
ramus of the maxilla. It tapers to a height of 74 mm
at the level of the 11th alveolus, close to the poste-
rior end of the tooth row. Although the posterodor-
sal end of the jugal ramus is somewhat damaged,
it can be said that the margin of the fenestra flexes
abruptly ventrally towards the jugal suture posteri-
orly. Thus, the jugal ramus of the maxilla is remark-
ably similar to that of Torvosaurus gurneyi
(Hendrickx and Mateus, 2014a).
As in the vast majority of non-avian thero-
pods, the antorbital fenestra is surrounded by a
maxillary antorbital fossa (Figures 6.1, 7.2). How-
ever, in comparison with most tetanuran theropods,
this fossa is very small in Wiehenvenator, similar to
the situation in Torvosaurus (Britt, 1991), abelisau-
rids (e.g., Sampson and Witmer, 2007), and
derived carcharodontosaurids (e.g., Coria and Cur-
rie, 2006). The maximal height of the fossa ventral
to the antorbital opening at the anterior end of the
jugal ramus is 25 mm, and it gradually tapers pos-
teriorly and disappears at about the level of the
10th alveolus. The fossa is mainly marked as a
slightly dorsolaterally inclined surface that is set off
from the lateral surface of the maxilla by a low,
rounded eminence (Figures 6.1, 7.2, 8). Although
the internal wall of the antorbital fossa is somewhat
damaged anteriorly, enough is preserved to indi-
cate that the fossa was reduced in the anteroven-
tral end of the antorbital opening. This contrasts
with the situation in the vast majority of theropods,
in which the maxillary antorbital fossa anterior to
the internal antorbital opening accounts for 10% of
the length of the latter or more. The fossa extends
onto the posterior surface of the ascending pro-
cess, where, in the preserved ventral part, its sur-
face faces posterolaterally rather than strictly
laterally (Figures 6.1, 7.2). As in other theropods,
the anterior margin of the antorbital fossa extends
onto the ascending process up to the level of the
kink in the dorsal margin, from where on the nasal
would have formed the dorsal margin of this fossa.
The lateral surface of the maxilla is largely
smooth. It is very slightly convex dorsoventrally in
the anterior ramus, but very slightly concave in the
jugal ramus. A very slight, triangular depression is
present on the lateral surface of the base of the
ascending process. The lateral surface is pierced
by numerous foramina (Figures 6.1, 7.2). Antero-
dorsally, there is a large, anteriorly and slightly dor-
sally facing foramen towards the dorsal margin of
the anterior ramus, at about its mid-length. A nota-
ble, but shallow depression extends from this fora-
men anteroventrally onto the dorsal fourth of the
anterior end of the anterior ramus. Another very
conspicuous foramen is found some 27 mm from
the anterior margin of the maxillary body at about
the mid-height of the anterior ramus, approximately
at the level of the border between the first and sec-
ond alveolus. It faces ventrally and very slightly
anteriorly and continues as a deep channel antero-
ventrally up to the break in the anteroventral mar-
gin of the bone. Apart from these very conspicuous
foramina, numerous large, ventrolaterally opening
foramina are present along the tooth row. They are
arranged in a zig-zag pattern with alternating lower
and higher foramina. The lower foramina are offset
from the alveolar margin by minimally 17 mm,
whereas the upper foramina extend up to 40 mm
from the alveolar margin. A further foramen, similar
in size and morphology to these neurovascular
foramina, is present above the fourth alveolus,
some 60 mm above the alveolar margin. The last
two foramina are placed above the 8th and 10th
alveolus, respectively, and do not follow the zig-
zag pattern, being placed at approximately the
FIGURE 8. Stereophotographs of the promaxillary fora-
men in the right maxilla of Wiehenvenator albati in pos-
terodorsal view. Abbreviations as in Figure 6. Scale bar
equals 50 mm.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
14
same level, some 48 mm above the alveolar mar-
gin.
Only parts of the sutural contacts to other
bones are preserved. The premaxillary suture is
represented mainly by a small section of its mid-
height, which forms a transversely convex, anteri-
orly facing surface. The dorsal surface of the ante-
rior end of the anterior ramus of the maxilla is too
strongly weathered to discern any facet for the sub-
narial process of the premaxilla. More posteriorly,
the dorsal surface is better preserved, but no facet
for the subnarial process is present, indicating that
the maxilla might have separated the subnarial
process of the premaxilla and the ventral anterior
process of the nasal and thus formed at least a
small portion of the ventral margin of the external
naris. Towards the base of the ascending process,
at about the level of the border between the third
and fourth alveolus, the facet for the ventral ante-
rior process of the nasal is developed as an antero-
dorsally facing depression. The depression is
marked by raised lateral and medial margins and
tapers anteriorly. On the anterior surface of the
ascending process, this facet becomes notably
deeper, though this might be due to deformation.
Another small facet for the main body of the nasal
is present on the dorsolateral surface of the dorsal-
most preserved part of the ascending process.
This facet narrows slightly anteriorly and extends
up to the rim of the antorbital fossa.
Posteriorly, large parts of the suture with the
jugal are preserved (Figures 6.1, 7.2). The suture
is preserved as an elongate lateral facet bordered
ventrally by a laterally flexed shelf of the ventral
border of the maxilla. This shelf turns dorsally ante-
riorly to enclose a narrow, deep furrow for the
reception of the anterior end of the jugal, as in Tor-
vosaurus gurneyi (Hendrickx and Mateus, 2014a).
Just at the posterior end of the tooth row, the shelf
expands rapidly dorsally to form the lateral surface
of the maxillary body, but the furrow continues
medial to the shelf up to at least the anterior end of
the 11th alveolus and becomes shallower anteri-
orly. Medial to the jugal facet, a shallow, elongate
groove is present on the transversely thickened
posterior end of the maxilla. This groove faces dor-
sally and slightly laterally and probably represents
the contact for the lacrimal.
As it is usual in averostran theropods, addi-
tional pneumatic features are present in the ante-
rior end of the antorbital fossa. Due to the
reduction of the fossa noted above, no maxillary
fenestra or fossa seems to be present, in contrast
to the majority of tetanuran theropods. However, a
large promaxillary foramen is present in the ante-
rior end of the fossa and pierces the base of the
ascending process, leading anteriorly into a large
promaxillary recess within this structure (Figures
6.2, 7.1, 8). The foramen is large and considerably
higher (c. 39 mm) than wide (c. 21 mm). As in
many theropods, it is completely concealed in lat-
eral view by the overhanging anterior border of the
antorbital fossa (Figures 6.1, 7.2). The premaxillary
recess associated with this foramen is triangular in
outline, tapering anteroventrally and thus occupies
the entire base of the ascending process (Figures
6.2, 7.1). A small depression is furthermore pres-
ent dorsal to the promaxillary foramen on the ven-
tral part of the antorbital fossa on the ascending
process and is visible in lateral view (Figures 6.1,
7.2). This depression corresponds in relative posi-
tion to the excavatio pneumatica seen in some
theropods (Witmer, 1997) and might thus represent
this structure. In accordance with the reduced
medial wall of the antorbital fossa, this depression
is smaller and slightly more ventrally placed than
the excavatio pneumatica in most theropods, in
which it is present. It is furthermore bordered medi-
ally by a rather robust wall of bone, in contrast to
e.g., Sinraptor, in which the excavation pneumatica
is only limited by a very thin sheet of bone medially
(IVPP V-10600; Currie and Zhao, 1993)
The medial side of the maxilla is poorly pre-
served, and the medial wall of several alveoli and
the anteromedial process are missing (Figures 6.2,
7.1). As in the premaxilla, the alveoli are very high
and extend dorsally over almost the entire height of
the maxillary body. In accordance with the general
shape of the maxillary body, the height of the alve-
oli increases up to the third alveolus and then grad-
ually decreases again posteriorly. Posterior to the
10th alveolus, the dorsal margin of the maxilla is
thickened medially and extends further ventrally,
resulting in a notable step in the bone between the
10th and the 11th alveolus. The mesiodistal width of
the alveoli increases from approximately 35 mm in
the first alveolus to a maximum of 45 mm in the
third alveolus and then decreases gradually
towards the end of the tooth row (see Table 1).
