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Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian Theropods

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The Lourinhã Formation (Kimmeridgian-Tithonian) of Central West Portugal is well known for its diversified dinosaur fauna similar to that of the Morrison Formation of North America; both areas share dinosaur taxa including the top predator Torvosaurus, reported in Portugal. The material assigned to the Portuguese T. tanneri, consisting of a right maxilla and an incomplete caudal centrum, was briefly described in the literature and a thorough description of these bones is here given for the first time. A comparison with material referred to Torvosaurus tanneri allows us to highlight some important differences justifying the creation of a distinct Eastern species. Torvosaurus gurneyi n. sp. displays two autapomorphies among Megalosauroidea, a maxilla possessing fewer than eleven teeth and an interdental wall nearly coincidental with the lateral wall of the maxillary body. In addition, it differs from T. tanneri by a reduced number of maxillary teeth, the absence of interdental plates terminating ventrally by broad V-shaped points and falling short relative to the lateral maxillary wall, and the absence of a protuberant ridge on the anterior part of the medial shelf, posterior to the anteromedial process. T. gurneyi is the largest theropod from the Lourinhã Formation of Portugal and the largest land predator discovered in Europe hitherto. This taxon supports the mechanism of vicariance that occurred in the Iberian Meseta during the Late Jurassic when the proto-Atlantic was already well formed. A fragment of maxilla from the Lourinhã Formation referred to Torvosaurus sp. is ascribed to this new species, and several other bones, including a femur, a tibia and embryonic material all from the Kimmeridgian-Tithonian of Portugal, are tentatively assigned to T. gurneyi. A standard terminology and notation of the theropod maxilla is also proposed and a record of the Torvosaurus material from Portugal is given.
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Torvosaurus gurneyi
n. sp., the Largest Terrestrial
Predator from Europe, and a Proposed Terminology of
the Maxilla Anatomy in Nonavian Theropods
Christophe Hendrickx
1,2
*, Octa
´vio Mateus
1,2
1Departamento de Cie
ˆncias da Terra, Faculdade de Cie
ˆncias e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal, 2Museu da Lourinha
˜, Lourinha
˜, Portugal
Abstract
The Lourinha
˜Formation (Kimmeridgian-Tithonian) of Central West Portugal is well known for its diversified dinosaur fauna
similar to that of the Morrison Formation of North America; both areas share dinosaur taxa including the top predator
Torvosaurus, reported in Portugal. The material assigned to the Portuguese T. tanneri, consisting of a right maxilla and an
incomplete caudal centrum, was briefly described in the literature and a thorough description of these bones is here given
for the first time. A comparison with material referred to Torvosaurus tanneri allows us to highlight some important
differences justifying the creation of a distinct Eastern species. Torvosaurus gurneyi n. sp. displays two autapomorphies
among Megalosauroidea, a maxilla possessing fewer than eleven teeth and an interdental wall nearly coincidental with the
lateral wall of the maxillary body. In addition, it differs from T. tanneri by a reduced number of maxillary teeth, the absence
of interdental plates terminating ventrally by broad V-shaped points and falling short relative to the lateral maxillary wall,
and the absence of a protuberant ridge on the anterior part of the medial shelf, posterior to the anteromedial process. T.
gurneyi is the largest theropod from the Lourinha
˜Formation of Portugal and the largest land predator discovered in Europe
hitherto. This taxon supports the mechanism of vicariance that occurred in the Iberian Meseta during the Late Jurassic when
the proto-Atlantic was already well formed. A fragment of maxilla from the Lourinha
˜Formation referred to Torvosaurus sp. is
ascribed to this new species, and several other bones, including a femur, a tibia and embryonic material all from the
Kimmeridgian-Tithonian of Portugal, are tentatively assigned to T. gurneyi. A standard terminology and notation of the
theropod maxilla is also proposed and a record of the Torvosaurus material from Portugal is given.
Citation: Hendrickx C, Mateus O (2014) Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla
Anatomy in Nonavian Theropods. PLoS ONE 9(3): e88905. doi:10.1371/journal.pone.0088905
Editor: Alistair Robert Evans, Monash University, Australia
Received July 25, 2013; Accepted January 7, 2014; Published March 5, 2014
Copyright: ß2014 Hendrickx, Mateus. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This research was supported by the Fundac¸a
˜o para a Cie
ˆncia e a Tecnologia (FCT) scholarship SFRH/BD/62979/2009 (Ministe
´rio da Cie
ˆncia, Tecnologia e
Ensino superior, Portugal) and the Dinoeggs Project (PTDC/BIA-EVF/113222/2009) financed by FCT/MEC (PIDDAC). The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
* E-mail: christophe.hendrickx@hotmail.com
Introduction
The Upper Jurassic beds of central Portugal have yielded
numerous dinosaur taxa representing one of the richest European
faunas of dinosaurs from the Mesozoic, and certainly the most
diverse one from the Late Jurassic of Europe. Members of all
major clades of dinosaurs other than marginocephalians are
represented, and theropods are by far the most diversified group of
the clade Dinosauria [1–3]. Hitherto, tracks, eggs, teeth and bone
material (including embryos and hatchlings) discovered in the
Alcobac¸a Formation (Kimmeridgian) of the Guimarota mine [1]
and Lourinha˜ Formation (Kimmeridgian-Tithonian) of the
Lourinha˜ region [3,4] have been assigned to at least ten theropod
taxa belonging to the clade of Ceratosauridae [4,5], Abelisauridae
[6], Megalosauridae [4,6–9], Allosauroidea [4,10–15], Tyranno-
sauroidea [16], Compsognathidae [17], Avialae [18,19], and some
uncertain systematic theropod clades [6,17,20].
The Alcobac¸a and Lourinha˜ Formation are comparable to the
contemporaneous Morrison Formation of Northern America both
paleoenvironmentally and sedimentologically [3]. Most of non-
coelurosaurian taxa (i.e., Allosaurus,Ceratosaurus and Torvosaurus)
were present on both continents, indicating some faunal exchanges
between the Iberian Meseta and North America in the Late
Jurassic, although an intercontinental sea was already separating
them [3,21]. Mateus et al. [21] proposed that during the
Callovian/Oxfordian transition, there were temporary land
bridges that allowed terrestrial faunal exchange between North
America and the Iberian Meseta. The high diversity of theropods
in the Late Jurassic of Laurasia, represented by small, medium-
sized and large individuals, indicates important niche partitioning
between these carnivorous dinosaurs. The top predators at the
acme of the food chain were represented by three large theropods,
Lourinhanosaurus,Ceratosaurus and Allosaurus, and a very large form,
Torvosaurus, functionally and ecologically similar to the super-
predators Carcharodontosaurus and Tyrannosaurus from the Late
Cretaceous of Africa and North America, respectively.
Torvosaurus has been reported several times in the Upper Jurassic
of central Portugal in the locality of Casal do Bicho (Alcobac¸a),
Quinta do Gradil (Cadaval), Praia da Corva (Porto Novo) and
Praia da Vermelha (Lourinha˜). This taxon is represented by a
large tibia (ML 430) and a left maxilla (ML 1100) briefly described
by Mateus & Antunes [7] and Mateus et al. [4], respectively, as
well as a distal end of a femur (ML 632), a caudal vertebra (ML
1100) and a fragment of an unidentified limb bone (ML 1100)
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reported by Mateus et al. [4]. Malafaia et al. [8] published a
fragment of right maxilla (ALT–SHN.116) whereas a mesialmost
tooth (ML 962) was described by Hendrickx & Mateus [6]. Finally,
embryonic remains (ML1188) discovered among a clutch of eggs
have recently been reported by Arau´jo et al. [9]. These elements
were all ascribed to the genus Torvosaurus or the species Torvosaurus
tanneri although differences have been noted between the material
from Portugal and the United States [4].
The present work aims to propose a standard terminology of the
maxilla for nonavian theropods as well as to provide a thorough
description of the material ML 1100 assigned to the species
Torvosaurus tanneri [4]. Attribution to this taxon will be discussed
after a detailed comparison with other megalosaurid material. A
review of the Torvosaurus material from Portugal will finally be
given.
Materials and Methods
Institutional Abbreviations
See Text S1.
Nomenclatural Act
The electronic edition of this article conforms to the requirements
of the amended International Code of Zoological Nomenclature,
and hence the new names contained herein are available under that
Code from the electronic edition of this article. This published work
and the nomenclatural acts it contains have been registered in
ZooBank, the online registration system for the ICZN. The
ZooBank LSIDs (Life Science Identifiers) can be resolved and the
associated information viewed through any standard web browser
by appending the LSID to the prefix ‘‘http://zoobank.org/’’. The
LSID for this publication is: urn:lsid:zoobank.org:pub:4BD514CF-
2AF8-401E-AC21-CB703D08089B. The LSID for this publication
is: urn:lsid:zoobank.org:act:189C1060-7887-4837-9E30-870079E2
B2B9. The electronic edition of this work was published in a journal
with an ISSN, and has been archived and is available from the
following digital repositories: PubMed Central (http://www.ncbi.
nlm.nih.gov/pmc) and LOCKSS (http://www.lockss.org).
Proposed Terminology of the Maxilla Anatomy in
Nonavian Theropods
The maxilla is a cranial bone displaying an important
morphological variability among nonavian theropods (e.g.,
[9]:note 3; [22]:fig. 3; [23]:fig. 4.5). Such morphological variation
shows the great taxonomical utility and systematic potential of the
maxilla in this clade of dinosaurs. As this bone provides far more
information than many other parts of the skeleton, and the
diagnostic value of the maxilla is significant, particular attention
should be accorded to the description of this bone in the literature
on nonavian theropod anatomy. Nevertheless, the terminology
and abbreviations of the maxilla anatomy have been inconsistent
in nonavian theropods. Several different anatomical terms for the
same maxilla sub-entity have been often used, as in some examples
given below. An attempt of a standard terminology for the maxilla
was already proposed by Witmer [24] who, however, mostly
concentrated on the maxillary sinuses and did not provide a
terminology for the maxillary ramus, processes and articulations.
The present paper aims to propose a standardization of the
anatomical terms for each of the maxilla sub-units (Figs. 1–3),
mostly selected by their relevance, significance and importance in
the theropod literature, in order to facilitate future description of
this bone. The anatomical terms were grouped into nine sections,
and each term is associated with a three to four letters abbreviation
and followed by a definition. The nomenclature for pneumatic
recesses and openings mostly follows the terminology given by
Witmer [24] and only differs for a few terms. For clarity reasons,
the internal antorbital fenestra, caudal fenestra of the maxillary
antrum, and fenestra communicans of Witmer [24] are here
referred to as the antorbital fenestra, posteromedial maxillary
fenestra, and anteromedial maxillary fenestra, respectively. Gold
et al. [25] noticed some confusion with the term ‘‘recess’’ in the
literature and preferred using ‘‘promaxillary sinus’’ instead of
‘‘promaxillary recess’’. Nevertheless, only one maxillary sinus may
have invaded both maxillary antrum and promaxillary recess [26]
and we therefore favoured Witmer’s terminology. The presence of
unnamed fossae/fenestrae within the antorbital fossa in some
allosauroids (Fig. 1), tyrannosaurids (Figs. 2–3) and oviraptorosaurs
have lead us to propose additional terms for several maxillary sub-
units, namely: pneumatic fenestra, ventral maxillary fenestra,
medial maxillary fenestra, dorsomedial maxillary fenestra, post-
maxillary fenestra, anteromedial and posteromedial maxillary
recesses, postmaxillary and preantral struts. Likewise, we are
proposing the terms ‘‘interdental wall’’ for the continuous lamina
formed by the fusion of interdental plates.
Bodies, Rami and Processes
The anatomical term ‘‘ramus’’ was favoured over ‘‘process’’ for
the large projecting parts of the maxilla (e.g., ascending ramus,
jugal ramus, anterior ramus), the term ‘‘process’’ being referred to
a smaller projection of bone (e.g., anteromedial process).
Maxillary body (mbo). Ventral part of the maxilla that
excludes the ascending ramus (Fig. 2A). The delimitation of the
maxillary body from the ascending ramus is somewhat subjective.
Usually, these two units are virtually delimited by a constriction
formed by the antorbital fenestra and a concave step on the
anterodorsal margin of the maxilla. However, the anterior margin
of the maxillary body and the ascending ramus can be confluent.
In that case, the maxillary body and the ascending ramus should
be delimited by a virtual line starting from the apex of the
curvature of the antorbital fenestra (which is not always the
anteriormost point of the antorbital fenestra) and extending in
parallel to the main axis of the ventral margin of the maxilla. The
maxillary body, as used by several authors (e.g., [4,27–31]), is also
termed the main body (e.g., [32–37]). It includes two main
anatomical units: the anterior body and the jugal ramus.
Anterior body (anb). Anterior part of the maxillary body
that extends from the premaxilla contact to the anteriormost point
of the antorbital fenestra (Fig. 2A). The anterior body, corre-
sponding to the ventral ramus of the nasal process of [38], includes
both the preantorbital body and anterior ramus.
Preantorbital body (pab). Anterior part of the maxillary
body that extends from the premaxilla contact to the anteriormost
point of the antorbital fossa (Fig. 2B). The preantorbital body, also
known as the preantorbital process [29], is part of the anterior
body.
Anterior ramus (anr). Anterior projection of the maxillary
body that extends from the premaxilla contact to a concave step
on the anterodorsal margin of the maxilla that corresponds to the
boundary between the maxillary body and the ascending ramus
(Fig. 1A). The anterior ramus is considered to be absent when the
anterodorsal margin of the maxillary body and the anterior
margin of the ascending ramus are confluent. The anterior ramus,
also called the rostral ramus [39] or anterior process (e.g., [37–42])
is part of the anterior body. It can also be part of the preantorbital
body, or confluent with it when the concave step on the
anterodorsal margin of the maxilla and the anteriormost point of
the antorbital fossa are at the same level.
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Ascending ramus (asr). Dorsal part of the maxilla that
excludes the maxillary body and contacts the nasal anteriorly and
the lacrimal dorsally (Fig. 2A). Also known as the ascending
process (e.g., [29,36,43]), posterodorsal process (e.g., [28,44,45]),
nasal process (e.g., [27,46,47]), lacrimal process (e.g., [34]) and
dorsal/ascending ramus of the nasal process [38].
Jugal ramus (jur). Posterior part of the maxillary body
situated below the antorbital fenestra (Fig. 2A). The jugal ramus,
as used by several authors (e.g., [33,34]), is also referred as the
jugal process (e.g., [40,41,48]), posterior process (e.g., [31]),
posterior ramus (e.g., [49–51]), subantorbital ramus (e.g., [29]),
and subantorbital process (e.g., [38]).
Anteromedial process (amp). Projection of bone on the
medial surface of the maxillary body, on the anterodorsal corner of
the anterior maxillary body, protruding anteriorly or anteroven-
trally to contact the premaxilla anteriorly, and the vomer and the
opposite maxilla medially (Figs. 1C, 2C). The anteromedial
process is also known as the rostromedial process (e.g., [25,33])
and palatal process (e.g., [48,52–54]).
Walls, Shelves and Ridges
Lateral wall (law). Bone surface laterally situated, covering
the whole surface of the maxilla, from the ventral margin ventrally
to the posterior tip of the ascending ramus dorsally, and bounding
laterally the maxillary alveoli and different diverticula located
within the maxilla (Fig. 2C). The lateral wall (lamina lateralis sensu
[24]), as used by [36] and [41], is also known as the labial wall (e.g.
[31,55]) and lateral lamina (e.g., [31,38,41]).
Antorbital ridge (aor). Low crest on the lateral surface of
the maxilla, extending from the maxillary body to the ascending
ramus, and bordering the lateral antorbital fossa anteriorly and
ventrally (Fig. 1A).
Vestibular bulla (veb). Convexity located on the antero-
dorsal margin of the maxillary body and the floor of the nasal
Figure 1. Proposed terminology and annotation of the nonavian theropod maxilla. Right maxilla of Allosaurus fragilis (USNM 8335) in A,
lateral; B, anterior; C, medial and D, posterior views, with details of E, promaxillary recess and maxillary antrum in medial view; and F, ascending
ramus and dorsal margin of vestibular bulla in dorsal view. Abbreviations: ammf, anteromedial maxillary fenestra; amp, anteromedial process; anr,
anterior ramus; aor, antorbital ridge; asr, ascending ramus; idw, interdental wall; ifs, interfenestral strut; juc, jugal contact; lac, lacrimal contact;
laof, lateral antorbital fossa; law, lateral wall; maf, maxillary alveolar foramina; man, maxillary antrum; maof, medial antorbital fossa; mbo, maxillary
body; mcf, maxillary circumfenestra foramina; mes, medial shelf; mew, medial wall; mfe, maxillary fenestra; mfo, maxillary fossa; mmf, medial
maxillary foramina; mx1, first maxillary tooth; nac, nasal contact; nuf, nutrient foramina; nug, nutrient groove; pac, palatine contact; pmc,
premaxillary contact; pmmf, posteromedial maxillary fenestra; pmr, promaxillary recess; pne, pneumatic excavation; poas, postantral strut; pras,
preantral strut; snf, subnarial foramen; suas, suprantral strut; veb, vestibular bulla. Scale bars = 5 cm.
doi:10.1371/journal.pone.0088905.g001
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vestibule, and corresponding to an inflated, thin-walled bony
bubble of the anterodorsal portion of the promaxillary recess
[24,53] (Fig. 1A–C). The vestibular bulla (bulla vestibularis sensu
[24]) can be perforated and opened to the external naris through a
small foramen (the anterodorsal foramen). A vestibular bulla is
noticeable in many non-avian theropods such as Marshosaurus,
Allosaurus,Sinraptor [24], Acrocanthosaurus [49], Proceratosaurus [29],
Albertosaurus [48], Appalachiosaurus ([56]:fig. 6A), Byronosaurus [57]
and Troodon ([58]:fig. 2.1).
