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A new carcharodontosaurid (Dinosauria, Theropoda) from the Upper Cretaceous of Argentina

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A new carcharodontosaurid theropod from the Huincul Formation (Aptian-Cenomanian, Upper Cretaceous) of Neuquén Province, Argentina, is described. Approximately the same size as Giganotosaurus carolinii Coria & Salgado, 1995, Mapusaurus roseae n. gen., n. sp. is characterized by many features including a deep, short and narrow skull with relatively large triangular antorbital fossae, relatively small maxillary fenestra, and narrow, unfused rugose nasals. Mapu-saurus roseae n. gen., n. sp. has cervical neural spines and distally tapering epipo-physes, tall dorsal neural spines, central pleurocoels as far back as the first sacral vertebra, accessory caudal neural spines, stout humerus with poorly defined distal condyles, fused metacarpals, ilium with brevis fossa extending deeply into ischial peduncle, and femur with low fourth trochanter. Phylogenetic analysis indicates that Mapusaurus n. gen. shares with Carcharodontosaurus Stromer, 1931 and Giganotosaurus Coria & Salgado, 1995 several derived features that include narrow blade-like teeth with wrinkled enamel, heavily sculptured fa-cial bones, supraorbital shelf formed by a postorbital/palpebral complex, and a dorsomedially directed femoral head. Remains of Mapusaurus n. gen. were recovered from a bonebed where 100% of the identifiable dinosaur bones can be assigned to this new genus. Based on the metatarsals recovered, a minimum of seven individuals was buried at the site. It is conceivable that this bonebed represents a long term or coincidental accumulation of carcasses. The presence of a single carnivorous taxon with individuals of different ontogenic stages pro-vides evidence of variation within a single population, and may also indicate some behavioural traits for Mapusaurus roseae n. gen., n. sp.
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GEODIVERSITAS • 2006 • 28 (1)
© Publications Scientifiques du Muséum national d’Histoire naturelle, Paris. www.geodiversitas.com
A new carcharodontosaurid (Dinosauria,
Theropoda) from the Upper Cretaceous
of Argentina
Rodolfo A. CORIA
CONICET, Museo Carmen Funes, Av. Córdoba 55,
8318 Plaza Huincul, Neuquén (Argentina)
coriarod@copelnet.com.ar
Philip J. CURRIE
University of Alberta, Department of Biological Sciences,
Edmonton, Alberta T6G 2E9 (Canada)
philip.currie@ualberta.ca
Coria R. A. & Currie P. J. 2006. — A new carcharodontosaurid (Dinosauria, Theropoda) from
the Upper Cretaceous of Argentina. Geodiversitas 28 (1) : 71-118.
ABSTRACT
A new carcharodontosaurid theropod from the Huincul Formation (Aptian-
Cenomanian, Upper Cretaceous) of Neuquén Province, Argentina, is described.
Approximately the same size as Giganotosaurus carolinii Coria & Salgado, 1995,
Mapusaurus roseae n. gen., n. sp. is characterized by many features including a
deep, short and narrow skull with relatively large triangular antorbital fossae,
relatively small maxillary fenestra, and narrow, unfused rugose nasals. Mapu-
saurus roseae n. gen., n. sp. has cervical neural spines and distally tapering epipo-
physes, tall dorsal neural spines, central pleurocoels as far back as the first sacral
vertebra, accessory caudal neural spines, stout humerus with poorly defined
distal condyles, fused metacarpals, ilium with brevis fossa extending deeply into
ischial peduncle, and femur with low fourth trochanter. Phylogenetic analysis
indicates that Mapusaurus n. gen. shares with Carcharodontosaurus Stromer,
1931 and Giganotosaurus Coria & Salgado, 1995 several derived features that
include narrow blade-like teeth with wrinkled enamel, heavily sculptured fa-
cial bones, supraorbital shelf formed by a postorbital/palpebral complex, and
a dorsomedially directed femoral head. Remains of Mapusaurus n. gen. were
recovered from a bonebed where 100% of the identifiable dinosaur bones can
be assigned to this new genus. Based on the metatarsals recovered, a minimum
of seven individuals was buried at the site. It is conceivable that this bonebed
represents a long term or coincidental accumulation of carcasses. e presence
of a single carnivorous taxon with individuals of different ontogenic stages pro-
vides evidence of variation within a single population, and may also indicate
some behavioural traits for Mapusaurus roseae n. gen., n. sp.