Several interdental plates are at least partially pre-
served. The plates are clearly separated, in con-
trast to the situation in Torvosaurus (Britt, 1991;
Hendrickx and Mateus, 2014a) and allosauroids.
The medial surface of the interdental plates is
poorly preserved in most elements, but robust dor-
soventral striations are discernible in some plates
(Figures 6.2, 7.1), as they are also present in some
other megalosauroids (Benson, 2010a). A true
PALAEO-ELECTRONICA.ORG
15
paradental groove (‘groove for the dental lamina’ of
Brusatte et al., 2012; ‘nutrient groove’ of Hendrickx
and Mateus, 2014a), as it is present in many thero-
pods is absent, but there is a notable step separat-
ing the interdental plates from the medial wall of
the maxillary body dorsal to the plates, here termed
the paradental ridge. The paradental ridge is visible
in a few places (Figure 6.2); it is placed at about
two thirds of the height of the maxillary body and is
slightly curved, reaching its highest point at about
the third to fourth alveolus and lowering anteriorly,
as in many other megalosaurids (Benson, 2010a).
An enlarged dental foramen (‘nutrient foramen’ of
Hendrickx and Mateus, 2014a) is present between
the second and third alveolus and extends further
dorsally than the paradental ridge (Figures 6.2,
7.1), as in Majungasaurus (Sampson and Witmer,
2007), although this might be somewhat exagger-
ated by erosion (Although we follow Hendrickx and
Mateus [2014a] in the terminology of other parts of
the maxilla, we prefer the terms ‘paradental groove’
and ‘dental foramen’ for these structures associ-
ated with the interdental plates, as they are more
specific than the terms ‘nutrient groove’ and ‘nutri-
ent foramen’ advocated by these authors).
Although none of the interdental plates is com-
plete, their ventral border was clearly placed con-
siderably dorsal to the lateral alveolar margin, as in
Torvosaurus (Britt, 1991) and Megalosaurus (Ben-
son, 2010a). The anteromedial process is broken
off, but its base is placed notably above the inter-
dental plates (Figure 6.2), as in Torvosaurus (Britt,
1991) and Megalosaurus (Benson, 2010a). Poste-
riorly, some longitudinal striations are present on
the dorsomedial side of the thickened posterior end
of the maxillary body; these striations probably rep-
resent the posterior part of the suture with the pala-
tine. If a large neurovascular opening was present
on the dorsomedial margin of the jugal process, as
it is the case in Torvosaurus (Hendrickx and
Mateus, 2014a) and other basal tetanurans, cannot
be said, as this region is poorly preserved (Figures
6, 7).
The only functional tooth preserved occupies
the fourth alveolus, though the crown sits approxi-
mately with its half-height still above the alveolar
border. Thus, it currently protrudes 47 mm beyond
the alveolar border, but the total height of the
crown is approximately 80 mm. Replacement teeth
are present in the first, second, third, fourth, and
fifth alveolus, in different stages of eruption:
Whereas in the second alveolus, the tip of the
crown just protrudes beyond the alveolar border,
the fourth alveolus shows the upper part of the
crown of a new replacement tooth in the upper part
of the alveolus lingual to the functioning tooth. The
teeth are described in detail below.
Lacrimal. As it is usual in theropods, the lacrimal is
an inverted L-shaped element, with a preserved
height of approximately 180 mm (Figure 9). A small
portion of the ventral end seems to be missing, but
this missing portion should not be more than a few
cm. However, in comparison with most taxa, the
anterior process is remarkably short and dorsoven-
trally high; the total length of the dorsal part of the
lacrimal (122 mm) is approximately 68% of the pre-
served height of the bone. This abbreviated shape
is most probably not due to breakage, as the mar-
gins of the process seem to be intact. Furthermore,
the anterior process tapers anteriorly to form a
broad tip that most probably articulated with the
forked posterior end of the ascending process of
the maxilla, as in other theropods, so the shape is
also consistent with the process being complete.
The dorsal margin of the process is convex over its
entire length. The ventral margin is slightly con-
cave in the area of contact with the maxilla, and
then becomes slightly convex, before it curves in a
gradual concave arch into the anterior margin of
the ventral process at about half the length of the
anterior process. The facet for the articulation with
the maxilla on the ventral part of this anterior pro-
cess is marked by a notable step on the lateral
side.
Although a marked lacrimal horn is absent,
the posterodorsal margin of the bone is gently con-
vex, and there is a small, rounded dorsal protrusion
at the posterodorsal corner (Figure 9.1). The orbital
margin of the ventral process is gently concave
over its entire length, whereas the anterior margin
is slightly concave in its dorsal half and slightly
convex in its ventral half. Thus, the ventral end of
the ventral process is more markedly expanded
posteriorly than anteriorly. The anteroposteriorly
shortest part of the ventral process (28 mm) is
found at about its mid-height. Whereas the anterior
process forms a robust, but flat, triangular plate of
TABLE 1. Anteroposterior width of the maxillary alveoli of Wiehenvenator albati (in mm).
Alveolus 1 2 3 4 5 6 7 8 9 10 11 12 13
Width c. 35 c. 39 c. 45 c. 40 37 35 30 25 23 c. 18 c. 20 13 10
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
16
bone, the ventral process is notably thickened
transversely.
The lateral surface of the lacrimal is
depressed by the antorbital fossa on its anterodor-
sal corner and most of the anterior process and on
the anterior side of the ventral end of the ventral
process (Figure 9.1). Unlike the situation in Torvo-
saurus (Britt, 1991), spinosaurids (Charig and Mil-
ner, 1997; Sues et al., 2002), and Sciurumimus
(Rauhut et al., 2012), but as in most theropods,
including Ceratosaurus (Madsen and Welles,
2000), Dubreuillosaurus (Allain, 2002), Afrovenator
(Sereno et al., 1994) and allosauroids (Madsen,
1976a), the dorsal and ventral parts of the antor-
bital fossa are not confluent on the anterior side of
the ventral process, but separated by an anteriorly
convex margin of the lateral surface of the lacrimal
body (‘lateral blade’ of the lacrimal of Britt, 1991).
FIGURE 9. Right lacrimal of Wiehenvenator albati in lateral (1; stereophotographs), medial (2), anterior (3; stereo-
photographs), posterior (4; stereophotographs), and dorsal (5) views. Abbreviations: af, antorbital fossa; d, depres-
sion; fo, foramen; lf, lacrimal fenestra; prf, facet for prefrontal; r, ridge. Scale bar equals 50 mm.
PALAEO-ELECTRONICA.ORG
17
However, whereas the ‘lateral blade’ protrudes into
the antorbital opening in some theropods (e.g.,
Gilmore, 1920), it only insignificantly overhangs the
medial side in Wiehenvenator, similar to the situa-
tion in Dubreuillosaurus (Allain, 2002). A shallow
groove on the anterior side of the ventral process
separates the ‘lateral blade’ from the medial part
and thus connects the dorsal and ventral portions
of the antorbital fossa (Figure 9.3). A small fora-
men in the middle of this groove most probably
represents the anterior exit of the lacrimal foramen.