Medial wall (mew). Bone surface medially situated, covering
the surface of the maxilla dorsal to the nutrient groove (i.e., medial
surface of the maxilla excluding the interdental plates), and
bounding medially the different diverticula situated within the
maxilla (Figs. 1C, 2C). The surface of the medial wall can be
fenestrated at the level of the ascending ramus, and the maxillary
antrum and promaxillary recess. Likewise, the medial wall ventral
to the medial shelf can be undulated for receiving the dentary teeth
if they are abutting against this surface when the jaws are closed
(e.g., Torvosaurus,Carcharodontosaurus,Tyrannosaurus). The medial
wall is also known as the medial lamina for some authors (e.g.,
[38,50,59]).
Medial shelf (mes). Anterodorsally elongated ridge on the
medial surface of the maxillary body, extending from the
anteromedial process to the jugal ramus (and in some cases the
jugal contact), and protruding medially to contact the opposite
maxilla, palatine and, in some cases, vomer (Figs. 1C, 2C). Also
known as the lingual bar (e.g., [41,47]) or palatal shelf (e.g.,
[32,34,60]).
Lingual wall (liw). Bone surface medially situated, covering
the surface of the maxilla ventral to the nutrient groove and
bounding each maxillary interdental plates medially, anteriorly
and posteriorly (Figs. 1C, 2C). The lingual wall, as used by [31]
and [36], is either formed by a row of separated interdental plates
or a continuous interdental wall.
Interdental plate (idp). Flat bony structure medial to the
dental tooth row and attached to the lateral wall of the maxilla by
a perpendicular and mediolaterally oriented lamina that separates
each individual tooth socket (Fig. 2C). The interdental plates, also
known as paradental plates [52,61,62], vary in size and
morphologies and can either be separated by an interdental gap,
or completely fused.
Interdental wall (idw). Continuous medial wall ventral to
the nutrient groove and formed by the fusion of interdental plates
(Fig. 1C). The interdental wall is also known as the paradental
lamina [29] or paradental shelf [63], and the array of unfused
interdental plates present in many theropods does not constitute
an interdental wall.
Alveoli, Teeth and Margins
Maxillary alveoli (mal). Tooth sockets located on the
ventral margin of the maxilla (Fig. 3C2). They can be well-
separated by the interdental plates, or merged to form an open
groove like in troodontids.
Maxillary teeth (mx). Teeth of the maxilla located within
the alveoli (Figs. 1A–B, 2A). Due to the multiple generations of
replacement teeth in the alveoli at one time, maxillary teeth, like
those of the premaxilla and dentary, can be unerupted, semi-
erupted and fully erupted.
Tooth root bulge (trb). Crenulated margin of the ante-
rodorsal rim of the jugal ramus resulting from the protrusion of the
Figure 2. Proposed terminology and annotation of the
nonavian theropod maxilla. Left maxillae of Tyrannosaurus rex in
A–B, lateral view (CMNH 9380, reversed); and C, medial view (BHI 3033;
modified from [32]). Abbreviations: ammf, anteromedial maxillary
fenestra; amp, anteromedial process; anb, anterior body; aofe,
antorbital fenestra; asr, ascending ramus; ear, epiantral recess; idg,
interdental gap; idp, interdental plate; ifs, interfenestral strut; juc, jugal
contact; jur, jugal ramus; lac, lacrimal contact; laof, lateral antorbital
fossa; law, lateral wall; maf, maxillary alveolar foramina; man, maxillary
antrum; mbo, maxillary body; mcf, maxillary circumfenestra foramina;
mes, medial shelf; mew, medial wall; mfe, maxillary fenestra; mx9,
ninth maxillary tooth; nac, nasal contact; nuf, nutrient foramina; nug,
nutrient groove; pab, preantorbital body; pac, palatine contact; pmc,
premaxillary contact; pmf, promaxillary fenestra; pmmf, posteromedial
maxillary fenestra; pmr, promaxillary recess; pne, pneumatic excava-
tion; poas, postantral strut; pras, preantral strut; prms, promaxillary
strut; snf, subnarial foramen. Scale bars = 5 cm.
doi:10.1371/journal.pone.0088905.g002
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tooth roots into the antorbital fenestra (Fig. 3B1). A tooth root
bulge (eminentia radices dentis sensu [24]) exists in some basal
averostrans such as Ceratosaurus (USNM 4735; UMNH VP 5278;
MWC 1.1) and Marshosaurus (UMNH VP 7824, 7825).
Alveolar margin (alm). Ventral border of the maxilla along
the maxillary tooth row (i.e., distance from the anterior point of
the anteriormost maxillary alveolus to the posterior point of the
posteriormost maxillary alveolus; Fig. 3D).
Ventral margin (vem). Ventral border of the lateral wall of
the maxilla, from the anteroventral corner of the anterior body, to
the posteroventral extremity of the jugal ramus (Fig. 3D). The
ventral margins of the lateral and medial walls do not always
coincide, but the lateral margin extends more ventrally in the large
majority of theropods (pers. obs.).
Figure 3. Proposed terminology and annotation of the nonavian theropod maxilla. A, Right maxilla of Allosaurus fragilis (AMNH 600) in
posteromedial view; B, lateral antorbital fossae of Ceratosaurus in lateral view; B1, right maxilla of Ceratosaurus magnicornis (MWC 1) and; B2, left
maxilla of Ceratosaurus dentisulcatus (UMNH VP 5278; courtesy of Roger Benson); C, left maxilla of Tyrannosaurus rex (CMNH 9380) in posterodorsal
(C1) and dorsal (C2) views; D, left maxilla of Tarbosaurus baatar (ZPAL MgD-I/4; courtesy of Stephen Brusatte) in lateral view; E, right maxilla of
Duriavenator hesperis (BMNH R332) in dorsomedial view; and F, left maxilla of Piatnitzkysaurus floresi (PVL 4073) in dorsomedial view (courtesy of
Martin Ezcurra). Abbreviations: amf, accessory maxillary fenestra; ammf, anteromedial maxillary fenestra; ampr anteromedial pneumatic recess; iar,
interalveolar recess; mal, maxillary alveoli; mes, medial shelf; mfe, maxillary fenestra; mfo, maxillary fossa; pmf, promaxillary fenestra; pmmf,
posteromedial maxillary fenestra; pmr, promaxillary recess; pne, pneumatic recess; poas, postantral strut; pras, preantral strut; ptmf, postmaxillary
fenestra; ptms, postmaxillary strut; trb, tooth root bulge; vmpr, ventromedial pneumatic recess. Scale bars = 5 cm.
doi:10.1371/journal.pone.0088905.g003
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Maxillary Contacts
Premaxillary contact (pmc). Articular surface on the
anterior margin of the maxillary body and receiving the
premaxilla (Figs. 1B, 2C).
Jugal contact (juc). Articular surface on the posterolateral or
ventral surface of the jugal ramus of the maxilla and receiving the
jugal bone (Figs. 1A, 2B).
Palatine contact (pac). Articular surface along the medial
shelf or the medial wall of the maxilla and receiving the palatine
(Figs. 1C, 2C).
Nasal contact (nac). Articular surface on the dorsal surface
of the maxillary body and the anterior, dorsal, lateral and medial
surface of the ascending ramus and receiving the nasal (Figs. 1C,
E, 2C).
Lacrimal contact (lac). Articular surface on the laterodorsal
or dorsomedial surface of the ascending ramus and receiving the
lacrimal (Figs. 1A, 2B).
Fossae and Pneumatic Openings
Antorbital fossa (aofo). Large depression surrounding and
including the antorbital fenestra on the lateral and, in some cases,
the medial surface of the maxilla. Its anterior, ventral and dorsal
extensions are highly variable among theropods, covering most of
the maxillary body in some basal tetanurans or reduced to a very
short depression adjacent to the antorbital fenestra in some
abelisaurids.
Lateral antorbital fossa (laof). Depression surrounding the
antorbital fenestra on the lateral surface of the maxilla (Figs. 1A,
2B). A peripheral rim and, in some case, a raised antorbital ridge
along the lateral wall of the maxilla delimit the lateral antorbital
fossa. The lateral antorbital fossa, corresponding to the external
antorbital fenestra of [24], typically hosts the accessory antorbital
fossae and fenestrae of the maxilla (e.g., promaxillary, maxillary,
postmaxillary and pneumatic fenestrae and fossae) and pneumatic
excavations. The lateral antorbital fossa is continuous with the
antorbital fossa of the nasal, lacrimal and jugal in most of
theropods.
Medial antorbital fossa (maof). Depression surrounding
the antorbital fenestra on the medial surface of the maxilla
(Fig. 1C). The medial antorbital fossa is usually bordered by a
peripheral step running from the maxillary body to the ascending
ramus. It typically hosts some opening such as the posteromedial
maxillary fenestra, several ventral pneumatopores and neurovas-
cular openings. The medial antorbital fossa, which corresponds to
the pneumatic fossa of [41], is continuous with the antorbital fossa
of the palatine in most of theropods.
Maxillary fossa (mfo). Depression variable in size and
shape, homologous to the maxillary fenestra but bounded medially
by a thick medial wall (Fig. 3B1–B2). The maxillary fossa, also
known as the preantorbital fossa [43] and maxillary fenestra (e.g.,
[40,41,46,62]), differs from the maxillary fenestra by being a
shallow or deep and well-delimited depression that does not lead to
a maxillary antrum. A maxillary fossa is present in coelophysoids
(e.g., Dracovenator,Zupaysaurus,‘Syntarsus’), Ceratosaurus, and non-
spinosaurid megalosauroids (e.g., Marshosaurus,Afrovenator,Dubreuil-
losaurus,Eustreptospondylus,Megalosaurus,Torvosaurus). Given its size,
shape and comparable location to this of coelophysoids and
megalosauroids, the large depression located in the anterior corner
of the lateral antorbital fossa is interpreted as the maxillary fossa in
Ceratosaurus,Limusaurus,Noasaurus,Masiakasaurus and Monolopho-
saurus.
Promaxillary fossa (pmfo). Depression variable in size and
shape, homologous to the promaxillary fenestra but bounded
medially by a thick medial wall. As for the maxillary fossa, the
promaxillary fossa differs from the promaxillary fenestra in not
leading to a promaxillary recess. A promaxillary fossa occurs in
coelophysoids such as Coelophysis,Dracovenator and Zupaysaurus.
Pneumatic excavation (pne). Fossa variable in size and
shape but usually being a large ovoid or lanceolate depression
located within the lateral or medial surface of the ascending ramus
and bounded by the medial wall medially or lateral wall laterally
(Figs. 1A, C, 2C, 3B1–B2). The pneumatic excavation (excavation
pneumatica sensu [24]) can be fenestrated, as in Eocarcharia [50],
and is generally located at mid-height of the ascending ramus,
within the antorbital fossa. In some cases, it also communicates
with other maxillary recesses situated more ventrally [24]. A
pneumatic excavation exits in many theropods such as Coelophysis
[42], Ceratosaurus (USNM 4735; MWC 1.1; UMNH VP 5278;
Fig. 3B), Sinosaurus (KMV 8701), Sinraptor (IVPP 10600),
Yangchuanosaurus (CV 00215, 00216), Allosaurus (UMNH VP
5393, 9168; USNM 8335), Alioramus (IGM 100-1844) and
Bambiraptor (AMNH 30556).
Medial pneumatic complex (mpc). Set of pneumatic
excavations located within the anterior corner and dorsomedial
surface of the medial antorbital fossa, and penetrating the
ascending and jugal rami [41]. The medial pneumatic complex
includes both anteromedial and posteromedial pneumatic recesses.
Anteromedial pneumatic recess (ampr). Pneumatic exca-
vation located within the anterior corner of the medial antorbital
fossa and penetrating the ascending process of the maxilla (Fig. 3E–
F). The anteromedial pneumatic recess, also known as the
pneumatic excavation [40,41], is homologous to the posteromedial
maxillary fenestra but differs from the latter by not leading to a
maxillary antrum. An anteromedial pneumatic recess can be
observed in many megalosauroids such as Piatnitzkysaurus (PVL
4073), Marshosaurus (UMNH 7825), Eustreptospondylus (OUMNH
J.13558), Afrovenator (MNN UBA1), Megalosaurus (OUMNH
J.13506) and Duriavenator (BMNH R.332).
Ventromedial pneumatic recess (vmpr). Pneumatic exca-
vation located within the anteroventral corner or ventral part of
the medial antorbital fossa, on the dorsomedial surface of the jugal
ramus, and penetrating the jugal ramus of the maxilla (Fig. 3E–F;
Fig. 3C2). The ventromedial pneumatic recess, also known as the
pneumatic excavation [40,41], is usually associated with an
anteromedial pneumatic recess situated anterodorsally to it. A
ventromedial pneumatic recess can be observed in several
megalosauroids such as Piatnitzkysaurus (PVL 4073) and Duriavenator
(BMNH R.332), and the tyrannosaurid Tyrannosaurus (CMNH
9380).
Fenestrae
Antorbital fenestra (aofe). Large opening posterior to the
external naris and anterior to the orbital fenestra, and mostly
delimited by the maxilla, jugal and lacrimal (Fig. 2B). Also known
as the internal antorbital fenestra (fenestra antorbitalis interna sensu
[24]), the external antorbital fenestra (fenestra antorbitalis externa
sensu [24]) being delimited by the peripheral rim of the antorbital
fossa [24].
Accessory antorbital fenestra (aafe). Opening anterior to
the antorbital fenestra within the anterior corner of the lateral
antorbital fossa. Accessory antorbital fenestrae encompasses the
promaxillary, maxillary, postmaxillary and pneumatic fenestrae.
The accessory antorbital fenestra, also known as the accessory
antorbital opening (e.g., [31]), is usually employed when it cannot
be referred with certainty to the promaxillary or maxillary fenestra
(e.g., [38,50,60,64]). It also refers to the maxillary fenestra [65].
Maxillary fenestra (mfe). Aperture variable in size and
shape, but usually being a large, sub-circular opening, leading
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medially to the maxillary antrum or perforating the medial wall of
the maxilla [24] (Figs. 1A, E, 2B, C, 3D). The maxillary fenestra
[46,66] (fenestra maxillaris sensu [24]), also known as the accessory
foramen, second antorbital fenestra [67], second antiorbital
fenestra [68], subsidiary antorbital fenestra [69,70], and accessory
antorbital fenestra (e.g., [65]), is situated within the anterior corner
of the lateral antorbital fossa, at the base of the ascending ramus,
posterior (and sometimes dorsal) to the promaxillary fenestra and
anterior to the antorbital fenestra and the postmaxillary fenestra.
Its presence has been noted in most nonavian neotetanurans (e.g.,
allosauroids, tyrannosauroids, compsognathids, ornithomimo-
saurs, therizinosauroids, oviraptorosaurs, deinonychosaurs), with
perhaps the exception of Erlikosaurus [71].
Promaxillary fenestra (pmf). Aperture variable in size and
shape, but usually being a small slit-like opening, leading medially
to the promaxillary recess, or in some cases, perforating the medial
wall of the maxilla [24] (Figs. 1C, E, 2B, 3B1–C1). The
promaxillary fenestra [72], (fenestra promaxillaris sensu [24]), also
known as the promaxillary foramen (e.g., [29,49,59]), premaxillary
fenestra (e.g. [30,73,74]) and tertiary antorbital fenestra (e.g.,
[38,65]), is situated within the anterior corner of the lateral
antorbital fossa, at the base of the ascending ramus and anterior to
the maxillary fenestra. It is not always visible in lateral view, being
concealed by the lateral wall of the maxilla and stuck up in the
anterior corner of the lateral antorbital fossa. A slit-shaped
promaxillary fenestra exists in many theropods such as Herrer-
asaurus,Eodromaeus,Dilophosaurus, Abelisauroidea, Megalosauroi-
dea, Allosauroidea (e.g., Allosaurus,Neovenator), Tyrannosauroidea
and most Maniraptoriformes, whereas a large discrete promax-
illary fenestra can be observed in basal averostrans (e.g.,
Ceratosaurus,Sinosaurus), some allosauroids (e.g., Sinraptor,Yangchua-
nosaurus,Acrocanthosaurus,Eocarcharia), compsognathids (e.g., Comp-
sognathus,Scipionyx) and possibly in oviraptorosaurs (e.g., Incisivor-
osaurus,Citipati,Khaan, see [75] for discussion on the accessory
antorbital openings in Oviraptorosauria). Carcharodontosaurinae,
some dromaeosaurids, and most derived Troodontidae seem to be
devoid of a promaxillary fenestra ([38], pers. obs.), the maxillary
and promaxillary fenestrae having most likely merged in
Carcharodontosaurinae.
Pneumatic fenestra (pnf). Aperture variable in size and
shape, situated within the pneumatic excavation, and leading
medially to a deep pneumatic recess within the ascending process,
or in some cases, perforating the medial wall of the maxilla. The
pneumatic fenestra, also known as the accessory fenestra [50], is
present in the sinraptorid Sinraptor [24,45], the basal carchar-
odontosaurids Acrocanthosaurus (right maxilla, [49]) and Eocarcharia
[50], and the dromaeosaurid Bambiraptor (AMNH 30556).