KEY WORDS
Dinosauria,
eropoda,
Carcharodontosauridae,
Upper Cretaceous,
Argentina,
new genus,
new species.
72 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
INTRODUCTION
Recent discoveries of theropod dinosaurs in the
Cretaceous of Patagonia have unveiled an un-
expected diversity of this group of vertebrates.
ese findings include Carnotaurus sastrei Bona-
parte, 1985; Abelisaurus comahuensis Bonaparte &
Novas, 1985; Xenotarsosaurus bonapartei Martinez,
Gimenez, Rodríguez & Bochatey, 1986; Giganoto-
saurus carolinii Coria & Salgado, 1995; Unenlagia
comahuensis Novas & Puerta, 1997; Megaraptor
namunhuaiki Novas, 1998; Ilokelesia aguada-
grandensis Coria & Salgado, 1998; Quilmesaurus
curriei Coria, 2001; Aucasaurus garridoi Coria,
Chiappe & Dingus, 2002, and several new taxa
still under study. Most of these forms have been
recovered from the Neuquén Basin of northern
Patagonia.
In 1997, members of the Argentinean-Cana-
dian Dinosaur Project were collecting fossils at
the Cañadón del Gato site (Fig. 1) in rocks of
the Huincul Formation of the Río Limay Group
(Ramos 1981; Garrido 2000), which are thought
to be Albian to Cenomanian in age (Legarreta &
Gulisano 1989; Leanza et al. 2004). Excavation
commenced on what was initially thought to be a
single skeleton of a giant theropod (Coria & Currie
1997). Preparation later revealed that skeletal parts
represented more than a single individual, ranging
in size from about five to 11 m.
RÉSUMÉ
Un nouveau carcharodontosauridé (Dinosauria, eropoda) du Crétacé supérieur
d’Argentine.
Un nouveau théropode carcharodontosauride de la Formation Huincul, datée
du Crétacé supérieur, de la Province de Neuquén, Argentine, est décrit. D’une
taille proche de celle de Giganotosaurus carolinii Coria & Salgado, 1995,
Mapusaurus roseae n. gen., n. sp. est défini par des caractères qui incluent : un
crâne haut, court et étroit, avec une fosse antorbitaire assez large, une fenêtre
maxillaire petite et étroite et des os nasaux non fusionnés et d’aspect rugueux.
Au niveau cervical, les vertèbres de Mapusaurus roseae n. gen., n. sp. porte des
épines neurales, et, distalement, des épipophyses effilées, de grandes épines
neurales dorsales, et des pleurocèles centraux jusqu’à la première vertèbre sacrée
et accessoirement des épines neurales dans la région caudale. L’humérus est
robuste avec des condyles distaux peu développés, les métacarpes sont fusion-
nés, l’ilion dont la brevis fossa s’étend loin vers le pédoncule ischiatique. Le
fémur porte un quatrième trochanter en position basse. Les résultats de l’ana-
lyse phylogénétique indiquent que Mapusaurus roseae n. gen., n. sp. partage
avec Carcharodontosaurus Stromer, 1931 et Giganotosaurus Coria & Salgado,
1995 plusieurs caractères dérivés dont : des dents en forme de lame étroite à
émail plissé, des os de la face profondément sculptés, une voûte supraorbitaire
constituée par le complexe postorbitaire-palpébrale et une tête fémorale dirigée
dorsomédialement. Des restes de Mapusaurus n. gen. ont été trouvés dans un
« bonebed » où 100 % des os de dinosaures identifiables sont rapportés à ce
genre. Si l’on prend en considération les métatarses, on peut dénombrer que sept
individus au minimum furent fossilisés sur le site. La formation de ce « bone-
bed » résulterait d’une accumulation d’os sur la durée ou d’une accumulation
plus rapide de carcasses. La présence de ce seul taxon de carnivore représenté
par des individus d’âges différents apporte des données tant sur la variation au
sein d’une seule et même population que sur des traits du comportement de
Mapusaurus roseae n. gen., n. sp.