The ventral part of the antorbital fossa is triangular
in outline and subdivided by a low, almost vertical
ridge into an anterior and a posterior concavity
(Figure 9.1). The anterior concavity is also sepa-
rated from the margin of the antorbital fenestra by
a very slightly raised edge.
In the posterodorsal corner of the lacrimal, a
large lacrimal fenestra expands from the antorbital
fossa into the bone. Its lateral wall is broken off,
revealing that the lacrimal fenestra led into a sin-
gle, more or less round pneumatic chamber (Fig-
ure 9.1). A small (11 mm long and 8 mm high) but
deep oval depression is found anterior to the exit of
the lacrimal fenestra within the antorbital fossa on
the lateral side of the base of the anterior process.
Whereas the dorsal margin of the lacrimal is
slightly thickened directly in front of the lacrimal
fenestra to border the antorbital fossa, this thicken-
ing rapidly disappears anteriorly, so that the entire
lateral surface of the anterior process is occupied
by the fossa, in contrast to Allosaurus (Gilmore,
1920), Torvosaurus (Britt, 1991), and many other
theropods.
Medially, the surface of the anterior process is
slightly convex dorsoventrally. A shallow depres-
sion along the dorsal border of the process
becomes more marked in the posterodorsal corner
of the bone and then flexes ventrally and slightly
anteriorly; this depression marks the contact for the
prefrontal (Figure 9.2). The posterodorsal margin
of the bone is somewhat thickened (Figure 9.5).
From this thickened margin, a notable ridge contin-
ues on the ventral process obliquely across the
medial surface. The ridge begins at about two
thirds of the height of the element at the posterior
border and extends anteroventrally until it meets
the anterior border towards the ventral end,
becoming lower ventrally. The area posterior to the
ridge faces more posteriorly than medially in its
dorsal part, but gradually twists to face medially in
the ventral portion. The posterior border of the
bone is more notably thickened than the anterior
border. It is flat in its dorsal part, but there is a nota-
ble step extending ventrolaterally from the point
where the ridge described above begins. This ridge
meets the lateral margin of the bone just below the
mid-height of the bone and thus borders the pos-
teromedially facing surface described above later-
ally.
As the ventral end of the bone is damaged,
nothing can be said about the exact contacts with
the jugal ramus of the maxilla and the jugal.
Postorbital. As with the other cranial elements, the
postorbital (Figure 10) is markedly robust. It is a T-
shaped element with a long ventral process and
short anterior and posterior processes dorsally.
The maximal anteroposterior length of the bone
across the dorsal processes is 131 mm, whereas
the maximal height of the bone is 190 mm. The
ventral process is flexed slightly anteriorly, so that
its anterior border is gently concave over its entire
length and the posterior border is slightly convex.
Dorsally, the posterior border flexes posteriorly in a
gradual concave arch into the posterior process.
The latter is triangular in outline and tapers posteri-
orly. The anterior process is more robust and rect-
angular in lateral outline. Its dorsal margin forms a
convex margin that is confluent with the dorsal
margin of the posterior process, in contrast to Allo-
saurus (Madsen, 1976a) and many other thero-
pods, in which the dorsal margin of the anterior
process is concave, and the margin of the posterior
process convex. The two processes are subequal
in length, the posterior process being 62 mm long
and the anterior process 69 mm (both measured
from the highest point of the bone, which roughly
coincides with the mid-point of the ventral pro-
cess).
As in many theropods, there is a raised,
slightly rugose ‘brow’ on the lateral side of the
anterior process (Figure 10.1). This brow extends
approximately onto the half-width of the dorsal end
of the ventral process and is bordered posteriorly
by a marked depression. This depression starts at
approximately the half-height of the ventral process
and expands over the confluence of the processes
to the base of the posterior process, where the
bone becomes flat. The edge between the ‘brow’
and this depression is curved posterodorsally in its
dorsal portion and becomes lower posteriorly.
The ventral process is markedly robust, being
thicker transversely (30 mm at mid-height) than
anteroposteriorly (26 mm). The ventral half of the
process is notably convex anteroposteriorly both
laterally and medially, whereas the orbital margin is
flattened transversely. On the posterior side of the
ventral process, a broad, longitudinal groove marks
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
18
FIGURE 10. Right postorbital of Wiehenvenator albati in lateral (1), anterior (2), medial (3), posterior (4), and dorsal
(5) views (all stereophotographs). Abbreviations: d, depression, ff, frontal facet; jf, jugal facet; lf, laterosphenoid
facet; of, orbital facet; sob, supraorbital brow; stf, supratemporal fossa. Scale bar equals 100 mm.
PALAEO-ELECTRONICA.ORG
19
the contact with the dorsal process of the jugal
(Figure 10.4). The groove is deeper medially than
laterally and becomes narrower ventrally. The
medial wall of the groove is slightly higher than the
lateral wall, so that its edge is visible in lateral view
(Figure 10.1). Thus, the suture for the jugal is U-
shaped in cross-section, as in other megalosaurids
(Sereno et al., 1994; Rauhut, 2003). Whereas the
lateral edge of the groove is approximately level
with the lateral side of the ventral process, the
medial wall is slightly offset laterally from the
medial side. Dorsally, a low oblique ridge extends
from the dorsal end of the medial wall dorsolater-
ally and meets the lateral edge at about two thirds
of the height of the process. From the confluence
of these two edges, the posterolateral margin of
the bone forms a narrow, but stout ridge connect-
ing the ventral process with the posterior process.
Medial to this ridge, the posterior side of the bone
becomes markedly concave transversely towards
the dorsal supratemporal fossa (Figure 10.4).
The posterior process is considerably more
slender transversely than the ventral and anterior
process. Its posterior tip is somewhat rounded in
cross-section, with the lateral surface being slightly
offset from the lateral surface of the main body of
the process. A flattened surface for the overlap of
the dorsal anterior process of the squamosal is
present on the dorsal surface of the process,
whereas the ventral facet is slightly convex trans-
versely and faces very slightly medioventrally. Both
facets extend anteriorly to approximately the level
of the posterior border of the ventral process.
As noted above, the anterior side of the ven-
tral process is flat, but there is an unusual, conspic-
uous, round facet in the dorsal part of this surface
(Figure 10.2). This facet is strongly concave both
dorsoventrally and transversely and extends onto
the anterior process dorsally. It has markedly
raised lateral and medial margins, with the medial
side expanding anteromedioventrally, so that it is
visible in lateral view anterior to the lateral margin.
The margin of this medial expansion forms a sharp
ridge, the ventral end of which curves ventrolater-
ally onto the anterior side of the ventral process,
ending some 12 mm below the lateral margin. The
latter is stout and rounded and curves slightly
medially in its ventral end, being offset from the
anterolateral edge of the ventral process by a small
step.
The anterior process is markedly expanded
transversely to a maximal width of 57 mm and
houses the anterolateral part of the supratemporal
fossa dorsally (Figure 10.5). The fossa is deeply
excavated and has a steep lateral margin, with the
lateral edge becoming slightly thicker anteriorly.
The fossa has a slightly concave lateral margin, but
does not extend onto the medial side of the poste-
rior process. Dorsally, the supratemporal fossa has
a flat ventral floor anteriorly that abruptly flexes
ventrally into the posterior concavity on the dorsal
part of the ventral process at about the mid-width of
the latter.