Postmaxillary fenestra (ptmf). Small sub-circular aperture
situated within the antorbital fossa, between the maxillary fenestra
and the antorbital fenestra (Fig. 3D). According to Larson [76], the
postmaxillary fenestra, also known as the accessory maxillary
fenestra [77] (small foramen along the ventral margin of the
antorbital fossa of [78]), may result from depositional weathering
or breakage. Its presence in many specimens of Tyrannosaurinae
such as Tyrannosaurus (e.g., BHI 3033; LACM 23844; UCMP
118742), Tarbosaurus (ZPAL MgD-I/4) and Zhuchengtyrannus
([77]:fig. 2C–D) however makes this hypothesis unlikely. One or
two small openings also exists within the antorbital fossa, between
a large promaxillary fenestra (interpreted as such by [75]) and the
antorbital fenestra, in the maxilla of the oviraptorid Khaan ([75],
pers. obs.). Although the postmaxillary fenestra and these
‘‘postmaxillary’’ foramina occupy the same location within the
antorbital fossa, they are not homologous.
Ventral maxillary fenestra (vmf). Anteroposterioly elon-
gated aperture situated on the antorbital body, beneath the lateral
antorbital fossa. One or several ventral maxillary fenestrae have
been noticed in several Oviraptoridae such as Citipati (IGM 100-
978), Khaan (IGM 100-1127), Conchoraptor ([79]: fig. 8.1G) and an
unpublished oviraptorid (MPC-D 100/4; [79]:fig. 8.1GE). These
openings, referred to as the ‘‘additional accessory foramen’’ by
[75], may not be pneumatic in nature, and may represent
maxillary neurovascular foramina that are greatly enlarged,
feeding the rhamphotheca and soft tissues of the jaw margin in
oviraptorids (J. Headden pers. comm.). The ventral maxillary
fenestrae may therefore be homologous to the row of maxillary
circumfenestra foramina existing in other theropods. These large
apertures do not seem to exist in any other nonavian theropod
clade.
Posteromedial maxillary fenestra (pmmf). Ventrodorsally
elongated aperture delimited by the lateral wall of the maxilla
laterally and the medial wall medially (Figs. 1C–D, 2C, 3A,
C1–C2). The posteromedial maxillary fenestra, corresponding
to the caudal fenestra of the maxillary antrum of [24] and
used as such by several authors (e.g., [55–57]), is situated
within the anterior corner of the medial antorbital fenestra
and leads to the maxillary antrum. A posteromedial
maxillary fenestra exists in spinosaurids (e.g., Suchomimus,Spino-
saurus), allosauroids (Sinraptor,Allosaurus) and tyrannosauroids (e.g.,
Alioramus,Tyrannosaurus).
Dorsomedial maxillary fenestra (dmmf). Elongated ap-
erture located on the medial surface of the maxilla and perforating
the dorsal wall of the maxillary antrum and, in some cases,
promaxillary recess (Fig. 1F). The dorsomedial maxillary fenestra,
corresponding to the subnarial fenestra of [46], is present in some
Allosauroidea such as Sinraptor (IVPP 10600; [45]:fig. 4.12) and
Allosaurus ([24,46]; USNM 8335), the troodontid Troodon [58] and
possibly some tyrannosaurids such as Alioramus [25].
Anteromedial maxillary fenestra (ammf). Aperture with-
in the anterior wall of the maxillary antrum (preantral strut) and
leading to the promaxillary recess (Fig. 1E, 2C). An anteromedial
maxillary fenestra, corresponding to the fenestra communicans
sensu [24], exists in the majority of allosauroid and tyrannosauroid
theropods.
Accessory maxillary fenestra (amf). Aperture located
within a fossa dorsomedial to the maxillary fenestra, dorsal to
the posteromedial maxillary fenestra, and leading to the maxillary
antrum (Fig. 3C2). Several accessory maxillary fenestrae have
been noticed in one maxilla (CMNH 9380) of Tyrannosaurus.
Medial maxillary fenestra (mmf). Subtriangular aperture
perforating the medial wall of the maxilla and leading laterally to
the maxillary antrum and promaxillary recess. The medial
maxillary fenestra is delimited by the postantral strut posteriorly,
the suprantral strut dorsally, the medial shelf ventrally and the
anterior corner of the promaxillary recess anteriorly. Its presence
has only been noticed in some basal allosauroids such as Sinraptor
and Allosaurus.
Antrum and Recesses
Maxillary antrum (man). Large cavity located between the
lateral and medial walls, anterior to the medial antorbital fossa,
and communicating laterally with the maxillary fenestra [24]
(Figs. 1C, E, 2C). The maxillary antrum [24] can also lead to the
promaxillary recess via the anteromedial maxillary fenestra. The
walls of the maxillary antrum can be reinforced by several struts
(see below) that can be fenestrated. The maxillary antrum is also
known as the maxillary sinus (e.g., [45,46]) but the latter may refer
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to the sinus invading both maxillary antrum and promaxillary
recess [24].
Promaxillary recess (pmr). Cavity variable in volume
within the medial wall, anterior to the maxillary antrum, and
communicating laterally with the promaxillary fenestra (Figs. 1C,
E, 2C). The promaxillary recess [24] is also known as the
promaxillary sinus (e.g., [25,37,80]).
Epiantral recess (epi). Small depression situated on the
medial surface of the maxilla, posterodorsal to the maxillary
fenestra, and excavating the anterodorsal surface of the inter-
fenestral strut (Figs. 1C, E, 2C). An epiantral recess [24] is present
in Allosauroidea (e.g., Sinraptor,Allosaurus) and Tyrannosauroidea
(e.g., Alioramus,Raptorex,Tyrannosaurus,Tarbosaurus).
Interalveolar recess (iar). Diverticula within the medial
wall and the medial shelf and directed ventrally from the maxillary
antrum and promaxillary recess, between the maxillary teeth
(Fig. 3C1–2). An interalveolar recess, also known as the
interalveolar pneumatic recess (recessus pneumatici interalveolares
sensu [24]) is only present in Tyrannosauridae like Alioramus,
Albertosaurus and Tyrannosaurus ([24,25], pers. obs.).
Foramina and Grooves
Subnarial foramen (snf). Small opening variable in outline
and located between the premaxilla and maxilla, below the
external naris (Fig. 1A). The subnarial foramen corresponds to the
maxilla-premaxillary fenestra of [67,68] and the subnarial fenestra
of [81].
Anterodorsal foramen (adf). Small opening located on the
anterodorsal margin of the maxilla and perforating the dorsome-
dial wall of the promaxillary recess. The anterodorsal foramen is
present in some troodontids such as Troodon [58].
Nutrient groove (nug). Furrow running anterodorsally on
the medial surface of the maxillary body and hosting the nutrient
foramina (Figs. 1C, 2C). The nutrient groove, also known as the
groove for the dental lamina (e.g., [35,37,50]) and the paradental
groove (e.g., [29,36,82]), corresponds to the junction between the
interdental plates and the medial wall. Due to the fact that the
medial wall slightly overlap the interdental plates medially, the
nutrient groove is delimited by the interdental plates laterally and
the medial wall medially, and by both interdental plates and
medial wall dorsally and ventrally. A similar groove, the
paradental groove, exists on the medial surface of the dentary,
ventral to the interdental plates.
Nutrient foramina (nuf). Small openings on the interdental
plates, at the level of the nutrient groove, permitting the unerupted
teeth to be innervated by blood vessels inside their alveoli [49]
(Figs. 1C, 2C). Also known as nutrient notches (e.g., [47,83]),
suprainterdental plate foramina [27], or dental foramina (e.g.,
[53,68,84]).
Interdental gap (idg). Ventrodorsally elongated groove
separating each interdental plate while they are unfused (Fig. 2C).
Maxillary neurovascular foramina (mnf). Small openings
located on the lateral surface of the maxillary body and permitting
the passage of blood vessels to innervate the lips and cheeks.
Maxillary alveolar foramina (maf). Row of neurovascular
foramina parallel with and adjacent to the ventral margin of the
maxilla (Figs. 1A, 2B).
Maxillary median foramina (mmf). Neurovascular foram-
ina randomly distributed and located in between the rows of
maxillary alveolar and circumfenestra foramina (Fig. 1A).
Maxillary circumfenestra foramina (mcf). Row of neu-
rovascular foramina parallel with and adjacent to the ventral rim
of the antorbital fossa (Figs. 1A, 2B).
Maxillary Struts
Promaxillary strut (prms). Lamina or column separating
the promaxillary fenestra from the maxillary fenestra (Fig. 2B).
The promaxillary strut (pila promaxillaris sensu [24]), as called by
several authors (e.g., [32,49,59]), is also known as the promaxillary
pila (e.g., [85,86]).
Interfenestral strut (ifs). Bone wall separating the maxillary
fenestra from the antorbital fenestra (Figs. 1A, 2B, C). The
interfenestral strut (pila interfenestralis sensu [24]), is also known as
the interfenestral bar (e.g., [56,59,63,83,85]).
Postmaxillary strut (ptms). Bone surface separating the
maxillary fenestra from the postmaxillary fenestra (Fig. 3D). Only
present in Tyrannosauridae (e.g., BHI 3033, LACM 23844, ZPAL
MgD-I/4).
Postantral strut (poas). Pillar of bone delimiting the
posteromedial maxillary fenestra medially, and the maxillary
antrum posteromedially (Figs. 1C–F, 2C, 3A, C2). The postantral
strut (pila postantralis sensu [24]) can be fenestrated by the
posteromedial maxillary fenestra, allowing communication of the
antorbital cavity and the maxillary antrum [24].
Suprantral strut (suas). Ridge reinforcing the dorsal wall of
the maxillary antrum dorsomedially (Fig. 1E). The suprantral strut
can be perforated by the dorsomedial maxillary fenestra [24].
Preantral strut (pras). Pillar of bone separating the
maxillary antrum from the promaxillary recess (Figs. 1C, E, 2C).
The preantral strut, corresponding to the maxillary septum sensu
[46], can be doubled (i.e., presence of lateral and medial preantral
struts) when the promaxillary fenestra is internal (i.e., within the
maxilla and the maxillary antrum) as in Allosaurus (Fig. 1E).
Results
Systematic Paleontology
Dinosauria Owen, 1842 [87]
Saurischia Seeley, 1887 [88]
Theropoda Marsh, 1881 [89]
Tetanurae Gauthier, 1986 [66]
Megalosauroidea Fitzinger, 1843 [90]
Megalosauridae Fitzinger, 1843 [90]
Torvosaurus Galton & Jensen, 1979 [91]
Revised diagnosis. Megalosauroid theropod with very
shallow maxillary fossa (i.e., maxillary fossa forming a poorly
delimited concavity in the anterior corner of the lateral antorbital
fossa) [61], protuberant ridge below the maxillary fossa, in the
ventral part of the anterior corner of the lateral antorbital fossa,
interdental wall making up one-half the medial surface of the
maxillary body (modified from [27]), expanded fossae in posterior
dorsal and anterior caudal centra forming enlarged and deep
pneumatic openings [61], highly ossified puboischiadic plate [61],
and distal expansion of ischium with prominent lateral midline
crest and oval outline in lateral view [61].
Torvosaurus tanneri Galton & Jensen, 1979 [91]
Galton & Jensen ([91]:figs. 1, 2, 3A, G, L, 4A–F, 4I–N; 6–7,
8H); Jensen ([92]:figs. 1–4A–D, E–F, 5A–F, H); Britt ([27]:figs. 2–
24)
1988 Megalosaurus tanneri; [91]; [93], p. 282.
1992 Edmarka rex gen. nov.; [94]:figs. 1, 3, 7, 10, 12–15.
1997 ‘Brontoraptor’ sp. gen. nov.; [95]:figs. 1–9, 10A–E, 11A–E,
12–13A, 14–15A, 16A–H, 17 (nomen nudum).
Lectotype. BYU-VP 2002, left humerus ([27]).
Paralectotype. BYU-VP 2002, the rest of left and right
forelimbs ([27]).
Referred material. (from [61]) BYU-VP 2003, 2004, 2005,
2006, 2007, 2008, 2016, 2017, 4838, 4853, 4860, 4882, 4883,
Torvosaurus from Portugal
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4884, 4890, 4908, 4951, 4952, 4976, 4998, 5004, 5005, 5008,
5009, 5010, 5020, 5029, 5077, 5086, 5092, 5110, 5129, 5136,
5147, 5242, 5254, 5276, 5277, 5278, 5279, 5280, 5281, 5286,
8907, 8910, 8937, 8938, 8966, 8982, 9013, 9090, 9108, 9120,
9121, 9135, 9136, 9141, 9142, 9143, 9144, 9152, 9161, 9162,
9163, 9249, 9620, 9621, 9622, cranial and postcranial elements
[27]; TATE 401, 1002–1005 (Edmarka rex), jugal, scapulocoracoid,
and ribs [94]; TATE 0012, with 0012-11 formally 1003,
(‘Brontoraptor’), atlas, axis, sacrum, caudal vertebrae, chevrons,
scapula, coracoids, ilium, pubis, ischium, femur, tibia, fibula [95];
FMNH PR 3060, three midline fragments of gastralia, right
metacarpal III, right manual phalanx III-2, left metatarsals II–IV,
left pedal phalanx I-1 [96].
Locality and horizon. Dry Mesa Quarry, Montrose County,
Calico Gulch Quarry, Uncompahgre Plateau, Moffit County, and
Meyer site, Garden Park, north of Can˜on City, Fremont County,
Colorado; Carnegie Quarry, Dinosaur National Monument,
Uintah County, Utah; Gilmore Quarry N and Quarry 6,
Freezeout Hills, Carbon County, and Nail and Louise Quarries,
Como Bluff, Albany County, Wyoming, USA; Salt Wash and
Brushy Basin Members, Morrison Formation; Kimmeridgian-
Tithonian, Late Jurassic [61,96].
Diagnosis. Megalosauroid theropod with a protuberant ridge
on the anterior part of the medial shelf, posterior to the
anteromedial process, and an interdental wall falling short relative
to the lateral wall (i.e., ventral margin of the interdental wall much
more dorsal than the ventral margin of the lateral wall) and
formed by the fusion of interdental plates with broad V-shaped
ventral margin.
Torvosaurus gurneyi Hendrickx & Mateus 2014 sp. nov. urn:lsid:-
zoobank.org:act:189C1060-7887-4837-9E30-870079E2B2B9
(Fig. 4).
Torvosaurus tanneri Mateus et al. ([4]:fig. 6).
Holotype. ML 1100, an incomplete left maxilla (Figs. 4B, 5–
6) bearing one erupted tooth and one unerupted tooth (Fig. 7), and
the posterior portion of a proximal caudal vertebra (Fig. 8).
Referred material. ALT-SHN.116, a portion of a right
maxilla [8]. ML 962, a mesialmost shed tooth ([6]:fig. 9), FUB PB
Ther 1, a lateral tooth, ML 430, an incomplete tibia [7], ML 632,
a partial femur [4], and ML 1186, cranial and postcranial material
of embryos [9], are tentatively referred to T. gurneyi.
Type. Cliffs of Praia da Vermelha, Lourinha˜, Portugal. Porto
Novo-Amoreira Member, Lourinha˜ Formation, Upper Kimmer-
idgian, Upper Jurassic [21].
Etymology. In honor of the paleoartist James Gurney,
creator of the utopic world of Dinotopia.
Diagnosis. Megalosauroid theropod with maxillae bearing
fewer than eleven teeth and possessing fused interdental plates
with straight ventral margin forming an interdental wall nearly
coincidental with the lateral wall of the maxillary body. Differs
from Torvosaurus tanneri by fewer than eleven maxillary alveoli, the
absence of interdental plates terminating ventrally by broad V-
shaped points and falling short relative to the lateral wall, the
absence of a protuberant ridge on the anterior part of the medial
shelf, posterior to the anteromedial process, and the coincidental
posterior extension of the dorsal and medial ridges of the
anteromedial process.
Taphonomy. The specimen was found in beach eroded
boulders that fell from the sea cliff. The bones did not show any
signs of articulation, except the maxilla preserving the teeth in situ.
The elements are not visibly compressed or deformed. The caudal
centrum, directly associated with the maxilla and showing some
Torvosaurus characters, has three patched of pyrite encrustations
and attached to charcoal. This suggests taphonomical or
depositional anoxic conditions.
Description
Maxilla. A fairly complete and undistorted left maxilla (Fig. 5)
was collected in Praia da Vermelha in June 2003 [4]. Some bone
surfaces on the lateroposterior side of the anterior ramus and on
the anterodorsal corner of the lateral antorbital fossa are missing.
Likewise, some bone fragments on the medial surface of the jugal
ramus, including the posteriormost alveoli, are absent. The maxilla
is also broken in two pieces at the level of the third alveolus, and a
fragment of the lateral surface of the maxilla can be removed at
the level of alveolus 4, allowing examination of a complete
unerupted tooth (Figs. 5–6A). Only a fully-erupted tooth, the
second maxillary tooth, is preserved, and the crown tips of the
third and six alveoli are visible. The maxilla is thick and massive,
with a short posterodorsally angled ascending ramus and a high
anteroposteriorly elongated maxillary body (Fig. 5–6A; Table 1).
The ventral margin of the maxillary body is weakly sigmoid, with a
convex, almost straight, ventral margin of the anterior body, and a
concave ventral margin of the jugal ramus.
The anterior body of the maxilla is longer than the jugal ramus
(Table 1), yet the posterior extremity of the jugal ramus is broken
and the posterior part may have extended further posteriorly.
Nevertheless, the anterior body is high and about one third higher
than the jugal ramus at its anteriormost part (Figs. 5–6A). The
Figure 4. Reconstruction of in lateral view. A, Skeletal reconstruction of Torvosaurus gurneyi in lateral view illustrating,
in red, the elements present in the holotype specimen (ML 1100) and, in blue, the elements tentatively assigned to this species (artwork by Scott
Hartman, used with permission and modified; drawing of man by Carol Abraczinskas, University of Chicago, used with permission). B, Skull
reconstruction of Torvosaurus gurneyi in lateral view illustrating the incomplete left maxilla(ML 1100) of the holotype specimen (artwork by Sima
˜o
Mateus, used with permission and modified). Scale bars = 1 m (A) and 10 cm (B).