MOTS CLÉS
Dinosauria,
eropoda,
Carcharodontosauridae,
Crétacé supérieur,
Argentine,
nouveau genre,
nouvelle espèce.
73
A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
FIG. 1. — Location map of the site “Cañadón del Gato” () where the remains of Mapusaurus roseae n. gen., n. sp. were found.
69°17’13’’W
39°03’50’’S
National Route 22
Provincial Route 17
Plaza Huincul
Cutral-Có
Mendoza
Neuquén
Chile
Río Negro
South
America
Argentina
N
After five consecutive field seasons between 1997
and 2001, a minimum of seven to nine individu-
als have been recognized, all assigned to a single
theropod species. e monospecific nature of the
assemblage makes the Cañadón del Gato site inter-
esting, especially considering the rarity of fossilized
bones in the Huincul Formation (Eberth et al. 2000).
e monospecific nature and some taphonomic
characteristics of the burial have implications on
our understanding of the social behavior of large
theropods (Currie 2000).
e specimens collected from the Cañadón del
Gato site share derived characters with members
of the Carcharodontosauridae. ese include heavy
sculpturing of the external surface of the maxilla;
heavily ornamented, thick, unfused nasals; a strongly
upturned femoral head; and a distally positioned
lesser trochanter. Carcharodontosaurids, one of the
most poorly understood large Cretaceous theropod
families, have been recovered from Africa (Depéret
& Savornin 1927; Stromer 1931; Rauhut 1995;
Russell 1996; Sereno et al. 1994) and South America
(Coria & Salgado 1995; Vickers-Rich et al. 1999).
e report of a possible carcharodontosaurid from
Japan (Chure et al. 1999) is based on a single
tooth, and its identification can only be considered
tentative. Although Acrocanthosaurus Stovall &
Langston, 1950, from the United States, has been
referred to the Carcharodontosauridae (Sereno et
al. 1996; Harris 1998), the assignment has been
questioned by others (Currie & Carpenter 2000;
Coria & Currie 2002).
Giganotosaurus (Coria & Salgado 1995) was
the first South American carcharodontosaurid
74 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
identified (Sereno et al. 1996). Since then, carcha-
rodontosaurid remains have been reported from
widespread South American localities (Novas et
al. 1999; Vickers-Rich et al. 1999; Calvo & Coria
2000; Rich et al. 2000). In this contribution, we
describe a new carcharodontosaurid, Mapusaurus
roseae n. gen., n. sp., which can be distinguished
from Giganotosaurus carolinii on the basis of ana-
tomical differences and stratigraphic provenance.
Nevertheless, Mapusaurus n. gen. is an animal
of comparable size to Giganotosaurus (Coria &
Salgado 1995), arguably the largest known thero-
pod, suggesting a previously unrecognized diversity
of large-sized theropods in the Late Cretaceous of
South America. Furthermore, Mapusaurus n. gen.
is associated in the Huincul Formation with giant
sauropods, including Argentinosaurus huinculensis
Bonaparte & Coria, 1993.
In recent years, the analysis of theropod systematics
(Harris 1998; Sereno 1999; Holtz 2000; Currie &
Carpenter 2000) has become complicated because
of the wealth of information from newly described
basal forms (Currie & Zhao 1993; Zhao & Currie
1993; Sereno et al. 1994; Coria & Salgado 1995,
2000; Hutt et al. 1996; Coria 2001; Coria et al.
2002; Arcucci & Coria 2003). Although there is
broad agreement on the relationships of many of
the major theropod lineages, the positions of specific
branches are in a state of flux, including the compo-
sition and relationships of Carcharodontosauridae.