The suture with the frontal is largely obscured
by erosion and breakage, but there is a large,
medially facing facet for the laterosphenoid on the
confluence of the anterior and ventral processes
(Figure 10.2). This facet is obliquely elongate oval
in outline, and seems to have been deeply con-
cave, but has also suffered from erosion, so no
details of the articular surface can be made out.
Quadratojugal. A stout, finger-like bone probably
represents the anterior (jugal) ramus of the right
quadratojugal (Figure 11). The element is pre-
served over a length of approximately 12 cm, with
the posterior end showing signs of erosion, rather
than a clear break. It tapers anteriorly, being 37
mm high at the posterior end, but only 14 mm at a
point c. 10 mm from the anterior end, from where
the anterior end is gently rounded. In lateral view,
the anterior portion is very slightly flexed ventrally,
in contrast to the situation in many theropods,
where the anterior ramus of the quadratojugal is
often slightly flexed dorsally (e.g., Currie and Zhao,
1993; Sampson and Witmer, 2007). In dorsal or
ventral view (Figure 11.3, 11.4), the bone is slightly
curved medially, as it is the case in many theropod
quadratojugals. As with all cranial bones of Wie-
henvenator, the bone is notably robust, being 14
mm wide transversely towards the anterior end.
Whereas the dorsal margin of the element stays of
more or less subequal width over its entire length,
the ventral part becomes thinner and the ventral
edge has a width of only 6 mm in its posterior part.
At the area of the eroded connection to the dorsal
process, the entire bone is again considerably
thickened to approximately 14 mm.
The lateral surface is slightly convex dorso-
ventrally in its anterior portion and the ventral two
thirds of the posterior part, but curves medially in
the dorsal third in the posterior two-thirds of the
process (Figure 11.1), to meet the medial surface
in a sharp angle towards the posterior end of the
preserved portion. The medial side is both antero-
posteriorly and dorsoventrally slightly concave in
its ventral part, whereas the dorsal margin forms a
stout rib anteriorly and a straight surface towards
the posterior end (Figure 11.2).
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
20
The contact facets for the jugal are very simi-
lar to those seen in Majungasaurus (Sampson and
Witmer, 2007). On the dorsal surface of the ante-
rior end, a well-developed, broad, but rather shal-
low longitudinal groove represents the facet for the
dorsal posterior prong of the jugal (Figure 11.3).
This groove begins posterior to the anteriorly
rounded tip of the bone and extends for approxi-
mately 30 mm posteriorly before it fades out into
a broad, flattened surface, which becomes increas-
ingly inclined laterally posteriorly. Based on the
morphology of this facet, the dorsal prong of the
jugal overlapped the quadratojugal probably for 50-
60 mm. The contact for the ventral posterior prong
of the jugal is developed as a ventromedially facing
facet anteriorly that becomes gradually thinner
posteriorly and turns onto the ventral edge, where
it continues over the entire length of the preserved
portion of the quadratojugal as a flattened ventral
surface (Figure 11.2, 11.4). Thus, the ventral poste-
rior prong of the jugal was obviously considerably
longer than the dorsal prong, as in most theropods.
Dentary. The right dentary is present, but very
poorly preserved (Figure 12). The bone was found
in three pieces, which together account for approx-
imately 485 mm of its length. Approximately 275
mm of these represent the tooth-bearing portion of
the dentary, whereas the posterior part is only rep-
resented by its ventral portion, which does not
show any signs of alveoli (Figure 12.3). It is unclear
whether any part in between these portions is
missing, but if so, it should be a minor part. In the
anteriormost preserved part of the main dentiger-
ous portion of the bone, the lateral side flexes
slightly medially and the ventral margin starts to
curve dorsally, indicating that this part is close to
the anterior end of the dentary. A small fragment
obviously represents a portion even more anteri-
orly, with an anteroposteriorly narrow alveolus and
an almost entirely anteriorly facing lateral side, but
again it cannot be said how much is missing
between this fragment and the main section. How-
ever, given the proximity of this fragment to the
main section of the dentary in the quarry and the
indications that the anterior part of the main section
is already close to the anterior end, not much
seems to be missing, and we assume that the pre-
served one and one-third alveoli of this piece are
continuous with the alveoli of the main section.
At least nine alveoli are present in the pre-
served parts of the tooth row (Figure 12.3). The
first alveolus is considerably smaller (c. 14 mm
anteroposterior length and two-thirds to three-
fourths of the height of the other alveoli) than the
more posterior tooth sockets. The second alveolus
cannot be measured with any certainty, as a small
part of it might be missing. In the main section of
the dentary, the presumably third alveolus is nota-
bly larger (35 mm anteroposterior length) than the
more posterior alveoli, which remain of subequal
size throughout the preserved portion (27-28 mm
anteroposterior length). Thus, the alveoli in the
dentary are consistently lower and narrower than
those in the maxilla, indicating that the dentary
teeth might have been somewhat smaller than the
corresponding maxillary teeth, as in Dilophosaurus
(Welles, 1984), Ceratosaurus (Gilmore, 1920),
Dubreuillosaurus (Allain, 2002), Baryonyx (Charig
and Milner, 1997), Eustreptospondylus (Sadleir et
al., 2008), and probably Torvosaurus (Britt, 1991;
though note that the maxilla BYU 9122 does not
necessarily represent the same individual as the
dentary BYU 2003). The anterior end of the den-
tary is slightly expanded transversely compared to
FIGURE 11. Anterior (jugal) process of the right quadratojugal(?) of Wiehenvenator albati in lateral (1), medial (2),
dorsal (3), and ventral (4) views. Abbreviations: djp, facet for the dorsal posterior prong of the jugal; vjp, facet for the
ventral posterior prong of the jugal. Scale bar equals 100 mm.
PALAEO-ELECTRONICA.ORG
21
the mid-section of the bone (Figure 12.2), which is
consistent with the interpretation that one or sev-
eral of the anterior dentary teeth might have been
larger than the other dentary teeth, as in many
megalosauroids. However, whereas the enlarged
dentary tooth is the third in Eustreptospondylus
(Sadleir et al., 2008), as in Wiehenvenator, Mega-
losaurus has the fourth dentary tooth enlarged
(Benson et al., 2008). In Duriavenator (Benson,
2008) and Dubreuillosaurus (Allain, 2002), the third
dentary tooth is enlarged, but the fourth is more or
less subequal in size, and more distal teeth gradu-
ally become smaller. The main section of the tooth
row has parallel dorsal and ventral borders and is
c. 101 mm high. The lateral side is flat and unorna-
mented, although a few large lateral foramina
seem to be present (Figure 12.1). These foramina
are randomly distributed and are not placed in a
lateral groove, although it cannot be excluded that
such a groove might have been present in a more
posterior part of the dentary, as in Dubreuillosaurus
(Allain, 2002). Ventrally, the lateral side of the bone
flexes gradually into the ventral side, with this flex-
ure being more strongly convex in the anterior part
than the posterior part. In the posterior portion pre-
served, the ventral margin becomes a sharp edge
posteriorly.
In medial view, most of the medial wall, includ-
ing all interdental plates, are missing (Figure 12.3).
As in the premaxilla and maxilla, the teeth in the
tooth-bearing portion were deeply rooted, with the
alveoli extending almost to the ventral border of the
bone. The alveoli are slightly inclined anterodor-
sally, more so in the anterior part of the tooth row.
The ventral margin of the anterior portion of the
dentary flexes medially into the ventral part of the
medial wall. In the central section of the preserved
main part, a slightly depressed and striated area
probably indicates the suture for the splenial. The
posterior part preserved represents the area of the
dentary where the Meckelian groove expands to
occupy most of the height of this bone. Conse-
quently, this portion is transversely thin, plate like,
and has only a slightly thickened ventral margin in
its anterior part. No teeth are preserved in the den-
tary.