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Torvosaurus gurneyi
dorsal rim of the anterior body is convex and anteroventrally
inclined. It mostly includes an anterior ramus which is demarcated
by concave step on the anterodorsal margin of the maxilla. Both
anterior ramus and preantorbital body have similar anteroposte-
rior extensions along the maxillary body. The anterior ramus is
particularly high and elongated, and its posterior rim is concave
whereas its ventral margin is straight. The anterior rim of the
anterior ramus is high (about two thirds of the anterior ramus
height in its highest part), subvertical, and perpendicular to the
ventral margin of the maxillary body. The outline of the anterior
margin is irregular and roughly sigmoid in lateral view, the ventral
half is convex while the dorsal half is concave due to the presence
of a ventrodorsally wide subnarial foramen. The dorsal margin of
the anterior ramus bears a thin crest, the anterodorsal crest
(Figs. 5–6D–E), running from alveoli 1 to 3 and adjacent to the
anteromedial process. This narrow crest is slightly medially
inclined and taller in its anterior part. It also shows an undulating
dorsal rim. The anteromedial process and the anterodorsal crest
both delimit a deep anteroposteriorly extended groove that
received the ventral articular surface of the nasal. The nasal
contact of the anterior ramus is narrow and shallow in its posterior
part, anterior to the ascending ramus, and gets wider and deeper
at the level of the anteromedial process.
The premaxillary contact is located on the anterior rim of the
anterior ramus. It is a rather simple articulation that corresponds
to a roughly flat but uneven surface. The premaxillary articulation
bears two large foramina on its dorsalmost part, the smaller one
being situated dorsolateral to the larger one, in the dorsolateral
corner of the premaxillary contact. These two anterior foramina
(Fig. 5–6E) lead to the subnarial foramen, an aperture that is
posteriorly delimited by the maxillary body and the maxillary
contact of the premaxilla anteriorly. The subnarial foramen is not
clearly visible but corresponds to a wide concavity on the
anterolateral margin of the maxillary body, at the dorsalmost
third of the premaxilla contact. Additional foramina are visible
medial to the anterior foramina, and along the ventral half of the
premaxillary contact. These additional foramina are minute in
size, and smaller than the two anterior foramina (Figs. 5–6E). Two
pits also exist on the dorsalmost part of the premaxillary contact,
between the lateral wall of the anterior ramus and the medial wall
attached to the anteromedial process. These two pits accommo-
dated the bifurcated maxillary process of the premaxilla. In
anterior view, the medial margin of the premaxillary articulation is
straight whereas the lateral margin is convex. In medial view, the
lateral wall of the anterior ramus extends slightly further anteriorly
than the medial wall.
The jugal ramus is sub-triangular in outline and tapers gently
ventroposteriorly. The surface of the jugal ramus bears a small and
shallow concavity on its anterolateral margin, at the level of
alveolus 6. This concavity is bounded ventrally by the antorbital
ridge. A wide furrow is visible on the dorsomedial surface of the
jugal ramus, ventral to the antorbital fenestra. This groove most
likely corresponds to a neurovascular opening serving for the
passage of the maxillary branch of the trigeminal nerve (O.
Rauhut, pers. comm.). The neurovascular opening (Fig. 6B–G)
runs from the lacrimal contact of the maxilla to the level of the
Figure 5. Maxilla of
Torvosaurus gurneyi
(ML 1100) and comparison with
T. tanneri
.Incomplete left maxilla of the holotype specimen of
Torvosaurus gurneyi (ML 1100) in A, lateral; B, medial; C, ventral; D, dorsal; E, anterior; F, posterior views with details of G, Anterodorsal margin of
jugal ramus in dorsomedial view; and H, Posterior part of jugal ramus in dorsal view. I–J, Anterior part of interdental wall of I,T. gurneyi; and J,T.
tanneri (BYUVP 9122) in medial view. K–L, Anteromedial process of K,T. gurneyi; and L,T. tanneri (BYUVP 9122) in medial views. Scale bars = 10 cm
(A–H), 5 cm (G–L).
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eighth alveolus, just below the antorbital fenestra. The groove is
shallow anterior to the lacrimal contact but penetrates deeply
inside the medial wall of the jugal ramus in its anterior part. The
jugal articulates with the posterior extremity of the jugal ramus,
along a smooth articular surface on the lateroventral margin of the
jugal ramus. The anterior rim of the jugal contact is parabolic in
outline, and the main axis of the articulation is inclined
ventroposteriorly. Its ventral rim corresponds to a narrow groove
penetrating the lateral wall of the jugal ramus.
A second articulating surface, the lacrimal contact, appears on
the posteromedial margin of the jugal ramus, posterior to the
neurovascular opening, and at two thirds of the jugal ramus
(Fig. 6B). The lacrimal contact extends along the posterior
extremity of the jugal ramus, posterior to the eighth alveolus.
The lacrimal contact covers around one half of the jugal ramus.
The dorsal rim of the lacrimal contact forms a convexity on the
dorsal margin of the jugal ramus, and the ventral part consists of a
very deep slit inside the jugal ramus, so that the maxillary contact
of the jugal corresponded to very thin articular structure (Fig. 6F–
H). The lacrimal contact also includes a second furrow running
along the dorsomedial rim of the jugal ramus, medial to the deep
split and dorsal to the lateral part of the lacrimal
articulation(Fig. 6H). The latter is bounded laterally by the lateral
wall of the maxillary body on its anterior part, its posterior part
being adjacent to the jugal contact on the lateroposterior surface of
the jugal ramus. The main axis of the lacrimal contact is directed
posteroventrally, parallel to the ventral rim of the antorbital
fenestra. Similar to the jugal contact, the lacrimal contact of the
jugal ramus is a simple suture i.e., it is not reinforced by a series of
grooves and rugosities.
Figure 6. Maxilla of
Torvosaurus gurneyi
(ML 1100) and comparison with
T. tanneri
.Interpretive line drawing of the left maxilla of the
holotype specimen of Torvosaurus gurneyi (ML 1100) in A, lateral; B, medial; C, ventral; D, dorsal; E, anterior; F, posterior views with details of G,
anterodorsal margin of jugal ramus in dorsomedial view; and H, posterior part of jugal ramus in dorsal view. I–J, Interpretive line drawing of the
anterior part of interdental wall of I,T. gurneyi; and J,T. tanneri (BYUVP 9122) in medial view. K–L, Interpretive line drawing of the anteromedial
process of K,T. gurneyi; and L,T. tanneri (BYUVP 9122) in medial views. Hatched areas represents missing parts, light grey tone indicates
reconstructed part, and dark grey tone corresponds to the pneumatopores, foramina, and alveoli, with alveoli 9 and 10 being reconstructed.
Abbreviations: adc, anterodorsal crest; adr, anterodorsal ridge of the anteromedial process; afo, anterior foramina; al, alveolus; amg, anteromedial
groove of the anteromedial process; amp, anteromedial process; amr, anteromedial ridge; anr, anterior ramus; aor, antorbital ridge; asr, ascending
ramus; avg, anteroventral groove of the anteromedial process; avr, anteroventral ridge on the anteromedial process; dmg, dorsomedial groove;
idw, interdental wall; juc, jugal contact; lac, lacrimal contact; laof, lateral antorbital fossa; law, lateral wall; maf, maxillary alveolar foramina; mcf,
maxillary circumfenestra foramina; mes, medial shelf; mew, medial wall; mfo, maxillary fossa; mx, maxillary teeth; nac, nasal contact; nuf, nutrient
foramina; nug, nutrient groove; nvo, neurovascular opening; pmc, premaxillary contact; snf, subnarial foramen. Scale bars = 10 cm (A–H), 5 cm (G–
L).
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The ascending ramus forms a wing-like structure diverging from
the maxillary body to an angle of around 30uwith the ventral
margin (Figs. 5–6A). The ascending ramus is short compared to
the anteroposterior extension of the maxillary body (Table 1), but
its posterior extremity is broken and must also have extended
further posteriorly (Fig. 4). Although some parts of the anterior
margin of the ascending ramus are missing, the anterior and
posterior rims are sub-parallel along the anterior part of the ramus
but the anterodorsal rim abruptly changes orientation at two thirds
of the process so that the jugal ramus tapers posteriorly. The
medial surface of the ascending ramus is slightly concave, and a
small depression appears on the posteromedial surface of the
ascending ramus, on the centre of the process. Unlike other
articular surfaces on the maxilla, the lacrimal contact of the
ascending ramus is not clearly delimited. A few parallel ridges are
visible on the lateroposterior surface of the ascending ramus, and
the lacrimal contact is bounded by a sharp ridge parallel to the rim
of the antorbital fenestra on its ventromedial surface. A furrow is
also present on the posterolateral margin of the ascending ramus
and was bordering the anterior rim of the lacrimal. This wide
groove runs diagonally on the posterior extremity of the ascending
ramus and is bounded by a short crest anteriorly. Two shallow
concavities appear anterior to this ridge and their main axis is sub-
parallel to the diagonal furrow.
The anteromedial process of the maxilla is complete, protuber-
ant and clearly-visible on the anterodorsal corner of the anterior
body, immediately ventral to its dorsal rim, and to a certain
distance dorsal to the nutrient groove (Figs. 5–6B, K). This process
sweeps gradually and tapers ventrally at the level of the first
alveolus. It bears two large and parallel ridges separated by a wide
groove on its medial surface, and a shallow and straight groove on
its ventromedial surface (Fig. 6K). Both ventral and dorsal ridges
Figure 7. Dentition of
Torvosaurus gurneyi
(ML 1100). A, C, E–H, Second maxillary tooth; and B, D, third non-erupted maxillary tooth of the
holotype specimen of Torvosaurus gurneyi in A–B, labial; C–D, lingual; E, mesial; F, distal; G, basal; and H, apical views. I–J, Distal; and K–M, mesial
denticles of the second maxillary tooth in lateral view. M, Distal serrations showing the interdenticular sulci; and N, enamel texture of the third non-
erupted tooth in labial view. Abbreviations: cd, cervix dentis; dca, distal carina; del, dentine layer; ent, enamel texture; ids, interdenticular sulci;
idsp, interdenticular space; mca, mesial carina; lic, lingual concavity for the erupting tooth; puc, pulp cavity; ro, root; uet, unerupted tooth; und,
transversal undulation. Scale bars = 5 cm (A–F), 3 cm (G–H), 3 mm (I, K, M–N), 1 mm (J, L).
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Figure 8. Caudal vertebra of
Torvosaurus gurneyi
(ML 1100). A–
D, Posterior part of an anterior caudal centrum of the holotype
specimen of Torvosaurus gurneyi (ML 1100) in A, anterior; B, posterior;
C, right lateral; D, left lateral; E,dorsal;andF, ventral views.
Abbreviations: nc, neural canal; st, striation. Scale bar = 5 cm.
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get flared at the level of the third alveolus posteriorly, and the wide
groove they delimit gets deeper anteriorly. The anteromedial
process does not extend further than the third alveolus posteriorly,
and only expands slightly further than the anterior rim of the
maxillary body anteriorly.
The medial shelf is poorly delimited. It corresponds to a wide
but shallow ridge running on the medial wall of the maxillary
body, from the anteromedial process to the posterior part of the
jugal ramus (Figs. 5–6B). The medial shelf is clearly sigmoid i.e., it
is convex along the jugal ramus and concave along the anterior
ramus. A subtle flattened surface is visible at the level of the fourth
alveolus, posteroventral to the anteromedial process. There is no
trace of articulating surface for the palatine on the preserved
medial shelf. The palatine may have been in contact with the
medial margin of the maxillary body posterior to the eighth
alveolus, yet the palatine articulation may have just been eroded
more anteriorly.
The surface of the medial wall is smooth all along the maxilla. It
bears two concavities just ventral to the anteromedial process, at
the level of the first and second alveoli (Fig. 6K). The anterior
concavity is significantly wider than the posterior one and
subcircular in outline. The posterior depression is weakly
ventrodorsally elongated and subrectangular in outline. These
two deep pits accommodated two large crowns of the dentary
while the jaws of the animal were closed. A deep depression occurs
on the anterodorsal surface of the anterior body, beneath the
anterior part of the anteromedial process. This depression is
bounded dorsally by a thin convex lamina linking the anterome-
dial process to the anterior ramus. The medial wall is neither
fenestrated nor perforated at the base of the ascending ramus, and
there is no trace of medial antorbital fossa and medial pneumatic
complex.
The nutrient groove is distinct and forms a strong step between
the medial wall and the interdental plates (Figs. 5–6B). The groove
is sigmoid and subparallel to the medial wall, and strongly curves
ventrally at the level of the second alveolus. It bears seven clearly-
visible nutrient foramina at the level of each alveolus, exactly
aligned with their centre (Figs. 5–6B). The nutrient foramen of the
third, eighth and more posterior alveoli are not preserved. These
dental foramina increase in size with the fourth alveoli and then
decrease in dimension more posteriorly. They are lanceolate to
elliptical in outline, the largest one being almost subcircular at the
level of the fourth alveolus. The nutrient foramina weakly
penetrates the medial wall dorsally.
The interdental plates are completely fused to form a
continuous lamina along the medial surface of the maxillary body
(Figs. 5–6B, I). Their height increases along the two first alveoli,
then their ventrodorsal extension decreases posterior to alveolus 3.
They are particularly high at the level of the second and third
alveolus, being twice higher than wide, and the ventral extend of
the interdental wall is as far ventral as the lateral wall of the
maxillary body. The medial surface of the interdental plates is
irregular and rugose, and the presence of faint grooves running
ventrodorsally on the ventral margin can be noticed (Fig. 6I).
The antorbital fenestra is almost perfectly parabolic in outline
i.e., the curvatures of the ventral and dorsal rims of the antorbital
fenestra are subsymmetrical, the ventral margin being only slightly
wider ventrally. The medial antorbital fossa is absent but the
lateral antorbital fossa extends far anterior on the maxilla. The
extension of the lateral antorbital fossa is important on the
ascending ramus but limited to the dorsalmost part of the
maxillary body. The lateral antorbital fossa is bounded ventrally
by a wide and poorly delimited antorbital ridge on the dorsal part
of the jugal ramus (Figs. 5–6A). The antorbital ridge is missing in
the dorsal part of the anterior body and all along the ascending
ramus so that it is not possible to know the exact extension of the
antorbital fossa in its anteriormost corner.
No promaxillary or maxillary fenestrae are present within the
lateral antorbital fossa. Nevertheless, a subtriangular depression is
visible on the anterior corner of the antorbital fossa, just anterior
to the anteriormost point of the antorbital fenestra and dorsal to
the antorbital ridge of the anterior body. Due to its large size,
shape and location, the subtriangular depression is here interpret-
ed as homologous to the maxillary fossa (or imperforated maxillary
‘fenestra’ of [41]). A single accessory antorbital fossa occupying
most of the anterior corner of the lateral antorbital fossa has
usually been interpreted as being a maxillary fossa/fenestra rather
than a promaxillary fossa/fenestra, and the latter is only large
when associated to the maxillary fenestra (pers. obs.). It is very
likely that the antorbital ridge was forming a lateral rim on the
anteroventral part of the ascending ramus, delimiting a deep recess
within the anterior corner of the lateral antorbital fossa. The
Table 1. Measurements of left maxilla of the holotype of Torvosaurus gurneyi (ML 1100).
Measurements (mm)
Anteroposterior length of maxilla: 612
Dorsoventral depth of maxilla at the posteriormost point of the ascending ramus: 274
Dorsoventral depth of maxillary body at the level of the step delimiting the anterior ramus and ascending ramus: 226
Anteroposterior length of antorbital body: 310
Anteroposterior length of jugal ramus: 299
Dorsoventral depth of jugal ramus at the anterior margin of antorbital fenestra: 170
Dorsoventral depth of ascending ramus along its main axis: 237
Dorsoventral depth of anterior margin of maxillary body: 122
Anteroposterior length of anteromedial process 115
Anteroposterior length of jugal contact: 83
Dorsoventral depth of interdental wall at the level of the third alveolus: 106
Basoapical length of second maxillary tooth, root included: 138
Basoapical length of third non-erupted maxillary tooth, root included: 165
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posteriormost part of a poorly defined ridge is visible dorsal to the
antorbital ridge, on the anterodorsal part of the jugal ramus, at the
level of the fourth alveolus. Although this ridge is strongly
damaged more anteriorly, its posterior rim can be followed from
the antorbital fenestra to the anteriormost part of the maxillary
recess.
The texture of the lateral surface of the maxilla is not rugose or
sculptured, but the lateral surface of the maxillary body is pierced
by a series of large, deep and well-delimited neurovascular
foramina. A wide groove, parabolic in outline in some cases,
extends ventrally from each neurovascular foramina which
penetrate the lateral wall of the maxilla dorsally. Although many
neurovascular foramina are missing due to damage of the lateral
bone surface, two rows of neurovascular foramina are clearly
visible and both run anteroposteriorly on the maxillary body,
parallel to the ventral margin. The ventral row, which includes the
maxillary alveolar foramina, is adjacent and slightly dorsal to the
ventral margin of the maxillary body, whereas the dorsal row, that
encompasses the circumfenestra foramina, is centrally positioned
on the maxillary body and runs shortly dorsally to the row of
alveolar foramina.
Eight maxillary alveoli are distinctly visible along the maxillary
body, and the preserved posterior part of the jugal ramus does not
preserve any alveolus (Figs. 5–6C). The tooth row extends anterior
to the jugal contact, and the largest tooth-sockets are located at
mid-length of the maxillary body, the largest alveolus being the
sixth one. The alveoli are well-separated and elliptical in outline all
along the tooth row.