Consider, for example, that carcharodontosaurids
have been allied with tyrannosaurids (Lapparent
1960), megalosaurids (Romer 1966), allosauroids
(Rauhut 1995; Sereno et al. 1996; Harris 1998;
Currie & Carpenter 2000), and abelisaurids (Novas
1997). Although the family has been known for more
than 70 years (Stromer 1931), detailed descriptions
of carcharodontosaurid anatomy are only starting
to be published (Larsson 2001; Coria & Currie
2002). In this contribution, we present a descrip-
tion of the characters that support the new taxon
Mapusaurus roseae n. gen., n. sp., and conduct a
preliminary phylogenetic analysis.
ABBREVIATIONS
BHI Black Hills Institute of Geological Re-
search, Hill City, South Dakota;
BMNH e Natural History Museum, London;
FPDM Fukui Prefectural Dinosaur Museum,
Katsuyama, Japan;
MACN Museo Argentino de Ciencias Naturales,
Buenos Aires;
MCF-PVPH Museo Carmen Funes, Paleontología de
Vertebrados, Plaza Huincul, Neuquén;
MPCA Museo Provincial “Carlos Ameghino”,
Cipolletti, Río Negro;
MUCPv-CH Museo de la Universidad Nacional
del Comahue, El Chocón collection,
Neuquén;
NCSM North Carolina State Museum of Natural
Sciences, Raleigh;
SGM Ministère de l’Énergie et des Mines,
Rabat;
USNM United States National Museum of
Natural History, Smithsonian Institu-
tion, Washington, D.C.;
UUVP University of Utah, Vertebrate Paleon-
tology, Salt Lake City.
SYSTEMATICS
DINOSAURIA Owen, 1842
THEROPODA Marsh, 1881
Family CARCHARODONTOSAURIDAE
Stromer, 1931
GIGANOTOSAURINAE n. subfam.
TYPE GENUS. — Giganotosaurus Coria & Salgado, 1995.
DIAGNOSIS. — Carcharodontosaurids linked by the de-
rived femur with a weak fourth trochanter, and a shallow,
broad extensor groove on the distal end.
Mapusaurus n. gen.
TYPE SPECIES. — Mapusaurus roseae n. sp.
ETYMOLOGY. — Mapu” is a Mapuche (local indigenous
people) term for Earth. erefore “Mapusaurus” should
be translated as “Earth reptile”.
HORIZON AND LOCALITY. — Huincul Formation, Río
Limay Group (Cenomanian), of the Neuquén Group.
Cañadón del Gato in the Cortaderas area 20 km south-
west of Plaza Huincul, Neuquén Province, Argentina
(Fig. 1).
75
A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
DIAGNOSIS. — Mapusaurus n. gen. is a carcharodonto-
saurid theropod whose skull differs from Giganotosaurus
in having thick, rugose unfused nasals that are narrower
anterior to nasal/maxilla/lacrimal junction; larger exten-
sion of antorbital fossa onto maxilla; smaller maxillary
fenestra; wider bar (interfenestral strut) between antor-
bital and maxillary fenestrae; lower, flatter lacrimal horn;
transversely wider prefrontal in relation to lacrimal width;
ventrolaterally curving lateral margin of palpebral; shal-
lower interdental plates; higher position of Meckelian
canal; more posteriorly sloping anteroventral margin of
dentary. Mapusaurus roseae n. gen., n. sp. is unique in
that upper quadratojugal process of jugal splits into two
prongs; small anterior mylohyoid foramen positioned
above dentary contact with splenial; second and third
metacarpals fused; humerus with broad distal end and
little separation between condyles; brevis fossa of ilium
extends deeply into excavation dorsal to ischial pedun-
cle. It also differs from Giganotosaurus in having conical,
slightly curving cervical epipophyses that taper distally;
axial posterior zygapophyses joined on midline; smaller
and less elaborate prespinal lamina on midline of cervi-
cals; remarkably sharp dorsal margin of cervical neural
spines; taller, wider neural spines; curved ischiatic shaft;
more slender fibula.
Mapusaurus roseae n. sp.
HOLOTYPE. — MCF-PVPH-108.1, right nasal.