Dentition. Apart from the teeth preserved in the
maxilla as noted above (Figure 13.1, 13.2), six iso-
lated teeth of Wiehenvenator are present. All of the
isolated teeth have at least parts of their root pre-
served, and their morphology is consistent with
FIGURE 12. Right dentary of Wiehenvenator albati in lateral (1), ventral (2), and medial (3) views. Scale bar equals
100 mm.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
22
those of the teeth in the maxilla, indicating that they
are all derived from the skeleton (Figure 13.3-9).
One tooth probably comes from the mesial denti-
tion and represents a premaxillary or mesial den-
tary tooth and is described separately below
(Figure 13.10-12).
The lateral maxillary or dentary teeth are
strongly flattened transversely and are consider-
ably recurved, so that the tip of the crown is placed
distal to the distal margin of the base of the crown.
Accordingly, the mesial carina is convex over its
entire length and the distal carina slightly concave.
Both the mesial and distal carinae show serrations.
However, whereas the distal carina extends to the
tooth base, the mesial carina is restricted to the
apical two-thirds of the crown (Figure 13.4, 13.6),
as in all megalosaurids (Hendrickx et al., 2015a)
and many other theropods. In contrast to some
allosauroids, tyrannosauroids and dromaeosau-
rids (Hendrickx and Mateus, 2014b), the basal end
of the mesial carina is straight and does not curve
labially. In the teeth preserved in the maxilla, both
carinae are more or less centrally placed, so that
the teeth are symmetrical in apical view. However,
in several of the isolated teeth (WMN P27483,
27459, 27467), the distal carina is slightly dis-
placed labially from the midline (Figure 13.4). As at
least the teeth WMN P27483 and 27459 are too
large to fit in the dentary, this probably indicates
some variation in this character in the maxillary
teeth. The serrations are poorly preserved in most
specimens. However, where they are preserved,
the denticles are chisel-shaped and relatively low.
There are approximately 15 denticles per 10 mm
on both the mesial and distal carina. No interdenti-
cle sulci or enamel undulations, longitudinal ridges
or grooves, flutes or labial and lingual depressions
(sensu Hendrickx et al., 2015b) are visible on any
of the teeth. However, as the serrations are poorly
preserved in all teeth, it cannot be ruled out that
interdenticle sulci might have been present in at
least some elements and some parts of the serra-
tions, since they are present in the vast majority of
megalosaurids (Hendrickx et al., 2015a), and their
presence can be variable within a single dentition
(Benson, 2010a; Hendrickx et al., 2015a). A rarely
reported feature of these teeth is that the serra-
tions are continuous across the tip of the crown
(Figure 13.9), as in Acrocanthosaurus (Harris,
1998). The denticles crossing the tip are markedly
smaller than those on the central parts of the cari-
nae. If the presence of denticles crossing the tip of
the crown is really rare in theropods has to be
shown by more detailed studies of complete thero-
pod teeth (Hendrickx et al., 2015a; Hendrickx, per-
sonal commun., 2016); in Megalosaurus (OUMNH
J 13506), most tooth tips lack serrations, but this
might simply be due to wear, since one well-pre-
served crown of an erupting replacement tooth
retains such denticles.
The preserved roots are long and robust. In
the most complete tooth, WMN P27483, the crown
height is approximately 73 mm, but the root, as
preserved, is at least 114 mm long (Figure 13.4-6).
The root is continuous with the base of the crown
and not separated by an incision. It remains of sub-
equal mesiodistal width over most of its length, but
narrows slightly towards its basal end. In mesial or
distal view, the widest part of the root is placed
some 20 mm below the base of the crown; from
there on, the root gradually narrows towards the
basal end. There is a shallow longitudinal depres-
sion on either side of the root that extends over its
entire length. The part mesial of this depression is
slightly wider labiolingually than the part distal to it.
On the lingual side of the root, the longitudinal
depression becomes deeper and wider basally,
forming the resorption pit (Hendrickx et al., 2015b)
to accommodate the developing replacement
teeth. In the tooth WMN P27473, the root seems to
be slightly angled in relation to the crown, so that
the latter projects slightly mesially (Figure 13.8).
However, it is unclear if this might not simply be an
artifact of preservation, as the basal part of the
crown and the root are poorly preserved.
The probable premaxillary or anterior dentary
tooth WMN P27456 has parts of the root pre-
served, but the basal part of the labial side of the
crown and this side of the root is missing most of
its enamel and dentine (Figure 13.10-12). The
tooth is considerably smaller than the larger lateral
teeth, with the crown measuring approximately 42
mm in height, as in ceratosaurs (Rauhut, 2004),
tyrannosauroids (Brusatte and Carr, 2016), and
other megalosaurids (Hendrickx et al., 2015a). The
tooth is furthermore less compressed and less
recurved than the lateral teeth, with the tip of the
crown being placed only insignificantly distal to the
distal base of the crown, so that the distal carina is
only slightly concave in its basal part and straight in
its apical two thirds. In this tooth, the crown is
slightly twisted in respect to the root, so that the
mesial carina is displaced lingually and the distal
carina slightly labially (Figure 13.10, 13.12). How-
ever, in contrast to Allosaurus (Madsen, 1976a)
and several other theropods, such as tyrannosau-
roids and dromaeosaurids, the tooth crown in itself
is not asymmetric, but the carinae are placed on
PALAEO-ELECTRONICA.ORG
23
opposing sides, as in other megalosaurids (Hen-
drickx et al., 2015a). In mesial or distal view, the
crown is slightly flexed labially towards its tip.
Whereas the distal carina follows the line of this
curve, the mesial carina is very slightly sigmoidal,
flexing very slightly lingually in the apicalmost part.
Both carinae bear serrations, but they are
poorly preserved. There are approximately 16 den-
ticles per 10 mm on the distal and 14 denticles per
10 mm on the mesial carina, although these counts
should be seen with caution due to the poor pres-
ervation. The eroded bases of the denticles of the
FIGURE 13. Dentition of Wiehenvenator albati. 1, replacement tooth in the 2nd maxillary alveolus; 2, functional tooth
in the 4th maxillary alveolus; 3, probable maxillary tooth with partially preserved root (WMN P27459) in lingual view;
4-6, probable maxillary tooth with complete root (WMN P27483) in distal (4), lingual (5) and mesial (6) views; 7,
mesial (posterior premaxillary or anterior dentary) tooth (WMN P27467) in labial(?) view; 8, maxillary or dentary tooth
(WMN P27473) in labial(?) view; 9, detail of crown apex of WMN P27373, showing the carina that is continuous
across the tip (mesial is to the left); 10-12, mesial (probably premaxillary) tooth (WMN P27456) in distal (10), labial
(11) and mesial (12) views. Abbreviations: idp, interdental plates; pdl, paradental lamina. Scale bars equal 10 mm (1,
2) and 50 mm (3-12; not 9).
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
24
distal carina indicate that these denticles might
have been angled very slightly apically; there is no
indication for such an inclination in the mesial
carina. The tip of the tooth is worn, so it cannot be
established if the denticles might have been contin-
uous over the tip.
The preserved part of the root largely corre-
sponds to that of more posterior teeth. The only dif-
ference might be that there is no indication of a
longitudinal depression on the preserved part of
the lingual side.
The tooth WMN P27467 is somewhat interme-
diate in morphology between this tooth and the
more typical lateral teeth (Figure 13.7) and might
thus represent a more distal premaxillary or an
anterior dentary tooth.