Dentition. The second fully erupted maxillary tooth and the
third unerupted tooth (Figs. 5–7) are well preserved and allow the
crown and denticles morphology to be investigated comprehen-
sively. The second erupted tooth is complete and undistorted while
the unerupted one has been crushed inside its alveolus and the
labial and lingual surfaces are damaged. The apical part of a third
unerupted tooth appears on the basolingual surface of the
unerupted tooth, inside the fourth alveolus (Fig. 7D). This second
unerupted crown correspond to the third generation of teeth in the
maxilla.
The crowns are ziphodont (i.e., blade shaped, labiolingually
compressed, distally curved and having serrated carinae), large
(crown height .100 mm; Table 2) and strongly elongated (crown
height ratio .2.5; [6]). They are significantly recurved distally and
bear prominent carinae mesially and distally. In distal view, the
crown and the distal carina of the erupted tooth are gently sigmoid
in outline, with the root curving lingually from the crown (Fig. 7F).
The basolabial surface of the erupted crown is mesiodistally
concave and this depression allows the accommodation of an
unerupted crown lingually. The distal carina extends to the cervix
whereas the mesial carina does not reach the root and gets flared
at one third of the crown (Fig. 7E). Both carinae are centrally
positioned on the crown although the basal part of the mesial
carina tends to get slightly offset at mid-height of the crown. The
cross section outline of the crown is reniform at the cervix,
lanceolate at one third of the crown and elliptical more apically.
The external surface is particularly well-preserved and shows a
clear braided and basoapically oriented texture of the enamel
(Fig. 7N). Although not present on the erupted crown, subtle
transversal undulations (‘‘enamel wrinckles’’ sensu [97]) are
observable on the basal half of the unerupted crown, on both
labial and lingual sides (Fig. 7B, D). The undulations are more
pronounced adjacent to the distal carina on the lingual surface of
the crown. Only the basal part of the root of the second maxillary
tooth is preserved. The root clearly shows a deep concavity on its
lingual surface for receiving the unerupted crown. Such lingual
concavity is also present on the other teeth of the maxilla as the
cross section outline in the root of these teeth is clearly reniform.
The denticles are large and coarse, with an average of eight
denticles per five millimetres on both carinae (Fig. 7I–M; Table 3).
The crown apex is damaged in the erupted crown, but the
serrations are clearly crossing the apex of the unerupted tooth. In
the second maxillary crown, there is a density of ten to eleven
denticles per five millimetres basodistally, eight denticles at mid-
crown and six to seven serrations per five millimetres apically for
both carinae, so that the denticle size increases from the base to
the apex (Table 3). Mesial and distal denticles of both erupted and
unerupted crown differ in their morphology and elongation. The
distal denticles are chisel-like in shape (i.e., denticles with a sharp
edge) in mesial and distal views and finger-like in shape (i.e.,
horizontal subrectangular denticles with convex labial and lingual
surfaces) in lateral view (Fig. 7I–J). They extend perpendicularly
from the distal margin of the crown and possess narrow but deep
interdenticular space. The external margin of each denticle is
symmetrically to asymmetrically convex but never hooked
apically. Pronounced and clearly-visible interdenticular sulci are
present all along the distal carina (Fig. 7M). These grooves curve
basally from each interdenticular space and are particularly long at
mid-crown. They are shorter more basally and apically, being very
short to absent near to the cervix and the apex. Unlike the distal
serrations, the mesial denticles have subquadrangular to vertical
subrectangular profile in lateral view (Fig. 7K–L). They are either
perpendicular to or weakly apically inclined from the mesial
margin of the crown, and their external margin is symmetrically to
asymmetrically convex. The interdenticular space is deep and
tends to be basoapically wider at mid-height and narrower at the
level of the apex in some denticles, creating an elliptical to
lanceolate outline of the interdenticular space. The interdenticular
sulci are short or totally absent from mesial serrations. On the
unerupted tooth where they are clearly visible, they are short to
absent on the lingual side but totally absent on the labial surface of
the crown.
Table 2. Measurements of maxillary teeth of the holotype of
Torvosaurus gurneyi (ML 1100).
Measurements
(mm)
Second erupted maxillary tooth
Crown base length (CBL) 45.52
Crown base width (CBW) 16.4
Crown height (CH) 106.4
Apical length (AL) 118.57
Mid-crown length (MCL) 33.1
Mid-crown width (MCW) 16.8
Extension of mesial denticles from cervix (MDE) 55.51
Third unerupted maxillary tooth
Crown base length (CBL) 45.65
Crown base width (CBW) ?
Crown height (CH) 116.98
Apical length (AL) 128.59
Mid-crown length (MCL) 39.54
Mid-crown width (MCW) ?
Extension of mesial denticles from cervix (MDE) 46.38
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Several isolated bone fragments, including the proximal portion
of a rib, a strongly damaged fragment of a long bone and a caudal
vertebra, have been uncovered from the same area of the maxilla.
Nevertheless, only the caudal vertebra comes from the same spot
and was directly associated with the maxilla. Likewise, its size,
preservation and taxonomic identification allows assigning the
caudal vertebra to the same specimen with confidence.
Caudal vertebra. The posterior third of a caudal centrum
(Fig. 8) with about 57 mm is preserved. We interpret this bone as a
proximal caudal vertebra based on comparisons with the T. tanneri
holotype (BYU-VP 13745), in particular based on the lack of an
elongated pneumatic foramen extending along most of the
centrum length, shallow chevron facets and the flattened to sub-
convex articular surface. The general outline of the posterior view
forms a large ellipse about 131 mm tall and 120 mm wide
(Table 4). The articular facet is moderately flat; however, in the
middle of the surface there is a tuberosity projecting posteriorly,
and shallow depressions below and above it are also visible
(Fig. 8E). The lateral and ventral margin of the centrum have well-
defined striations that run anteroposteriorly on the centrum, being
deeper and pronounced in the ventral half the centrum (Fig. 8A,
F). These sulci are up to 20 mm long, 2 mm wide, and 1.2 mm
deep, but the dimensions vary. These dimensions provide a density
of 3.5 ridges per centimetre. The ventroposterior corner of the
centrum is expended but with no clear individual facet for the
chevrons. The posterior rim if the centrum possesses circular
striations. There is a horizontal transversal groove on the
posteroventral corner of the centrum between the ventralmost
rim of the centrum and the platform of the articular facet. This
gives a salient aspect to the posterior region of the centrum, but
this can also be interpreted as a sub-convexity of this facet. The
anterior broken transversal section has an amphora-like outline.
This outline is produced ventrally by a rounded ridge-like midline
crest, and dorsally by the posterodorsal corner of the centrum that
is slightly narrower transversely, giving a constriction of the
amphora-like outline (Fig. 8A). The bone is compact towards the
periost, and camellate in the anterior part of the centrum. The
neural canal is narrow ventrally which gives a V-shape at the
cross-section in anterior view but broader and U-shaped in
posterior view (Fig. 8A–B). The pedicel width is equivalent to the
neural canal at mid-level of the neural canal, where it is broken
dorsally. The pedicels reach the posteriormost facet of the
centrum. The general surface of the bone is lustrous in the lateral
and ventral surface of the centrum, but matt on the posterior facet.
If complete, the centrum would be moderately excavated, giving a
hourglass outline in ventral view.
Phylogenetic Analysis
ML 1100 was previously assigned to Torvosaurus tanneri by
Mateus et al. [4] based on an antorbital tooth row, the absence of
a maxillary fenestra (antorbital foramen of [4]) and pneumatisa-
tion on the ascending ramus, and the posterior orientation of the
ascending ramus of the maxilla. In order to confirm the
phylogenetic affinities of this specimen, a cladistic analysis was
performed using the datamatrix of Carrano et al. [61]), the most
recent and exhaustive analysis focusing on relationships of basal
Tetanurae. The datamatrix includes 60 ingroup taxa and two
outgroups (Eoraptor and Herrerasaurus) coded in 353 unordered and
equally weighted characters [61]. Following personal observation
of the maxilla in basal tetanurans, one character was modified
from Carrano et al. [61] and two additional characters were
created (see Text S1). A total of 36 characters were coded for the
maxilla, two for the interdental plates, nine for the dentition and
one for the caudal vertebra. TNT v1.1 [98] was employed to
search for most-parsimonious trees (MPTs). As a first step, the
matrix was analysed under the ‘New Technology search’ with the
‘driven search’ option, TreeDrift, Tree Fusing, Ratchet, and
Sectorial Searches selected with default parameters, and stabilizing
the consensus twice with a factor of 75. The generated trees were
then analysed under traditional TBR (tree bisection and recon-
nection) branch [98]. Bremer support [99] and Reduced Cladistic
Consensus Support Trees [100] were calculated with TNT by
saving 10,000 suboptimal trees up to 10 steps longer than the
MPTs. The consistency and retention indexes as well as the
Bremer and relative Bremer supports were calculated using the
‘‘stats’’ and the ‘‘aquickie’’ commands, respectively.
The cladistic analysis yielded 93 MPTs, 1033 length, with a
consistency index of 0.404 and a retention index of 0.677 for the
strict consensus tree. The tree mirrors to a large degree the
topology obtained by Carrano et al. [61]) and retrieved ML 1100
and Torvosaurus tanneri as sister taxa. The clade of Megalosauria
[61] was however badly resolved and a reduced consensus
approach [100–102] was used by excluding a posteriori four
wildcard taxa with a lot of missing data (Magnosaurus,Poekilopleuron,
Streptospondylus and Xuanhanosaurus). The topology of the resulting
consensus tree is similar to the consensus tree obtained when
excluding a priori the four taxa (Fig. 9), and the tree displays a few
polytomies, mostly in the clade of Megalosauridae and Carchar-
odontosaurinae. Nevertheless, all major clades of Tetanurae were
found resolved and the Torvosaurus taxa are still closely related,
forming the sister clade of the taxon Megalosaurus (Fig. 9). Following
the result of the cladistic analysis, ML 1100 can confidently be
assigned to the taxon Torvosaurus. The maxilla ML 1100 indeed
belongs to a theropod based on the combination of a subnarial
foramen and very large ziphodont teeth bearing coarse denticles, a
tetanuran due to its anteroposteriorly long anterior ramus, the
presence of a maxillary recess (i.e., either a maxillary fenestra or a
maxillary fossa) within the lateral antorbital fossa, and a tooth row
extending anterior to the orbit. In also pertain to a megalosaurid
by the presence of a maxillary fossa, to the clade encompassing
Megalosaurus and Torvosaurus by the tall interdental plates
(ventrodorsal depth relative to the anteroposterior width .1.8
[61]), and to the Torvosaurus by the shallow maxillary fossa, limited
Table 3. Number of denticles in maxillary teeth of the
holotype of Torvosaurus gurneyi (ML 1100).
Denticles (per 5 mm)
Second erupted maxillary tooth
Mesioapical denticles (MA) 6
Mesial denticles at mid-height (MC) 8
Mesiobasal denticles (MB) /
Distoapical denticles (DA) 7
Denticles at mid-height (DC) 8
Distobasal denticles (DB) 11
Third unerupted maxillary tooth
Mesioapical denticles (MA) 6
Mesial denticles at mid-height (MC) 7
Mesiobasal denticles (MB) /
Distoapical denticles (DA) 6
Denticles at mid-height (DC) 8
Distobasal denticles (DB) 10
doi:10.1371/journal.pone.0088905.t003
Torvosaurus from Portugal
PLOS ONE | www.plosone.org 15 March 2014 | Volume 9 | Issue 3 | e88905
Table 4. Measurements of proximal caudal vertebra of the holotype of Torvosaurus gurneyi (ML 1100).
Measurements (mm)
Dorsoventral height of centrum at the level of the neural canal: 129
Dorsoventral height of centrum at its maximum height: 145
Transverse width of centrum: 121
Anteroposterior length of centrum: 52
doi:10.1371/journal.pone.0088905.t004
Figure 9. Cladogram of basal Theropoda and phylogenetic position of
Torvosaurus gurneyi
.Strict consensus cladogram from 71 most
parsimonious trees after pruning Magnosaurus,Poekilopleuron,Streptospondylus and Xuanhanosaurus from the full set of most parsimonious trees.
Initial analysis used New Technology Search using TNT v.1.1 of a data matrix comprising 353 characters for two outgroup (Eoraptor and Herrerasaurus)
and 60 nonavian theropod taxa. Tree length = 1022 steps; CI = 0.414, RI = 0.685. Bremer support values are in regular and bootstrap values are in bold.
Dinosaur silhouettes by Scott Hartman (all but Metriacanthosauridae; used with permission) and Gregory S. Paul (Metriacanthosauridae; used with
permission).
doi:10.1371/journal.pone.0088905.g009
Torvosaurus from Portugal
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ventral extension of the lateral antorbital fossa on the maxillary
body, and fused interdental plates forming an interdental wall
[61].
Discussion
The maxillae of ML 1100 and the referred specimen of T. tanneri
BYU-VP 9122 share striking similarities (Fig. 10). Not only their
anatomy is very close but they also share similar size and angles of
rami. Many other features are common between ML 1100 and
BYU-VP 9122, namely, large and elongated teeth with coarse
denticles (8 denticles per 5 mm or less), a shallow subtriangular
maxillary fossa at the base of the ascending ramus, an ascending
ramus angled at 30ufrom the ventral margin, an anteroposteriorly
oriented ridge ventral to the shallow maxillary fossa within the
lateral antorbital fossa, and very tall fused interdental plates that
are perforated by large nutrient foramina at the level of the
nutrient groove. Therefore, the Portuguese specimen clearly
belongs to the taxon Torvosaurus first described from the
Kimmeridgian-Tithonian of North America [91]. The two taxa
also share similar stratigraphical range as the Portuguese specimen
is late Kimmeridgian in age, and its American counterpart has
been recorded in late Kimmeridgian to late Tithonian deposits
[61]. Nevertheless, they were geographically separated by
thousands of kilometres and the proto Atlantic epicontinental sea
was restraining the European Torvosaurus to the Iberian Meseta
[21]. If the assignation of ML 1100 to Torvosaurus is hardly
doubtable, it is legitimate to assess its affiliation to the species T.
tanneri given the paleogeographical context.
A detailed comparison of ML 1100 with BYU-VP 9122 (and
ML 1186, a cast of BYU-VP 9122 deposited at the Museu of
Lourinha˜) allows highlighting some differences between the two
maxillae (Figs. 6–7I–L, 10). One of the most notable was observed
by Mateus et al. [4] and concerns the maxillary tooth count.
Eleven alveoli have been noticed by Britt [27] for BYU-VP 9122
and, according to this author, there were up to 12 or 13 maxillary
teeth based on the intersection of the medial wall and ventral
margin. On the other hand, the Portuguese specimen possesses
eight maxillary alveoli, with a maximum number of ten teeth [4].
Although maxillary alveoli gradually decrease in size in theropods,
the spacing between them remains the same (pers. obs.). In
megalosauroids, the last alveoli never occupy less than 50% of the
size of the largest alveoli (pers. obs.), so that the presence of more
than two alveoli in the missing section of the jugal ramus is very
unlikely, and there were almost certainly no more than ten teeth in
ML 1100. Examination of ML 1186 does not clearly reveal the
presence of an eleventh alveoli, and only ten alveoli, with nine
complete and the posteriormost one incomplete, could only be
observed. Based on the posterior intersection of the boundary
between the interdental wall and the ventral margin, we evaluate
the total number of alveoli to eleven or twelve in T. tanneri. This
therefore corresponds to a slightly closer tooth count of BYU-VP
9122 from ML 1100. Although tooth count is commonly used for
taxonomic purpose by many authors in nonavian theropods (e.g.
[6,39,41,61,62]), variation in the number of maxillary alveoli
occurs through ontogeny (e.g., [13,48]), between individuals of the
same species (e.g., [46,53,103,104]), and even between left and
right maxillae of a same specimen (e.g., [32,104,105]). Tooth
count should therefore be cautiously employed for synapomorphic
purpose. Nevertheless, it is interesting to highlight that ML 1100 is
the only megalosauroid possessing fewer than eleven teeth on the
maxilla and, with the exception of the toothless ceratosaur
Limusaurus [106] and the primitive theropod Daemonosaurus [107],
the only non-coelurosaurian theropod with such a feature (pers.
obs.). The maxilla of Noasaurus, interpreted as having 10 to 11
maxillary teeth by [108], in fact possesses 12 to 13 alveoli (pers.
obs.).