PARATYPES. — MCF-PVPH-108.5, left lacrimal/pre-
frontal; MCF-PVPH-108.45, right humerus; MCF-
PVPH-108.83, axis; MCF-PVPH-108.90, cervical
neural arch; MCF-PVPH-108.115, right maxilla; MCF-
PVPH-108.125, left dentary; MCF-PVPH-108.128,
left ilium; MCF-PVPH-108.165, left ischium; MCF-
PVPH-108.167, jugal; MCF-PVPH-108.177, right post-
orbital-palpebral; MCF-PVPH-108.179, right splenial;
MCF-PVPH-108.202, right fibula.
ETYMOLOGY. — e term “roseaerefers to the rose-
colored rocks that surround the site where Mapusaurus
n. gen. was found, and to Rose Letwin (Seattle) who
sponsored the expeditions in 1999, 2000 and 2001.
DIAGNOSIS. — e same as genus by monotypy.
DESCRIPTION
Mapusaurus roseae n. gen., n. sp. is known from most
skeletal parts, although the bones represent at least
seven individuals (discussed in subsequent text).
Overall, the skull of Mapusaurus n. gen. appears to
be deeper and narrower than that of Giganotosaurus,
because the maxilla is not elongate, and the nasal is
relatively narrower (Figs 2; 3). e antorbital fossa
of Mapusaurus roseae n. gen., n. sp. is as large as in
Giganotosaurus (MUCPv-CH-1) and Carcharodon-
tosaurus Stromer, 1931 (SGM-Din 1). It is almost
triangular, with a height close to its anteroposterior
length. e fossa extends anteriorly onto the lateral
surface of the maxilla for a short distance. ere is
a maxillary fenestra that is barely visible in lateral
view. Posterodorsally the fossa is continuous with a
pair of pneumatopores in the lacrimal, and postero-
ventrally it invades the jugal. e orbit is subdivided
into upper and lower regions by processes of the
lacrimal and possibly by the postorbital as well,
although this character, present in Giganotosaurus
(MUCPv-CH-1), remains unclear for Mapusaurus
n. gen. As in all other theropods, the eye was housed
in the upper part of the orbital opening. A nearly
vertical postorbital bar separates the orbit and lateral
temporal fenestra. Based on the sizes and shapes of
the jugal and quadrate, the lower temporal fenestra
seems to have been as large an opening as in the
other carcharodontosaurids.
e maxilla (Fig. 2) is known from three speci-
mens from the left side (MCF-PVPH-108.11,
-108.142, -108.169) and two from the right
(MCF-PVPH-108.115, -108.138). e largest
well preserved maxilla (MCF-PVPH-108.169) is
620 mm long, but lacks most of the jugal process
(Fig. 2A, B). e maxillary tooth row is 560 mm
long, which is 90 mm shorter than the preserved
portion of the tooth row in the holotype of Gi-
ganotosaurus. MCF-PVPH-108.115 (Fig. 2C, D)
is a right maxilla of a slightly smaller individual
(tooth row length is 520 mm). It is virtually com-
plete, and displays a number of differences from
Giganotosaurus. For example, it is relatively tall
compared with its length, whereas the maxilla
of Giganotosaurus is more elongate. Mapusaurus
n. gen. and the other carcharodontosaurids lack
the elongate anterior (rostral) rami of the maxil-
lae that are present in Afrovenator Sereno, Wilson,
Larsson, Dutheil & Sues, 1994, “Megalosaurus
hesperis Waldman, 1974 (BMNH R332), and
Monolophosaurus Zhao & Currie, 1993.
As in Allosaurus Marsh, 1877, Sinraptor Currie &
Zhao, 1993, Yangchuanosaurus Dong, Chang, Li &
Zhou, 1978 and most other large theropods (Currie
76 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
& Zhao 1993), the lateral surface of MCF-PVPH-
108.115 is rugose only along its anterior edge and
immediately above the tooth row (Fig. 2C), and
is not as rugose laterally as those of abelisaurids
(Bonaparte & Novas 1985; Bonaparte et al. 1990;
Lamanna et al. 2002). However, MCF-PVPH-
108.169 and MCF-PVPH-108.11 (Fig. 2A, B,
E-G) represent larger animals than MCF-PVPH-
108.115, and the external surfaces of their maxil-
lae are more rugose. In Giganotosaurus, the lateral
surface of the bone posterior to the narial opening
is relatively smooth, whereas the lateral surface of
the maxilla of Mapusaurus n. gen. is sculptured for
most of its length.