Due to the generally poor preservation of the
surfaces of the tooth crowns, the presence and
structure of possible enamel texture (see Hen-
drickx and Mateus, 2014b; Hendrickx et al., 2015a,
2015b) is difficult to establish. The teeth preserved
in situ in the maxilla do not show any clear pattern
and seem to be largely smooth, although this might
be due to erosion. The most complete isolated
tooth, WMN P27483, seems to have the braided
enamel texture that is typical for megalosaurid
teeth (Hendrickx et al., 2015a) in the basal part of
the crown, but a rather anastomosed texture
(sensu Hendrickx et al., 2015b) in a more apical
part. However, it cannot be ruled out that the latter
texture simply results from erosion of this part of
the tooth enamel.
Vertebrae. Three almost complete and two frag-
mentary caudal vertebrae of Wiehenvenator are
preserved. The most anterior of the more complete
elements, WMN P27501, represents an anterior
mid-caudal vertebra (Figure 14), whereas the other
two vertebrae WMN P27499 and P27500 are
somewhat more posterior elements from the mid-
caudal section (Figures 15, 16). WMN P47417 pre-
serves only the posterior end of an anterior mid-
caudal, whereas WMN P29131 is a poorly pre-
served fragment of a more distal caudal vertebra.
Measurements for the complete vertebrae are
found in Table 2.
The vertebral centrum of MWN P27501 has
several breaks in the anterior part and is missing
most of the posterior articular end (Figure 14). The
centrum is strongly constricted, its minimal width at
about mid-length (50 mm) being only about 45% of
the width of the anterior articular surface (c. 113
mm). The anterior articular surface is very slightly
concave, whereas the posterior surface seems to
be flat. The rim of the anterior articular surface is
flexed slightly laterally. The articular surface is
slightly wider than high and round in outline. Dor-
sally, the neural canal forms a wide, but low inden-
tation into the articular surface. The ventral surface
of the centrum is broad and rounded, without any
ventral keel or ventral groove (Figure 14.4). On the
lateral side of the centrum, a well-developed, but
shallow pleurocentral depression is present on
either side just above the mid-height of the centrum
(Figure 14.1). This depression becomes slightly
deeper posteriorly and is more clearly defined dor-
sally than ventrally. Similar, large, shallow, but
rather well-defined lateral depressions are also
present in the caudal vertebrae of Torvosaurus
(Britt, 1991) and Megalosaurus (NHMUK R 9672,
97673, 9676, OUMNH J 13578, 13579; Benson,
2010a). The broken posterior part of the centrum
shows that there are no internal cavities, in con-
trast to the situation in Ceratosaurus (Madsen,
1976a) and abelisaurids (Rauhut et al., 2003). On
the anterior part of the right side of the centrum, the
neurocentral suture is visible. It extends in a gently
convex arch from the anterodorsal margin of the
centrum posteroventrally for approximately 25-30
mm and then extends in a straight line across the
dorsal part of the centrum. The suture is strongly
interdigitating and completely closed, but still visi-
ble.
The neural arch is relatively low, but becomes
somewhat higher posteriorly. The neural canal is
large and has a rounded outline anteriorly (Figure
14.3). Posterior to the anterior opening, the canal
incises into the dorsal part of the centrum, so that it
becomes inverted teardrop-shaped in outline,
which is also the outline of the posterior opening. In
the posterior half of the centrum, the floor of the
neural canal is slightly convex. Anteriorly, the neu-
ral canal widens slightly both transversely and dor-
sally, so that the centroprezygapophyseal laminae
are slightly directed anterolaterally.
Robust transverse processes are present.
They are placed on the posterior half of the neural
arch, at the level of the roof of this structure (Figure
14.1). The transverse processes are directed later-
ally and slightly dorsally and posteriorly. The dorsal
inclination is approximately 25°-30° from the hori-
zontal. The processes are considerably longer (16
cm from neural arch to distal end) than the length
of the centrum and very slightly expand distally
(Figure 14.2). At the base, the anteroposterior
width of the processes is approximately 50 mm,
whereas the distal end has an estimated width of c.
65 mm. Rudimentary lateral laminae are present in
the proximal part of the transverse processes.
PALAEO-ELECTRONICA.ORG
25
However, these rudimentary laminae are less well-
developed than in abelisaurids (Rauhut et al.,
2003), and fossae between the laminae are only
indicated by very shallow depressions. Both ante-
rior and posterior centrodiapophyseal lamina are
represented by broad, rounded ridges that extend
from the dorsal end of the centrum towards the
ventral surface of the transverse processes. The
prezygadiapophyseal lamina is also represented
by a low ridge that extends from the lateral margin
of the prezygapophysis to the dorsal margin of the
base of the transverse process and thus defines
the dorsal rim of a shallow depression on the ante-
rior side of the thick base of the transverse pro-
cess. The base of the transverse process is thicker
dorsoventrally anteriorly than posteriorly, but
becomes rapidly more plate-like distally. The pro-
cesses are slightly twisted distally, so that the dor-
FIGURE 14. Anterior mid-caudal vertebra of Wiehenvenator albati in lateral (1; stereophotographs), dorsal (2), ante-
rior (3), and ventral (4) views. Abbreviations: nc, neural canal; ns, neural spine; pcd, pleurocentral depression; poz,
postzygapophysis, prz, prezygapophysis; r, ridge; tp, transverse process. Scale bar equals 100 mm.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
26
sal surface faces slightly anterodorsally towards
the distal end. On the dorsal surface of the neural
arch, a low, but well-defined ridge extends from the
base of the neural spine on either side anterolater-
ally towards the anterior margin of the base of the
transverse process (Figure 14.2). This ridge sepa-
rates a smaller, triangular depression anteriorly
from a larger posterior concavity on the posterior
part of the roof of the neural arch.
The prezygapophyses are placed on short
stalks so that they overhang the centrum for
approximately the entire length of their articular
surfaces. The prezygapophyses are short, diverge
very slightly anteriorly and are inclined medially at
an angle of approximately 55° from the horizontal.
The lateral side of the prezygapophyses bulges
slightly laterally at about the level of the dorsal
margin of the neural canal; this bulge becomes
lower anterodorsally. The articular surfaces are
anteroposteriorly short (c. 15 mm) and oval in out-
line, being wider (c. 19 mm) than long. They are
connected medially by a very stout intraprezyga-
pophyseal lamina, and there are low, but clearly
defined spinoprezygapophyseal laminae extending
from about the mid-width of the prezygapophyseal
stalks towards the base of the neural spine;
together these laminae define a narrow, triangular
prespinal fossa.
The postzygapophyses are poorly preserved.
They are placed below the base of the neural spine
and face lateroventrally at an angle of 45° from the
horizontal. The articular surface seems to have
been high oval in outline, but it is damaged posteri-
orly in the only preserved (left) postzygapophysis.
The postzygapophyses are connected to the trans-
verse processes by short, but stout postzygodia-
pophyseal laminae and to the neural spine by
likewise short, but well-defined spinopostzyga-
pophyseal laminae. The intrapostzygapophyseal
lamina is short and forms a rounded, V-shaped
edge some 5 mm above the neural canal; a hypo-
sphene is absent. The postzygapophyses and the
spinopostzygapophyseal laminae define an elon-
gate, narrow, but deep postspinal fossa.