Another difference between the American and European
specimens is the ventral extension of the interdental plates relative
to the lateral wall as well as the morphology of the ventral
terminations of the interdental plates (Fig. 5–6I–J). In ML 1100,
the interdental plates extend almost as far ventral as the lateral
wall, whereas the interdental plates of T. tanneri fall short and end
well dorsal of the lateral wall of the maxillary body. This later
feature is considered to be a synapomorphical character of the
clade encompassing Torvosaurus and Megalosaurus by Benson [41]
and Carrano et al. [61]. It can also be observed in other theropods
such as the tyrannosauroids Guanlong,Daspletosaurus and Tyranno-
saurus and the allosauroids Allosaurus and Neovenator (see Table S1;
pers. obs.). Britt [27] remarked that this character may be due to
crushing but examination of ML 1186 seems to reveal that the
interdental plates genuinely end well dorsal to the lateral wall of
the maxilla. Nonetheless, it is difficult to know whether this feature
can variate ontogenetically, intraspecifically or can genuinely
distinguish two taxa. Based on very large and similar size of their
maxillae, ML 1100 and BYU-VP 9122 clearly belong to animals
of the same size and ontogenetic stage, and most likely fully adult
individuals of more than nine meters (see below), so that
ontogenetic variation cannot be taken into consideration. The
maxillae of the different specimens of Dilophosaurus wetherilli
(UCMP 37303, TMM 43646-1; Fig. S1), Ceratosaurus nasicornis
(UMNH VP 5278; MWC 1), Majungasaurus crenatissimus (FMNH
PR 2100, 2278), Marshosaurus bicentesimus (UMNH VP 7824, 7825;
CMNH 21704), Megalosaurus bucklandii (BMNH R.8303; OUMNH
J13506, 13559), Allosaurus fragilis (AMNH 600, 851; BYU-VP
2008; UMNH VP 5393, 9168, USNM 8335) and Tyrannosaurus rex
(CMNH 9380; FMNH PR 2081; BHI 3033) all show similar
ventral extension of the interdental plates. On the other hand, the
two species of Carcharodontosaurus,C. saharicus (SGM Din–1) and C.
iguidensis (MNN IGU2) can be differentiated on this aspect as the
interdental plates of the former extend more ventral than the latter
(pers. obs.). Based on this observation, the ventral extension of the
interdental plate relative to the lateral wall may genuinely variate
interspecifically and this feature is therefore considered to be a
synapomorphical character differentiating the two species of
Torvosaurus. To our knowledge, the presence of an interdental
wall coincidental with the lateral wall of the maxillary body is an
autapomorphical feature of T. gurneyi among Megalosauroidea.
As noted by Britt ([27]:17), the interdental plates of the maxilla
also ‘‘terminate ventrally in broad, V-shaped points’’ in BYU-VP
9122 (Fig. 5J). On the contrary, the ventral rim of the interdental
plates are straight and continuous all along the interdental wall in
ML 1100 (Fig. 5I). A V-shaped margin of the interdental plates is
common among theropods and can be observed in the noasaurid
Masiakasaurus, the abelisaurids Rugops and Indosuchus, the mega-
losauroids Marshosaurus,Piatnitzkysaurus,Eustreptospondylus,Duriave-
nator and Afrovenator, the allosauroids Allosaurus,Neovenator,Sinraptor
and Mapusaurus, and the tyrannosaurids Alioramus,Tarbosaurus and
Tyrannosaurus (see Table S1). Subrectangular interdental plates can
however be seen in the ceratosaurs Ceratosaurus,Noasaurus,
Aucasaurus and Majungasaurus, the megalosaurid Megalosaurus, the
allosauroid Shaochilong, and the tyrannosauroid Eotyrannus (pers.
obs.; Table S1). Variation in the ventral margin of the interdental
plates does not seem to occur among mature individuals of the
same species, with perhaps the exception of Mapusaurus in which
the V-shaped of the interdental plates seems to be much more
pronounced in MCF-PVPH-108.169 than in MCF-PVPH-
108.115 ([34]:fig. 2B–D). However, anterior interdental plates
Torvosaurus from Portugal
PLOS ONE | www.plosone.org 17 March 2014 | Volume 9 | Issue 3 | e88905
are badly preserved in MCF-PVPH-108.115 and the posterior
ones show the distinct V-shaped condition (pers. obs.). A similar
variation also exists in the two species of Carcharodontosaurus (pers.
obs.). In C. iguidensis, the ventral margin of the fused interdental
plates are clearly V-shaped whereas in C. saharicus, although many
of them are not intact, the plates tend to have a much straighter
ventral margin. Surprisingly, in Dilophosaurus wetherilli the mor-
phology of the interdental plates differ significantly between the
Figure 10. Comparison of the maxillae of
Torvosaurus gurneyi
and
Torvosaurus tanneri
.Left maxillae of the holotype specimen of
Torvosaurus gurneyi (ML 1100) in A, lateral; B, medial; E, ventral; F, dorsal; I, anterior; and K, posterior views. Left maxillae of a specimen referred to
Torvosaurus tanneri (BYUVP 9122) in C, lateral; D, medial; G, ventral; H, dorsal; J, anterior; and L, posterior views. Abbreviations: adc, anterodorsal
crest; adr, anterodorsal ridge of the anteromedial process; afo, anterior foramina; al1, first alveolus; al8, eighth alveolus; al10, tenth alveolus; amp,
anteromedial process; aor, antorbital ridge; avg, anteroventral groove of the anteromedial process; avr, anteroventral ridge on the anteromedial
process; idw, interdental wall; ldr, laterodorsal ridge within the anterior corner of the lateral antorbital fossa; mfo, maxillary fossa; nuf, nutrient
foramina; nug, nutrient groove; nvo, neurovascular opening. Scale bars = 5 cm.
doi:10.1371/journal.pone.0088905.g010
Torvosaurus from Portugal
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youngest juvenile TMM 43646-1, the adult specimen UCMP
77270 and the immature individuals UCMP 37302 (holotype) and
37303 (paratype; [42]:fig. 36; see File S1). In TMM 43646-1 and
UCMP 77270, the plates are separated, subquadrangular to
vertical subrectangular and the ventral margin is clearly V-shaped
whereas the type specimens possess fused interdental plates that
are horizontally rectangular with a straight ventral margin (Fig.
S1). Whether fusion and variation in the interdental plates
morphology may occur throughout ontogeny, such intraspecific
variability of the interdental plates seems very unlikely and we
therefore estimates that TMM 43646-1 and UCMP 77270 may
represent a different taxon of Dilophosaurus wetherilli, as it was
already suggested ([83]; see File S1). We therefore consider the
straight ventral margin of the interdental plates as a potential
synapomorphical character of the clade encompassing Megalo-
saurus+Torvosaurus (under ACCTRAN optimization), and interden-
tal plates with V-shaped ventral margin are therefore the
plesiomorphic condition in tetanurans and megalosauroids.
The morphology of the medial wall and the anteromedial
process also differ between the American and European
Torvosaurus (Figs. 5–6K–L). BYU-VP 9122 displays a protruding
ridge corresponding to the anterior part of the medial shelf
(Fig. 5L). It extends from the posterodorsal part of the
anteromedial process and gets flared to the level of alveolus 4.
This ridge is absent from ML 1100 where only a low and wide
anteroposteriorly oriented convexity corresponding to the anterior
part of the medial shelf is observable (Fig. 5K). The medial shelf of
the jugal ramus is more prominent in T. tanneri than in ML 1100
but the latter displays a low crest centrally positioned on the
medial shelf, a feature absent in BYU-VP 9122. The ventral ridge
of the anteromedial process also extends more anterior than the
dorsal one, and only to the level of the second alveolus in BYU-VP
9122. On the other hand, the two main ridges of the anteromedial
process of ML 1100 get flared at the same level posteriorly. In
Megalosauroidea, this condition is shared with Marshosaurus,
Piatnitzkysaurus,Eustreptospondylus,Afrovenator and Megalosaurus
whereas in Duriavenator,Dubreuillosaurus the dorsal ridge of the
anteromedial process extends further posteriorly than the ventral
one (pers. obs.). Likewise, the groove delimited by the two ridges of
the anteromedial process is notably wider in BYU-VP 9122 than
in ML 1100. Furthermore, the posterior nutrient foramina are
conspicuously larger in BYU-VP 9122 and, in this specimen, the
anterior rim of the maxillary body is more inclined posteriorly, the
anterior part of the ventral margin smoothly curves dorsally, and
the parabolic outline of the antorbital fenestra is ventrodorsally
wider. Again, it is difficult to know whether these differences
between the American and European specimens exist inter- or
intraspecifically, but some of them can certainly be considered as
intraspecific variations.
As noted, some anatomical differences can be observed between
ML 1100 and BYU-VP 9122, mostly in the morphology of the
medial shelf and interdental plates. The presence of fused
interdental plates forming a wall coinciding with the lateral wall
of the maxilla is an autapomorphical character of ML 1100 among
megalosauroids and, to our knowledge, this feature does not vary
intraspecifically. Likewise, the protruding ridge posterior to the
anteromedial process of BYU-VP 9122 seems to be an
autapomorphy of Torvosaurus tanneri among non-coelurosaurs
theropods, and the absence of this feature in ML 1100 supports
its affiliation to a different taxon. Finally, the geographical context
of the European specimen of Torvosaurus, which seems to have
been isolated on the Iberian Meseta in the Kimmeridgian [21],
favours this option, and we therefore refer the Portuguese
specimen to a new species of Torvosaurus,Torvosaurus gurneyi.
Torvosaurus gurneyi provides additional information on the
maxilla anatomy of Torvosaurus. The dorsal margin of the
ascending ramus is smoothly convex and the anterodorsal rim of
the ascending ramus makes a step at two thirds of the process so
that the ventral part of the ascending ramus tapers posteriorly.
There is a small convexity on the dorsal margin of the jugal ramus,
at two thirds of it, where the lacrimal articulates with the maxilla
medially. Likewise, the lacrimal articulation of the maxilla
corresponds to a deep slit within the jugal ramus. The presence
of a neurovascular opening penetrating the maxilla on the
dorsomedial margin of the jugal ramus, at the level of the eighth
alveolus, can also be noted and represents an autapomorphy for
the taxon Torvosaurus. This opening is also present in BYU-VP
9122 but not well visible due to crushing so that Britt [27] did not
mention it.
Size and Paleogeographical Implications
With a minimum length of 612 mm, the maxilla of Torvosaurus
gurneyi pertains to a very large individual positioned at the apex of
the food chain in the Late Jurassic ecosystem of Iberia. The
maxilla occupies 52% (Allosaurus) to 61% (Yangchuanosaurus) of the
skull length in the largest avetheropods belonging to the clade of
Ceratosauria, Megalosauroidea, Allosauroidea and Tyrannosaur-
oidea), 53% being the proportion of the maxilla in the closely
related basal tetanurans Sciurumimus and Monolophosaurus. Following
this tendency, we can estimate the skull length of Torvosaurus to
approximately 115 cm (Fig. 4B), lower than what was proposed by
Mateus et al. [4]. Torvosaurus was therefore not competing in size
with the largest theropod Tyrannosaurus (maxilla length of
,750 mm in CMNH 9380), Carcharodontosaurus (.710 mm in
SGM Din-1) or Giganotosaurus (.680 mm in MUCPv-CH-1) but
likely had a similar size than the tyrannosaurids Daspletosaurus,
Gorgosaurus and Tarbosaurus [109] from the Cretaceous. Nonethe-
less, with a body length of around 10 meters (Fig. 4A) and a weight
of approximately 4 to 5 tons (estimations based on [109]),
Torvosaurus gurneyi represents the largest theropod from the
Lourinha˜ Formation of Portugal, one of the largest land predators
of the Jurassic, and the largest terrestrial predator discovered in
Europe hitherto.
Torvosaurus occurrences are restricted to the Late Jurassic of
Morrison and Lourinha˜ Formations, in United States and
Portugal, respectively. The Portuguese form, T. gurneyi, is Late
Kimmeridgian in age based on strontium and biostratigraphy
[110]. The holotype specimen of T. tanneri is from Dry Mesa
(Brushy Basin Member) which has been placed in the Late
Kimmeridgian ([111]:1466), but the isotopic dates are still within
the Early Tithonian in the new chronostratigraphic dates of ICS
International Commission on Stratigraphy (www.stratigraphy.
com) for the Late Jurassic.
The closest relative of the genus Torvosaurus is likely to be the
European Bathonian Megalosaurus ([41,61]), therefore the lineage
leading to the genus likely originated during or around the
Bathonian. At this time, the proto-Atlantic sea was well formed as
demonstrated by ammonites and other sea fauna in the Portuguese
west margin since the Early Jurassic. Therefore, the North
American/European passage was already limited for terrestrial
vertebrates well before the cladogenesis of Megalosaurus/Torvosaurus
or T. tanneri/T. gurneyi. However, as suggested by Mateus et al.
[21], the passage of Torvosaurus and other genera between North
America and the Iberian Meseta may have happened during the
temporary short-duration regional uplift around the Callovian/
Oxfordian transition (ca. 163.5 Ma) that created the temporary
opportunity of land gateways in the proto-Atlantic. The isolation
of the Iberian block after that temporary uplift leaded to an
Torvosaurus from Portugal
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important vicariance during nearly 10 My until the occurrence of
many Laurasian taxa such as Torvosaurus in the Late Kimmer-
idgian. This pattern of occurrences shared by Morrison and
Lourinha˜ Formations is also corroborated with the presence of
other common genera, Allosaurus,Ceratosaurus,Stegosaurus,Dryo-
saurus, and related sister-taxa. This timing of vicariance also
explains why the two regions have vertebrate faunas that are
generically similar but specifically different. Finally, the true
oceanization, with oceanic crust, of that section of North-Atlantic
started during the Early Cretaceous.
Other Occurrences of Torvosaurus in Portugal
Cranial bones. The anterior part of a right maxilla (ALT-
SHN.116) discovered in the Lourinha˜ Formation of Praia da
Corva (Torres Vedras) was described and referred to the taxon
Torvosaurus sp. by Malafaia et al. [8]. The fragment of maxilla
consists of an incomplete portion of the antorbital body and the
anteroventral part of the ascending ramus [8]. The anterior part of
the anterior ramus as well as the posterior portion of the antorbital
body are missing, and both alveolar and dorsal margins of the
antorbital body are strongly damaged. In lateral view, the
anteriormost part of the lateral antorbital fossa has been preserved
and is delimited by the antorbital ridge that bounds a depression
filled with sediment laterally [8]. Two large maxillary alveolar
foramina and one medium alveolar foramen are present at the
level of what we interpret to be the fourth alveolus, just dorsal to
the ventral margin of the maxilla. Only one small maxillary
circumfenestra foramen seems to be preserved dorsal to the
posteriormost alveolar foramen. As noted by Malafaia et al. [8],
the lateral surface of the maxilla is smooth rather than rugose. In
medial view, only the posterior part of the anteromedial process is
preserved and displays two parallel ridges running longitudinally
on the medial side of the process. The groove delimited by these
two ridges is broad and shallow. The interdental plates are not
well-preserved but are tall and clearly fused, and their surface
seems to be striated by parallel grooves running ventrodorsally.
The medial shelf is ventrodorsally broad but poorly protuberant,
and its main axis is oriented posteroventrally. The nutrient groove
is visible but not clearly marked, and two large nutrient foramina,
likely of the second and fourth alveoli, are present at the level of
this groove. Dorsomedially, the nasal contact is broad and not
visible laterally [8]. An unerupted tooth can be seen throughout a
small fracture and its mesial carina bears around 10 denticles per
5 mm [8].
This fragment of maxilla was assigned to Torvosaurus sp. by
Malafaia et al. [8] based on the absence of a maxillary fenestra
between the antorbital fenestra and the nasal contact, and the
shape and position of the antorbital ridge bounding the antorbital
fenestra anteroventrally [8]. We agree with the assignment of this
fragment to Torvosaurus but for different reasons. The presence (or
absence) of a maxillary fenestra/fossa cannot be determined due to
the fact that most of the anterior corner of the lateral antorbital
fossa and the posteroventral portion of the ascending process are
not preserved. The maxillary sinus are always located in this area
in all basal theropods, including Torvosaurus, and the presence of a
maxillary fenestra cannot therefore be ruled out. In fact, the
shallow maxillary fossa diagnostic of Torvosaurus tanneri [27] is not
preserved in ALT-SHN.116, and what has been interpreted as the
anteriormost rim of the antorbital fenestra by Malafaia et al.
([8]:fig. 2B1) is, in fact, a diagnostic ridge located on the
anteriormost corner of the lateral antorbital fossa (pers. obs.).
Likewise, an antorbital ridge forming a lateral rim that bounds a
recess within the anteriormost corner of the lateral antorbital fossa
is a feature shared by a few basal theropods such as Ceratosaurus,
Torvosaurus,Afrovenator and Dubreuillosaurus (pers. obs.). As correctly
noticed by Malafaia et al. [8], an antorbital ridge located just
below the antorbital fenestra in the anteroventral part of the lateral
antorbital fossa is indeed present in Torvosaurus, but equally shared
by abelisaurids, Monolophosaurus and Eustreptospondylus (pers. obs.).
However, the rim of the antorbital fenestra is not preserved in
ALT-SHN.116, and the position of the antorbital ridge relative to
the antorbital fenestra cannot therefore be used as a diagnostic
feature. Nonetheless, this fragment of maxilla includes several
important features that support affinities with the genus Torvo-
saurus. ALT-SHN.116 belongs to tetanurans given the presence of
a moderately (or strongly) elongated anterior ramus, to Mega-
losauria or Allosauria (as proposed by [61]) due to the position of
the anteromedial process, immediately ventral to the dorsal surface
of the anterior ramus [61], to the clade including Torvosaurus and
Megalosaurus because of the tall interdental plates and to Torvosaurus
by the presence of fully fused interdental plates [61] and a
prominent anteroposteriorly oriented ridge (different from the
antorbital ridge) in the anteriormost corner of the lateral antorbital
fossa, an autapomorphy of Torvosaurus (pers. obs.). ALT-SHN.116
can be even assigned to the new taxon Torvosaurus gurneyi by the
presence of interdental plates extending to the same level than the
lateral wall, the straight ventral margin of interdental plates
(absence of V-shape interdental plates), two longitudinal ridges of
the anteromedial process that get flared at the same level
posteriorly, and the absence of a prominent ridge posterior to
the anteromedial process. ALT-SHN.116 can therefore be
referred to Torvosaurus gurneyi with confidence.
A mesialmost tooth (ML 962) from the Early Tithonian of the
Lourinha˜ Formation in Praia da Area Branca (Lourinha˜) was
recently identify to belong to Torvosaurus tanneri [6] based on size
(CH .80 mm), crown elongation (CHR of 2.7), large denticles
(,8 denticles per 5 mm on both carinae), outline of the cross-
section (CBR of 0.64) and position and basal extension of the
mesial carina ([6]: fig.9). Given the fact that ML 962 and T. gurneyi
have close paleogeographical and stratigraphical distributions, we
tentatively assign the tooth to the Portuguese species of Torvosaurus.
A large tooth (FUB PB Ther 1) discovered in the Late
Kimmeridgian of the Lourinha˜ Formation (Sobral Member = -
Praia Azul Member sensu [112]) in Porto das Barcas was ascribed
to an indeterminate Carnosauria by Rauhut & Kriwet [113] based
of large size and interdenticular sulci. A discriminant analysis used
by [114] classified it as Ceratosaurus although the authors admitted
that this analysis ‘‘cannot provide a genus-level classification for a
tooth that came from a taxon for which there are no data in the
standard’’ ([114], p. 715). A better understanding of theropod
dentition, as well as morphometric data collected in the dentition
of Torvosaurus, allows us to confidently refer this lateral tooth to this
taxon, and tentatively to T. gurneyi given the stratigraphic and
geographic contexts. Indeed, FUB PB Ther 1 shares a combina-
tion of features only seen in Torvosaurus lateral teeth such as a large
(CH = 80 mm) moderately labiolingually compressed (CBR of
0.53) crown bearing large and coarse denticles (6.5 denticles/
5 mm on both carinae), well-developed interdenticular sulci, a
clearly-visible braided enamel texture, and a mesial carina
centrally positioned on the crown (not offset or twisted) and
extending on the apical half of the crown. Large teeth of eight
centimetres or more are only borne by ceratosaurids, non-
coelurosaur tetanurans and tyrannosauroids, and lateral teeth
with very large denticles (,8 denticles/5 mm) by Megalosauridae,
Carcharodontosaurinae, and Tyrannosauridae (pers. obs.). Tyr-
annosaurid teeth are distinctly incrassate (CBR.0.55), and the
mesial carina of carcharodontosaurine and Ceratosaurus teeth either
reaches the cervix or extend just above it (pers. obs.). Among
Torvosaurus from Portugal
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Megalosauridae, large crowns with very well-developed inter-
denticular sulci and marked enamel texture are, to our knowledge,
a combination of features only existing in Torvosaurus. Further-
more, the latter is the only megalosaurid theropod from the Late
Jurassic of Portugal.
Postcranial bones. The distal portion of a right femur (ML
632; Fig. 11A–G) from Cadaval (Quinta do Gradil) has been
briefly reported by [4] and tentatively assigned to Torvosaurus based
on its large size. The femur preserves the distal diaphysis, which
includes two partially damaged condyles, and a portion of the shaft
is preserved to the proximal extension of the mesiodistal crest. The
bone is massive, the proximo-distal length of the distal portion
measuring more than 370 mm (Table 5), and one can estimate the
total length of the whole bone to around 1110 mm based on the
length and proportion of the femur of Megalosaurus bucklandii
(BMNH 31806; [41]). The minimum circumference of the shaft is
370 mm at the level of the break and its transversal ratio
(lateromedial width/anteroposterior width) is 1.44.
The shaft expands mediolaterally towards the distal diaphysis
and gives rise to two condyles separated by the extensor groove
anteriorly (Fig. 11A) and the flexor groove posteriorly (Fig. 11D).
The medial condyle is anteroposteriorly longer than the lateral one
and elliptical in outline in distal view (160 mm long by 80 mm wide
at its midpoint; Table 5) with its long axis directed posterolaterally
(Fig. 11G). Fragments of the laterodistal, mesiodistal and posterior
surface of the medial condyle are missing so that it is not possible to
know the proximal extension of the articulating surface posteriorly.
This surface is, however, well-preserved anteriorly and extends
further proximally than in the lateral condyle. The medial margin of
the medial condyle corresponds to a planar surface bearing a
shallow concavity centrally positioned on its distal most part. The
medial margin of the diaphysis displays many shallow striations
extending along 190 mm of the medial side of the femur posteriorly
(Fig. 11E). The posterior margin of the medial condyle is strongly
convex, forming a large protuberance delimiting the flexor groove
medially. The latter is lateromedially large (40 mm width) and
extends along 120 mm of the bone surface, keeping the same width
proximo-distally. The floor of the flexor groove is flat and grooved
on its medial part, and the larger sulcus penetrates the bone on the
proximomedial corner of the flexor groove.
The lateral condyle is roughly D-shaped (100 mm anteropos-
terioly by 105 mm lateromedially), with the concavity facing
Figure 11. Femur and tibia of Megalosauridae from the Late Jurassic of Portugal. Distal portion of a left femur (ML 632) of a megalosaurid
tentatively referred to Torvosaurus gurneyi in A, anterior; B, lateral; C, posterior; D, medial; E, proximal; and F, distal views. Incomplete left tibia (ML
430) of Torvosaurus sp. (and tentatively referred to Torvosaurus gurneyi), with reconstruction of missing part of cnemial crest, in A, anterior; B, lateral;
C, posterior; D, medial; E, proximal; and F, distal views. Abbreviations: asc, contact with astragalus; ccr, cnemial crest ridge; cnc, basal part of cnemial
crest; ctf, crista tibiofibularis; dep, anterodistal depression; dir, distal ridges; exg, extensor groove; ffl, fibular flange; flg, flexor groove; lc, lateral
condyle; mc, medial condyle; mdc, medio-distal crest; sab, supracetabular buttress. Scale bars = 10 cm.
doi:10.1371/journal.pone.0088905.g011
Torvosaurus from Portugal
PLOS ONE | www.plosone.org 21 March 2014 | Volume 9 | Issue 3 | e88905
anteriorly (Fig. 11G). The condyle projects posteromedially to
form the crista tibiofibularis in which most of the posterior portion
is missing (Fig. 11B). The crista tibiofibularis corresponds to a large
crest of 55 mm in width in its posteriormost part, and extends
proximo-distally along 130 mm of the lateral surface of the femur.
The crest tapers proximally and curves proximo-laterally so that
the medial margin of the crista tibiofibularis is convex whereas the
lateral surface is weakly concave. This surface is also deeply
striated by radiating grooves converging proximally. The posterior
margin of the lateral condyle is shallowly concave and weakly
grooved, in contrast to its lateral and anterior surfaces which,
together, form a wide convexity. The latter is covered by large,
deep and well-developed parallel striations in which the longest
extend along 65 mm of the bone. The largest and deepest grooves
are located on the anterolateral margins of the lateral condyles and
show a strong attachment of the disto-femoral muscles (Fig. 11B).
The anterodistal surface of the femur is deeply excavated by the
extensor groove which is narrower and deeper than the flexor
groove (Fig. 11A). The extensor groove corresponds to a shallow
depression in its proximal part and a deep fossa more distally,
having a width of 20 mm in its distalmost part. The anterior
surface of the femur displays a massive medial distal crest can-
shaped in outline (or a reversed J) and extending from above the
medial condyle along 190 mm of the shaft (Fig. 11A). The medial
distal crest is poorly delimited laterally and bounded by a short
elevation of the shaft proximally. A wide depression, bounded by
the medial distal crest laterally, occupies the central part of the
anterodistal surface of the femur. This large concavity has a rugose
surface proximo-laterally, just medial to the medio-distal crest, and
merges with the extensor groove distally (Fig. 11A).
The femur is tentatively referred to Torvosaurus gurneyi based on
its size, paleogeographic and stratigraphic distributions, and a
combination of features only seen in derived megalosaurids. ML
632 belongs to Orionides based on the presence of an extensor
groove anteriorly, to Megalosauroidea due to the absence of a
large depression on the anterodistal surface of the mesial condyle
of the distal diaphysis (the rugose depression that exists on the
anterior surface of the medial condyle in coelophysoids, cerato-
saurs and allosauroids cannot be confused with the centrally
positioned depression on the anterodistal surface of ML 632), and
to Megalosauria based on the longitudinal and narrow tibiofibu-
laris crest [61]. Among Megalosauria, the protuberant medial
distal crest running on the anterodistal surface of the femur is
absent in Spinosauridae and some megalosaurids such as
Eustreptospondylus and Leshansaurus. It is poorly developed in
Megalosaurus [41], and only well-developed and protuberant in
the femur TATE 0012 ([95]:fig. 16B), a specimen of large
megalosaurid of the Morrison Formation [95] referred to
Torvosaurus tanneri [61]. Furthermore, the distal diaphysis bears
large and deep striations on its anterior, lateral and medial surface,
a condition shared with TATE 0012 ([92]:fig. 16). As for TATE
0012, ML 632 is tentatively assigned to Torvosaurus. It however
differs from TATE 0012 by a long axis of the medial condyle
directed posterolateral in distal view (a condition shared with
Baryonychinae [61]), a much deeper extensor groove, and a long
axis of the medial distal crest directed proximo-distally (like in
Megalosaurus) rather than proximo-laterally ([95]:fig. 16B). In fact, a
posterolateral orientation of the mediodistal condyle as well as a
prominent medial distal crest curving proximo-laterally and
delimiting a large concavity medially, seem to be two autapomor-
phies of ML 632 among Megalosauridae (pers. obs.). The femur
comes from a different site than the type specimen of T. gurneyi and
cannot be assigned to this taxon as the latter did not preserve any
limb bones. Nevertheless, given the geographic and stratigraphic
position of ML 632 and the numerous features shared with TATE
0012, it is likely that the bone belongs to Torvosaurus gurneyi.
However, this referral has to be regarded as tentative, pending
detailed description and analysis of TATE 0012.
With a lateromedial width of 235 mm for the distal diaphysis and
an approximate length of 1100 mm for the femur (Table 5), ML
632 pertains to an animal of around 3 to 4 tons, for a body length of
around 10 meters (estimations based on [109] and [115]).
A large sized left tibia (ML 430; Fig. 11H–M) from Casal do
Bicho was the first bone unequivocally ascribed to Torvosaurus in
Portugal [7]. The tibia has a unique character combination that
allows a generic identification, as recognized since Britt [27],
including the high diaphyseal perimeter/length ratio, low astrag-
alar contact surface and short and round cnemial crest. With a
total length of 820 mm and a minimum circumference of 385 mm
(Table 5), ML 430 pertained to a slightly bigger animal than BYU
VP 2016 (length of 725 mm, min. circ. of 327 [27]) that should
have had a body mass of around 1.6 to 1.7 tons for a body length
of around 7 meters (estimation based on [109] and [115]). Given
its paleogeographic and stratigraphic distributions and a combi-
nation of features only existing in Torvosaurus tibiae, ML 430 is
tentatively referred to Torvosaurus gurneyi.
Tracks. Only in rare cases in vertebrate paleontology, one
can establish a connection between a track and a genus of species
of trackmaker. However, in Portugal there are no other theropod
that could rivalize Torvosaurus in size, and produce such large tracks
as the ones from the beds of Porto Dinheiro (ML 2035, [116]:fig.
9). Being 79 cm long and 60 cm wide, ML 2035 is one of the
largest theropod tracks known from the Jurassic. These tracks
found at the base of Sobral Member of Lourinha˜ Formation are
dated as Late Kimmeridgian, just as the Torvosaurus bones from
Portugal. Nevertheless, due to the absence of clear pedal
autapomorphies that are recognizable in Torvosaurus tracks, the
trackmaker of ML 2035 is tentatively referred to Torvosaurus.
Embryos. Arau´jo et al. [9] recently reported an incomplete
right maxilla and dentary and three centra of a single or several
Torvosaurus embryos (ML 1188:fig. 9A–F) from the Late Kimmer-
Table 5. Measurements of limb bones tentatively referred to
Torvosaurus gurneyi.
Measurements
(mm)
Femur (ML 632)
Maximal length of distal portion 370
Minimal circumference 390
Maximal circumference 600
Anteroposterior diameter of distal diaphysis 110
Lateromedial diameter of distal diaphysis 235
Tibia (ML 430)
Maximum length 820
Minimum circumference 385
Circumference at the level of the fibular crest 470
Fibular crest length 140
Anteroposterior diameter of proximal diaphysis 110
Lateromedial diameter of proximal diaphysis 290
Anteroposterior diameter of distal diaphysis 240
Lateromedial diameter of distal diaphysis 180
doi:10.1371/journal.pone.0088905.t005
Torvosaurus from Portugal
PLOS ONE | www.plosone.org 22 March 2014 | Volume 9 | Issue 3 | e88905
idgian Lourinha˜ Formation (Sobral Member that overlies Porto
Novo-Amoreira Member from which T. gurneyi type comes from)
of Porto das Barcas. The cranial and postcranial elements are
referred to Torvosaurus sp. based on the absence of both medial
antorbital fossa and medial pneumatic complex on the maxilla, tall
interdental plates and blunt anterior margin of the dentary, low
angle of the ascending ramus and the tongue-shaped posterior
extremity of the jugal ramus [9]. As highlighted by these authors,
some notable difference can however be observed in between the
maxilla of the embryonic and adult specimens of Torvosaurus, the
most important being a short anterior ramus, unserrated crowns
and unfused interdental plates, all interpreted as ontogenetic
features. There are four preserved interdental plates for the
maxilla (contra Arau´jo et al. [9]), a first one situated between the
first and second maxillary teeth, a second incomplete one between
teeth 2 and 3 ([9]:fig. 9D), a badly preserved one between teeth 3
and 5 and an isolated one below the maxilla (pers. obs.). As observed
in the interdental plates of the dentary, and similar to the condition
seen in the adult Torvosaurus gurneyi and Megalosaurus bucklandi, the
maxillary interdental plates are tall and all have a vertical
rectangular outline. The lateral wall of the maxilla is not visible in
the embryos ML 1188 and it is unknown whether the interdental
plates were extending at the same level than the ventral margin of
the lateral wall like in T. gurneyi. Nonetheless, the ventral margins of
the plates are straight and do not display the ‘‘V-shaped’’ condition
shared by the American taxon. Likewise, there is no apparent ridge
posterior to the anteromedial process, as seen in T. tanneri.
Nevertheless, these features may all vary ontogenetically in
theropods so that ML 1188 is tentatively assign to the species T.
gurneyi based on paleogeographical and stratigraphical contexts only.
Supporting Information
File S1 Morphological variations in the interdental
plates of Dilophosaurus wetherilli.
(PDF)
Table S1 Morphology of interdental plates in non-
maniraptoriforms theropods.
(PDF)
Text S1 Institutional abbreviations, character list and
datamatrix.
(PDF)
Acknowledgments
The authors would like to thank Aart Walen who discovered and prepared
the Torvosaurus maxilla. We would also like to acknowledge Ronald Tykoski
for the information shared about Dilophosaurus stratigraphic position and
interdental plates morphology, Mickey Mortimer for the precious
information about Dilophosaurus ‘‘breedorum’’ posted on his blog, and Jaime
Headden for the nature of some pneumatic openings in the maxilla of
oviraptorids. The teeth and tooth-bearing bones of many nonavian
theropods were examined in several institutions in Europe and America
and access to the material was possible thanks to Brooks Britt (BYU), Paul
Sereno (Uni. Chicago), Peter Makovicky (FMNH), William Simpson
(FMNH), Matthew Lamanna (CMNH), Amy Henrici (CMNH), Matthew
Carrano (NMNH), Michael Brett-Surman (NMNH), Sandra Chapman
(BMNH), Paul Barrett (BMNH), Paul Jeffery (OUMNH), Stephen Hutt
(MIW), Ronan Allain (MNHN), Rainer Schoch (SMNS), Hans-Jacob Siber
(SMA), Christiano Dal Sasso (MSNM), Alejandro Kramarz (MACN),
Fernando Novas (MACN), Ruben Barbieri (MPCA), Leonardo Salgado
(MUCPv-CH), Juan Ignacio Canale (MUCPv-CH), Rodolfo Coria (MCF-
PVPH), Cecilia Succar (MCF-PVPH), Jorge Calvo (CePaLB), Ricardo
Martı
´nez (PVSJ), Carl Mehling (AMNH), Mark Norell (AMNH), David
Krauze (SBU), Joseph Groenke (SBU), Paul Brinkman (NCSM), Lindsay
Zanno (NCSM), Jorge Sequeira (LNEG), Fareed Krupp (QMA), Khalid
Hassan Al-Jaber (QMA), and Sanker S.B (QMA). A special thanks to
Brooks Britt (BYU) and Matthew Carrano (NMNH) who provided a cast of
the maxilla of Torvosaurus tanneri to the Museu of Lourinha˜ and photos of
the material of Torvosaurus tanneri, respectively. Photographs of theropod
cranial bones and teeth were also kindly shared by Martı
´n Ezcurra (LMU),
Matthew Lamanna (CMNH), , Stephen Brusatte (Uni. Edinburgh), Mick
Ellison (AMNH), Christian Foth (Ludwig-Maximilians-Uni.), Philip Currie
(Uni. of Alberta), Juan Canale (MUCPv-CH), Cristiano Dal Sasso
(MCSN), Oliver Rauhut (Ludwig-Maximilians-Uni.), Roger Benson (Uni.
Oxford), Elisabete Malafaia (MNHNC), Emanuel Tschopp (UNL), Drew
Eddy (Uni. Texas), Ricardo Arau´jo (SMU), Vince Shneider (NCSM),
Karin Peyer (MNHN), Mickey Mortimer, Andrea Cau (MGG), Jonah
Choiniere (Uni. of the Witwatersrand), and the authors would like to
address their sincere thanks to all of these people. We acknowledge the use
of the Willi Hennig Society edition of TNT for the cladistic analysis and
Phylopic for the dinosaur silhouettes. Many thanks to Scott Hartman,
Sima˜o Mateus (ML) and Gregory Paul for accepting to use their artworks.