The neural spine is placed on the posterior
two thirds of the neural arch. It is posteriorly
inclined at about 25°-30° from the vertical and very
high, reaching a height of c. 185 mm above the
roof of the neural arch. The spine is transversely
flat and anteroposteriorly wide at its base. It nar-
rows dorsally up to approximately its mid-height
and then very slightly expands again dorsally (Fig-
ure 14.3). Thus, its minimal anteroposterior width is
48 mm, whereas the dorsal width is 57 mm. In
anterior view, the basal part has a sharp anterior
margin, but this margin becomes wider and
rounded dorsally. Towards the dorsal end, the
spine slightly expands transversely to a maximal
transverse thickness of 16 mm. The dorsal end of
the spine is rounded transversely and anteroposte-
riorly straight over its anterior two thirds, whereas
the posterior third flexes posteroventrally. On the
posterior side of the spine, a ridge-like postspinal
lamina appears at about the mid-height of the
spine and continues ventrally between the spino-
postzygapophyseal laminae approximately to the
base of the neural spine.
In WMN P47417, the posterior articular sur-
face is slightly higher than wide, indicating that this
fragment might represent a slightly more anterior
caudal vertebra. The surface is slightly concave
dorsally, but becomes convex ventrally, where it
curves into the poorly defined chevron facets. The
ventral surface of the centrum is slightly convex
transversely, though less so than in WMN P27501,
and lacks any keel or furrow. The posterior end of
the lateral pleurocentral depression is preserved
on the lateral side of the vertebral fragment.
The other two more complete vertebrae (Fig-
ures 15, 16) represent more posterior mid-caudal
elements, but they do not seem to be consecutive
elements. The centra are smaller and relatively
TAB LE 2 . Measurements of caudal vertebrae of Wiehenvenator albati (in mm).
WMN P27501 WMN P27499 WMN P27500
Centrum length c. 110 114 11 4
Anterior centrum height 104 79 76
Anterior centrum width 113 c. 82 85
Posterior centrum height —80 72 +
Posterior centrum width —83 74 +
Minimal centrum width 50 c. 38 c. 35
Neural arch length 143 125 + 135
Total height c. 320 247 195 +
PALAEO-ELECTRONICA.ORG
27
more elongate than in the vertebra described
above. They are also strongly constricted. In the
more anterior element WMN P27499, the articular
surfaces are parallel (Figure 15), but in the more
posterior element WMN P27500, the posterior
articular surface is slightly angled posteroventrally
in respect to the anterior surface (Figure 16). Both
vertebrae are platycoelous, although the exact
morphology of the articular surfaces varies
between the elements and between the anterior
and posterior surface. Thus, in WMN P27499, the
anterior articular surface is flat to very slightly con-
vex, whereas the posterior surface is slightly con-
cave and the margins flex notably anteriorly. In
WMN P27500, the anterior articular surface is con-
cave with posterior flexed margins and the poste-
rior surface is slightly convex. In the latter element,
the posterior articular surface is also notably
smaller than the anterior surface, whereas they are
of subequal size in the more anterior vertebra.
Well-developed chevron facets are present in both
elements. However, whereas the facets are only
marked by the ventrally flexed posterior articular
end in the more posterior vertebra, the more ante-
rior element WMN P27499 shows two clearly
defined, concave facets posteroventrally. The ven-
tral sides of the centra are relatively narrower than
in WMN P27501, and two diverging ridges are
present on the posterior half of the ventral surface
(Figure 16.3). These ridges define a longitudinal
ventral depression, which is wider in WMN P27499
than in the more posterior element. In both verte-
brae, well-defined, elongate oval pleurocentral
depressions are present on the lateral side of the
centrum, just above its mid-height (Figures 15.2,
16.2). In contrast to the anterior mid-caudal, these
depressions are deepest in the middle part and
become gradually shallower towards either end,
and their dorsal and ventral margins are equally
strongly developed.
Of the neurocentral suture, only the posterior
ends of the pedicles of the neural arch are marked
as slightly offset bulges in the more anterior ele-
ment. The arches are low and have notably large
neural canals, which are very similar in shape and
development as in the vertebra described above.
As in the latter, the roof of the neural canal slightly
raises posteriorly. Both elements show strongly
developed transverse processes, which are still
placed on the posterior end of the neural arch at
the level of the roof of this structure. They show a
very similar dorsal and posterior inclination as in
the vertebra described above. In the better pre-
served element WMN P27499, the transverse pro-
cess has its anteroposteriorly narrowest part (34
mm) in its proximal third and then expands slightly
distally to a maximal anteroposterior width of 45
mm at about three-fourths of its length. At this
point, the posterior margin flexes notably anterolat-
erally. Unfortunately, the distalmost tip is not pre-
served, but if one extends the distalmost preserved
part of the posterior margin, it would have met the
gently posterolaterally curving anterior margin in a
pointed end. As in the more anterior vertebra, the
distal end of the process is slightly twisted to face
anterodorsally. The lateral lamination is more
weakly developed than in the vertebra described
above, but still present. An oblique ridge on the
dorsal surface of the base of the process, as
described for the more anterior element above, is
absent.
The prezygapophyes are missing in WMN
P27499, but present in the more posterior element
(Figure 16). They are very similar in shape and
development to the prezygapophyses of the ante-
rior element described above. However, there are
no clearly defined spinoprezygapophyseal lami-
nae and a prespinal fossa is absent.
The postzygapophyses are completely pre-
served in WMN P27499 (Figure 15). They are
placed posteroventrally to the base of the neural
spine, with the articular surfaces almost completely
overhanging the centrum. The articular surfaces
are high oval in outline and inclined to a similar
degree as those described above. In posterior
view, the postzygapophyses are relatively more
widely spaced than in the element described
above, and the intrapostzygapophyseal lamina is
straight, rather than ventrally pointed. The spino-
postzygapophyseal laminae are more weakly
developed and the postspinal fossa is marked, but
smaller than in the vertebra described above.
Both vertebrae show a small dorsal spur
some way anterior to the neural spine (Figures 15,
16). Whereas there is some uncertainty in the more
anterior vertebra in how far this spur might have
been connected to the base of the spine by a now
broken lamina, it is clearly separated in the more
posterior element, where it is a small, pointed pro-
cess (Figure 16.2), as in several other theropods,
such as Dubreuillosaurus (Allain, 2005), Allosaurus
(Madsen, 1976a), or Lourinhanosaurus (Mateus,
1998). The main neural spine is anteroposteriorly
short and placed on the posteriormost third of the
neural arch, with the posteriormost part of its base
being level or even slightly overhanging the poste-
rior end of the centrum. It is posterodorsally
inclined and remains of subequal anteroposterior
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
28
width over its entire height. The distal end is very
slightly expanded transversely in WMN P27499; in
the more posterior element, this part seems to be
incomplete. The dorsal margin is similar to the
more anterior element in WMN P27499. The dorsal
part of the neural spine has a sharp posterior, but
broad and rounded anterior margin, but the poste-
rior margin becomes broader and flattened ven-
trally. A very low postspinal ridge is present in the
ventral half of the spine.
Ribs. Several rib fragments and two more or less
complete dorsal ribs are present. An anterior tho-
racic rib (Figure 17.1) is 105 cm long along the
outer curve. The proximal two-thirds of the rib are
considerably curved, whereas the distal third is
almost straight, indicating a broad, oval ribcage for
Wiehenvenator. The proximal end is divided into a
long, medially directed capitulum and a much
shorter tuberculum, which are connected by a
robust bony lamina and thus not clearly separated,
although this might be partially due to damage of
the articular end. Proximally, the rib is thickened
both anteriorly and posteriorly on the lateral side,
resulting in a T-shaped cross-section of the rib.