C.H. dedicates this article to G. A. Martin, J. Hendrickx and E. Poty for
their infinite support.
Author Contributions
Conceived and designed the experiments: CH. Performed the experiments:
CH. Analyzed the data: CH. Contributed reagents/materials/analysis
tools: CH. Wrote the paper: CH OM.
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Torvosaurus from Portugal
PLOS ONE | www.plosone.org 25 March 2014 | Volume 9 | Issue 3 | e88905
... The CPI 477 maxilla is curated at Centro de Interpretación Paleontológica de La Rioja in Igea (La Rioja, Spain). The anatomical description of the left maxilla mainly follows the nomenclature established by Hendrickx and Mateus (2014). Nonetheless, paradental groove, instead of nutrient groove of Hendrickx and Mateus (2014), and interdental bone sensu Currie (1987) (i.e., bone creating a septum between contiguous teeth), which is different from interdental wall and interdental plates (see Hendrickx and Mateus 2014 for an accurate definition of the latter ones), are used. ...
... The anatomical description of the left maxilla mainly follows the nomenclature established by Hendrickx and Mateus (2014). Nonetheless, paradental groove, instead of nutrient groove of Hendrickx and Mateus (2014), and interdental bone sensu Currie (1987) (i.e., bone creating a septum between contiguous teeth), which is different from interdental wall and interdental plates (see Hendrickx and Mateus 2014 for an accurate definition of the latter ones), are used. For the dentition and alveoli, the anatomical nomenclature, descriptions and notations are based on Smith and Dodson (2003) and Hendrickx et al. (2015). ...
... The anatomical description of the left maxilla mainly follows the nomenclature established by Hendrickx and Mateus (2014). Nonetheless, paradental groove, instead of nutrient groove of Hendrickx and Mateus (2014), and interdental bone sensu Currie (1987) (i.e., bone creating a septum between contiguous teeth), which is different from interdental wall and interdental plates (see Hendrickx and Mateus 2014 for an accurate definition of the latter ones), are used. For the dentition and alveoli, the anatomical nomenclature, descriptions and notations are based on Smith and Dodson (2003) and Hendrickx et al. (2015). ...
Article
Spinosaurid dinosaurs show a wide geographical and temporal distribution, being present in Gondwanan and Laurasian landmasses, at least, during the Lower Cretaceous and the Cenomanian. European spinosaurids are more diverse than previously thought with five, and probably six, currently recognised genera. The revision of CPI 477, a fragment of a left maxilla from the Lower Cretaceous of La Rioja (Spain) previously assigned to Baryonyx, demonstrates that this specimen cannot be referred to this genus and likely belongs to an indeterminate baryonychine closer to Baryonyx than to Suchomimus. CPI 477 exhibits a tooth replacement process comparable to that of other theropods and, besides, similar to other large theropods, two replacement teeth could simultaneously be developed in the same alveolus, partly explaining high replacement ratios and the overabundance of spinosaurid teeth in some fossil sites. Furthermore, the Oxalaia maxilla shares the anteriorly located external naris with Irritator and baryonychine spinosaurids, which differ from the more retracted ones in African spinosaurines. Finally, in addition to the previously noticed differences between Baryonychinae and Spinosaurinae, the paradental groove of African spinosaurines and Oxalaia differs from that of baryonychines in being sinusoidal instead of straight.
... The maxillary fenestra of ROM 63777 extends less posterodorsally than initially described because of the medioventral displacement of the ascending process and is more circular than elongate when reconstructed (Fig. 1B). It is housed in a welldefined maxillary fossa with a deep pneumatic excavation (sensu Hendrickx and Mateus, 2014) posterodorsal to the maxillary fenestra proper (Figs. 2C,D,3A,B,4D). ...
... The shape of the medial wall is laterally convex as in Atrociraptor and Saurornitholestes (Fig. 4E, F). Within the sinus system, the promaxillary recess and maxillary antrum are separated by a pronounced preantral strut that is parallel to the posterior boundary of the promaxillary fenestra ( Fig. 3C), similar to other theropods (Hendrickx and Mateus, 2014). The promaxillary recess, however, is quite elongate as this recess occupies all the dorsomedial surface of the anterior ramus, as observed in Saurornitholestes (Figs. 5D, 7B, 7F). ...
... 7C, D, 7G, H, 8A, E). Achillobator and V. osmolskae also possess a sinuous palatal shelf (Perle et al., 1999;Godefroit et al., 2008) like tyrannosaurids (Hendrickx and Mateus, 2014). ...
Article
Eudromaeosauria is a clade of derived dromaeosaurids that typifies the common perception of ‘raptor’ dinosaurs. The evolutionary history of this clade has been controversial due to conflicting views of taxonomic identity, and because, due to taphonomic bias, several species were diagnosed primarily or solely by the maxilla. The maxilla is therefore crucial in understanding the phylogenetic relationships within the clade. Morphometric characterization has been commonly applied to recognize and distinguish major dromaeosaurid clades. However, morphometrics mainly showed morphological convergence rather than phylogenetic relationships. This approach has made it difficult to get resolution of phylogenetic relationships among eudromaeosaurian taxa, often resulting in large polytomies or inconsistent placement of key species. To test previous character statements, computed tomography was used to analyze the maxillae of Acheroraptor, Atrociraptor, and Deinonychus, and compare them with other eudromaeosaurians from Asia and North America. Morphometric characters were examined, and regressions were used to look for allometric trends in maxillary dimensions and the relationship to topological landmarks within Eudromaeosauria and its outgroups. Characters were improved and implemented to better capture eudromaeosaurian morphological variation and better resolve their phylogenetic relationships. Phylogenetic analysis recovered three well-defined clades within Eudromaeosauria and corroborated occurrence data within the fossil record. Acheroraptor and Atrociraptor were recovered as derived members of Saurornitholestinae. Deinonychus is recovered as a basal eudromaeosaurian, sharing features with dromaeosaurines and saurornitholestines. These results challenge previous biogeographic hypotheses suggesting Asian and North American faunal interchange during the Late Cretaceous and support convergence of traits relating to snout dimensions and proportions.
... The anatomical terminologies used in this study are essentially based on the frequency of use in the referred literatures. However, some terminologies coined in previous studies are applied as follows; Hendrickx and Mateus (2014) for the maxilla, Hendrickx et al. (2015) for the dentition, Wilson (1999Wilson ( , 2012 for laminae of vertebrae, Wilson et al. (2011) for fossae of vertebrae, and Nicholls and Russell (1985) for the orientation of the pectoral girdle. ...
... However, the rendered polygon mesh derived from CT images reveals that a faint bony bridge between them is situated medially to the lateral wall of the antorbital fossa (Fig. 4C, E). This bridge probably corresponds to the suprantral strut based on its continuous contact with the postantral strut, resulting in a single large maxillary fenestra expanded further dorsally above the suprantral strut, unlike that of Allosaurus (Hendrickx and Mateus, 2014). Although the maxillary fenestra abuts the anterior margin of the antorbital fossa as in Tsaagan (Norell et al., 2006;Turner et al., 2012), it never extends to the anteroventral corner unlike that of Linheraptor (Xu et al., 2015). ...
... The postantral strut demarcates the posterior margin of the maxillary antrum and the anterior margin of the posteromedial maxillary fenestra (foramen in maxillary pila sensu Choiniere et al., 2014) with both antra connected through a canal lateral to the strut. Posterodorsal to the suprantral strut is the epiantral recess excavating the interfenestral strut (the area between the maxillary and antorbital fenestrae) posteriorly ( Fig. 4E, I, J) as in allosauroids and tyrannosauroids (Hendrickx and Mateus, 2014). The area anterior to the maxillary antrum is severely damaged, while the promaxillary recess is clearly present near the anterodorsal margin of the maxillary body (Fig. 4E). ...
Full-text available
Article
A bizarre coelurosaurian theropod Fukuivenator paradoxus is known only from the holotype specimen preserving majority of the skeleton from the Kitadani Dinosaur Quarry of the Lower Cretaceous Kitadani Formation, Tetori Group, Fukui, Japan. With aids of computed tomography techniques, a re-examination of the holotype specimen reveals additional features of Fukuivenator which was unobservable in the original description, such as the presence of parietals and a quadrate, and the fusion of the posteriormost caudal vertebrae. The thorough description in this study results in the emendation of diagnosis including the retraction of the large promaxillary fenestra subequal in size to maxillary fenestra, and the addition of the large maxillary fenestra expanded well dorsally above the suprantral strut. Expansion of morphological information elaborates the phylogenetic dataset, resulting in locating Fukuivenator as an unambiguous member of Maniraptora at the basalmost position of Therizinosauria. This phylogenetic position of Fukuivenator is supported by several therizinosaurian synapomorphies such as the subotic recess on the braincase, 11 cervical vertebrae some of which having two pneumatic foramina, and distal articular condyles on the anterior surface of the humerus. Among numerous diagnostic features, eight characters shared with some non-maniraptoran coelurosaurs and five shared with different clades within Maniraptora, highlighting the notably mosaic condition of Fukuivenator proposed in the original description. The combination of characters for herbivorous and carnivorous diets suggests the omnivory of Fukuivenator, projecting the dietary shift in the earliest evolutionary stage of Therizinosauria. Also, the large olfactory ratio revealed by the revised brain endocast highlights the unusually high olfactory acuity further developed than the plesiomorphic condition, implying that the acute sense of smell might be a characteristic of therizinosaurian theropods.
... In Gorgosaurus, the palatal (medial) shelf of the maxilla extends anteroposteriorly along the medial surface of the entire length of the bone, terminating anteriorly as the anteromedial process and posteriorly as the palatine contact (Hendrickx and Mateus, 2014). The anteromedial process is nearly straight in the smallest juvenile Gorgosaurus specimens known (TMP 1985.11.3, TMP 1993, as also occurs in Alioramus altai (Brusatte et al., 2012), but is weakly downturned in the slightly larger juveniles TMP 2009.12.14 and TMP 2016.14.1. ...
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Known from dozens of specimens discovered since the early 20th century, Gorgosaurus libratus has arguably contributed more than any other taxon to our understanding of the life history of tyrannosaurids. However, juvenile material for this taxon is rare. Here, we describe two small, articulated Gorgosaurus specimens (skull lengths of ca. 500 mm) that help advance our knowledge of the anatomy and ontogeny of this taxon and of tyrannosaurids in general. The new specimens exhibit hallmark juvenile tyrannosaurid features, including long, low, and narrow skulls, large circular orbits, absent or incipient cranial ornamentation, ziphodont dentition, and an overall gracile skull frame. Comparison with other Gorgosaurus specimens of various ontogenetic stages allows for an examination of the timing of morphological changes that occurred through ontogeny in this taxon relative to other tyrannosaurids. Of particular note, Gorgosaurus and the larger Tyrannosaurus rex are found to have experienced similar ontogenetic transformations at similar percent skull length relative to the large known individuals for each respective taxon but at different absolute body sizes and biological ages, occurring at a larger size and older age in Tyrannosaurus than in Gorgosaurus. These results suggest a dissociation between the timing of cranial development and body size in tyrannosaurids. Finally, the recognition of ontogenetically invariant characters in Gorgosaurus makes it possible to determine the taxonomic identity of previously misidentified specimens.
... replacement teeth in each of them, as seen in the premaxilla of Oxalaia quilombensis [74] and in the maxilla of the megalosauroid, Torvosaururus gurneyi [75]. The distal alveoli (from the 6th alveoli backwards) bear a pattern where the even number alveoli (i.e., 6, 8, 10) have small replacement teeth, meanwhile the odd ones bear a single and big replacement tooth, with the functional teeth being lost most likely due to taphonomic processes [7,9,11]. ...
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Spinosaurids are some of the most enigmatic Mesozoic theropod dinosaurs due to their unique adaptations to aquatic environments and their relative scarcity. Their taxonomy has proven to be especially problematic. Recent discoveries from Western Europe in general, specifically Iberia, provide some of the best specimens for the understanding of their phylogeny, leading to the description of the spinosaurid Vallibonavenatrix cani and the recognition of the Iberian dinosaur Camarillasaurus cirugedae as one of them. Portuguese associated spinosaurid remains (ML1190) from the Papo Seco Formation (early Barremian) were previously assigned to Baryonyx walkeri but new material recovered in 2020 along with new phylogenetic analyses suggests a different phylogenetic placement, making their revision necessary. Here we show that these remains are not attributable to Baryonyx walkeri , but to a new genus and species, Iberospinus natarioi , gen. et sp. nov. The new taxon is characterized by the presence of a single Meckelian foramen in the Meckelian sulcus, a straight profile of the ventral surface of the dentary and a distal thickening of the acromion process of the pubis between other characters. Iberospinus natarioi is recovered as a sister taxon of the clade formed by Baryonyx and Suchomimus , and outside Spinosaurinae when Vallibonaventrix cani is excluded from the analysis. The description of this taxon reinforces Iberia as a hotspot for spinosaur biodiversity, with several endemic taxa for the region. As expected for the clade, the dentary displays a highly vascularized neurovascular network. The morphometric analysis of parts of the skeleton (pedal phalanx and caudal vertebrae, among others) shows an intermediate condition between basal tetanurans and spinosaurines.
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Giant carnivorous dinosaurs such as Tyrannosaurus rex and abelisaurids are characterized by highly reduced forelimbs that stand in contrast to their huge dimensions, massive skulls, and obligate bipedalism.¹,² Another group that follows this pattern, yet is still poorly known, is the Carcharodontosauridae: dominant predators that inhabited most continents during the Early Cretaceous3, 4, 5 and reached their largest sizes in Aptian-Cenomanian times.6, 7, 8, 9, 10 Despite many discoveries over the last three decades, aspects of their anatomy, especially with regard to the skull, forearm, and feet, remain poorly known. Here we report a new carcharodontosaurid, Meraxes gigas, gen. et sp. nov., based on a specimen recovered from the Upper Cretaceous Huincul Formation of northern Patagonia, Argentina. Phylogenetic analysis places Meraxes among derived Carcharodontosauridae, in a clade with other massive South American species. Meraxes preserves novel anatomical information for derived carcharodontosaurids, including an almost complete forelimb that provides evidence for convergent allometric trends in forelimb reduction among three lineages of large-bodied, megapredatory non-avian theropods, including a remarkable degree of parallelism between the latest-diverging tyrannosaurids and carcharodontosaurids. This trend, coupled with a likely lower bound on forelimb reduction, hypothesized to be about 0.4 forelimb/femur length, combined to produce this short-armed pattern in theropods. The almost complete cranium of Meraxes permits new estimates of skull length in Giganotosaurus, which is among the longest for theropods. Meraxes also provides further evidence that carchardontosaurids reached peak diversity shortly before their extinction with high rates of trait evolution in facial ornamentation possibly linked to a social signaling role.
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Postcranial elements (cervical, sacral and caudal vertebrae, as well as ilium, rib and limb bone fragments) belonging to a gigantic tetanuran theropod were recovered from the basal unit (the White Rock Sandstone equivalent) of the Vectis Formation near Compton Chine, on the southwest coast of the Isle of Wight. These remains appear to pertain to the same individual, with enormous dimensions similar to those of the Spinosaurus holotype and exceeding those of the largest European theropods previously reported. A combination of features—including the presence of spinodiapophyseal webbing on an anterior caudal vertebra—suggest that this is a member of Spinosauridae, though a lack of convincing autapomorphies precludes the identification of a new taxon. Phylogenetic analysis supports spinosaurid affinities but we were unable to determine a more precise position within the clade weak support for a position within Spinosaurinae or an early-diverging position within Spinosauridae were found in some data runs. Bioerosion in the form of curved tubes is evident on several pieces, potentially related to harvesting behaviour by coleopteran bioeroders. This is the first spinosaurid reported from the Vectis Formation and the youngest British material referred to the clade. This Vectis Formation spinosaurid is unusual in that the majority of dinosaurs from the Lower Cretaceous units of the Wealden Supergroup are from the fluviolacustrine deposits of the underlying Barremian Wessex Formation. In contrast, the lagoonal facies of the upper Barremian–lower Aptian Vectis Formation only rarely yield dinosaur material. Our conclusions are in keeping with previous studies that emphasise western Europe as a pivotal region within spinosaurid origination and diversification.
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Little is known about the large‐scale evolutionary patterns of skull size relative to body size, and the possible drivers behind these patterns, in Archosauromorpha. For example, the large skulls of erythrosuchids, a group of non‐archosaurian archosauromorphs from the Early and Middle Triassic, and of theropod dinosaurs are regarded as convergent adaptations for hypercarnivory. However, few investigations have explicitly tested whether erythrosuchid and theropod skulls are indeed disproportionately large for their body size, and whether this trend is driven by hypercarnivory. Here, we investigate archosauromorph relative skull size evolution, examining the scaling relationships between skull and body size of Palaeozoic and Mesozoic archosauromorphs using a robust phylogenetic framework and assessing the influence of potential drivers, such as taxonomy, diet, locomotory mode and inhabited biotope. Our results show that archosauromorph relative skull sizes are largely determined by phylogeny and that the other drivers have much weaker levels of influence. We find negative allometric scaling of skull size with respect to body size when all studied archosauromorphs are analysed. Within specific groups, skull size scales with positive allometry in non‐archosaurian archosauromorphs and, interestingly, scales isometrically in theropods. Ancestral reconstructions of skull–femur size ratio reveal a disproportionately large skull at the base of Erythrosuchidae and proportionately sized skulls at the bases of Theropoda, Carnosauria and Tyrannosauroidea. Relative skull sizes of erythrosuchids and theropods are therefore distinct from each other, indicating that disproportionately large skulls are not a prerequisite for hypercarnivory in archosauromorphs, and that erythrosuchids exhibit a bauplan unique among terrestrial Mesozoic carnivores.