This thickening disappears at approximately one-
third along the length of the element. Distal to this
point, the rib shaft gradually tapers, until it reaches
a thin, oval outline, which it retains for the distal
third of its length. The distal tip is broken, so it can-
not be said if a distal thickening, indicating the car-
tilaginous connection to a sternal rib, was present,
as it is found in other theropods.
A posterior, abdominal rib (Figure 17.2) is
strongly and gradually curved along its entire
length. The rib head has a long medial process for
the capitulum and a much shorter, strongly distally
displaced posterodorsal process for the tubercu-
lum. Both processes are connected by a thin bony
lamina. From the tuberculum, a posteriorly oriented
lamina extends along the posterolateral margin of
the rib shaft and becomes rapidly lower distally.
The rib shaft tapers gradually distally. Its anterior
side is flat, whereas the posterior side is broad and
convex transversely proximally (distal to the lamina
extending from the tuberculum described above),
but gets more narrow and thus more strongly con-
vex distally.
Gastralia. A robust, boomerang-shaped element
(WMN P27455) represents the gastral basket (Fig-
ure 17.3-5). In accordance with the situation in
other theropods (Chure, 2000; Allain and Chure,
2002), we interpret this element as the fused
FIGURE 15. Mid-caudal vertebra of Wiehenvenator albati in anterior (1) and lateral (2; stereophotographs) views.
Abbreviations as in Figure 14, and: as, anterior spur. Scale bar equals 100 mm.
PALAEO-ELECTRONICA.ORG
29
medial rods of a pair of posterior gastralia. The ele-
ment is dorsoventrally flattened, oval in cross-sec-
tion, and forms a wide U-shape in dorsal or ventral
view, with the angle between the two rami being
approximately 100°. The central part is slightly
curved ventrally in respect to the left and right
ramus and has a thickened anterior margin (Figure
17.5). Just lateral to the central fusion, a notable
longitudinal depression is present on the anterior
margin of the ventral side on either side (Figure
17.4) for the articulation with the lateral gastral ele-
ment (Chure, 2000; Allain and Chure, 2002). This
depression is open anteriorly, so that the anterior
margin of the lateral rami forms a sharp ridge,
whereas the posterior margin is more massive and
dorsoventrally rounded. The lateral rami become
more slender posterolaterally, but their tips are bro-
ken.
Forelimb. A single, damaged phalanx probably
represents the forelimb of Wiehenvenator (Figure
18). The proximal end of the element is largely
missing, so that only the central dorsal part of the
proximal articular surface is preserved, and the lat-
eral distal condyle is damaged. The element is
rather short and stout, with a length of c. 81 mm
and a minimal width in the shaft of 33 mm. This and
FIGURE 16. Posterior mid-caudal vertebra of Wiehenvenator albati in anterior (1), lateral (2), and ventral (3; stereo-
photographs) views. Abbreviations as in Figures 14 and 15, and: vg, ventral groove. Scale bar equals 100 mm.
RAUHUT, HÜBNER, & LANSER: GERMAN JURASSIC MEGALOSAURID
30
the fact that the proximal articular surface lacks a
median ridge indicate that it is probably the first
phalanx of digit III, most probably of the right
manus.
The proximal articular surface was obviously
notably concave transversely and extended slightly
more distally on the lateral side than on the medial
side. As noted above, it lacks a central ridge, indi-
cating that the metapodium proximal to it did not
have a ginglymodial distal articulation, which is the
case in metacarpal III in tetanurans. The shaft of
the bone is only slightly constricted (Figure 18.2),
its minimal width being only slightly less than the
width of the distal end (c. 38 mm). In lateral or
medial view (Figure 18.1), the bone gradually nar-
rows towards the distal ginglymus, indicating that
the damaged proximal part was dorsoventrally
high, as it is usual in the first phalanx of digit III in
tetanuran theropods (e.g., Madsen, 1976a; Currie
and Carpenter, 2000). A broad, but shallow exten-
sor groove is present on the dorsal side just proxi-
mal to the distal ginglymus. The distal articular end
is strongly ginglymoidal, with two well-rounded
condyles that are separated by a broad, U-shaped
furrow (Figure 18.2, 18.3). The articular surface
extends considerably further proximally on the ven-
FIGURE 17. Dorsal ribs and gastralia of Wiehenvenator albati. 1, thoracic rib. 2, abdominal rib. 3-5, fused posterior
medial gastralia in dorsal (3), ventral (4; stereophotographs), and anterior (5) views. Scale bar equals 100 mm.
PALAEO-ELECTRONICA.ORG
31
tral than on the dorsal side, as it is usual in manual
phalanges. Collateral ligament grooves are only
represented by shallow depressions that are
placed slightly dorsal from the midline in the gingly-
moidal arch (Figure 18.1). The medial groove is
better developed than the lateral one.
Hindlimb. The hindlimb of Wiehenvenator is repre-
sented by both fibulae, the right astragalus and a
partial right calcaneum.
Fibula. The better preserved left fibula (Figure 19)
has suffered from slight deformation, so that the
shaft is curved medially, and from minor erosion of
the distal end, but is otherwise complete. The bone
is notably robust for a theropod fibula, its length
being approximately 730 mm, the proximal antero-
posterior width 161 mm, and the anteroposterior
width at mid-shaft 56 mm. The anteroposterior
width of the less damaged distal end of the right
fibula is 101 mm, or 180% of mid-shaft width. The
proximal end is not only expanded anteroposteri-
orly in comparison to the shaft, but also trans-
versely: its maximal transverse width of 75 mm is
more than 250% of the minimal transverse width of
the shaft (c. 29 mm). In proximal view (Figure
19.2), the articular surface is comma-shaped,
becoming thinner posteriorly and with a medially
curved anteromedial edge, as in the fibula of an
indeterminate megalosauroid from the Late Juras-
sic of Tendaguru (Rauhut, 2011). The surface is
very slightly inclined proximomedially and slightly
concave anteroposteriorly over its anterior two-
thirds and convex over the posterior third. Although
the medial side of the proximal end is slightly con-
cave anteroposteriorly due to the medially curved
anteromedial edge, there is no medial depression
or fossa (Figure 19.3), in contrast to the situation in
many neotheropods, but as in Torvosaurus (Britt,
1991) and other megalosaurians (Benson, 2010a;
Carrano et al., 2012).
The lateral surface of the proximal end has a
slightly transversely convex anterior side that
curves into the almost flat central part of the lateral
side. Posteriorly, the lateral side becomes slightly
concave, and a short, longitudinal depression is
present posterolaterally some 50-60 mm below the
proximal end, as in Afrovenator and some other
theropods (see Benson 2010a, p. 918-919). A con-
siderably broader, but less deep and less well-
defined fossa is present on the anterior side of the
fibula in the same region (Figure 19.4); both
depressions fade out some 160-170 mm below the
proximal end, approximately at the level of the
beginning of the proximal expansion. Distal to
these depressions, the shaft of the fibula is strongly
anteroposteriorly convex. There is no marked
tubercle or ridge for the insertion of the M. iliofibu-
laris, as in Torvosaurus (Britt, 1991), but at approx-
imately the level where this insertion would have
been, the posterior two thirds of the lateral side of
the shaft become flattened, so that only the ante-
rior third retains an anteroposterior convexity. At
about the mid-length of the bone, the lateral side
becomes again gently convex anteroposteriorly,
but less so than proximal to the flattened part.
On the medial side there is a marked, rounded
tubercle at the anteroproximal edge (Figure 19.3).
Further distally, a broad, but low, roughly triangular
swelling is present anteriorly just proximal to the
level of the beginning of the proximal expansion.
Distal to this swelling, the posteromedial margin of