e main body of the maxilla tapers posteriorly
beneath the antorbital fossa as in Carcharodonto-
saurus (Sereno et al. 1996), which contrasts strongly
with Giganotosaurus where the dorsal and ventral
margins of the region below the antorbital fenestra
are almost parallel for most of their length (MUCPv-
CH-1). e antorbital fossa extends 75 mm beyond
the anterior margin of the antorbital fenestra in
MCF-PVPH-108.169 (Fig. 2A), and 70 mm in
MCF-PVPH-108.115 (Fig. 2C). e smooth sur-
face for the fossa tapers posteroventrally behind
the anterior margin of the antorbital fenestra, but
a ridge separates it from the lateral surface of the
maxilla. As in other carcharodontosaurids, the area
between the margins of the antorbital fossa and ant-
orbital fenestra is not as extensive as in Ceratosaurus
Gilmore, 1920, Indosuchus Huene & Matley, 1933
(Chatterjee 1978), Torvosaurus Galton & Jensen,
1979 (Britt 1991) and most coelurosaurs.
e posterior end of the lacrimal (posterodor-
sal) process of the maxilla of Mapusaurus n. gen.
(Fig. 2C) bifurcates, as in most theropods, for the
insertion of the anteroventral process of the lacrimal.
e posterior half of the lacrimal process, along
with the nasal and lacrimal, form the dorsomedial
limit of the antorbital fossa. In tyrannosaurids, in
contrast, the upper limit of the antorbital fossa
is formed by the lacrimal process of the maxilla
(Currie pers. obs.).
Unlike Acrocanthosaurus, Allosaurus and most
advanced carnosaurs (Currie & Carpenter 2000),
there is only a single accessory opening in the max-
illa anterior to the antorbital fenestra. is opening
is the maxillary fenestra. e fenestra is relatively
small, and the opening itself is not visible in lateral
aspect. However, a round depression 34 mm high
leads into this fenestra in MCF-PVPH-108.115
(Fig. 2C) and can be seen posteromedial to the
anterior rim of the antorbital fossa. In Giganoto-
saurus, this opening is larger (78 mm), triangular,
exposed laterally, and positioned relatively lower.
e single fenestra anterior to the antorbital fe-
nestra of Mapusaurus n. gen. compares well with
Abelisaurus, Afrovenator, Carnotaurus, Ceratosaurus,
Carcharodontosaurus, Giganotosaurus, Indosuchus,
Majungatholus Sues & Taquet, 1979 (Sampson et
al. 1998), Monolophosaurus and Torvosaurus. e
fenestra passes anteromedially into a medially fac-
ing, large depression on the internal surface of the
maxilla that may be the promaxillary recess, but is
more likely the maxillary antrum. It is separated
from a more posterior depression by a dorsally ta-
pering bar of bone (probably the postantral strut)
that rises vertically from the palatal shelf (Fig. 2B,
D). is bar of bone is pierced ventrally by an
opening (the posterior fenestra of the maxillary
antrum) that connects the two medial depressions
(MCF-PVPH-108.115, -108.169). If this bar of
bone is in fact the postantral strut and the more
anterior depression is the maxillary antrum, then
the single opening in the anterior rim of the antor-
bital fossa is best interpreted as a maxillary fenestra.
e floor of the maxillary antrum is pierced by a
large pneumatopore (diameter of 4 cm) that leads
into a huge sinus lateral to the anteromedial proc-
ess (MCF-PVPH-108.11, Fig. 2E), which may be
the promaxillary recess.
e pronounced anteromedial process (Fig. 2B,
D, F, G) extends from the anterior end of the wide
palatal shelf to protrude anteriorly beyond the level
of the lateral surface (Fig. 2C) of the maxilla as in
most theropods. MCF-PVPH-108.115 also shows
the premaxillary suture, which tapers posterodorsally
and seems to reach the nasal suture. is suggests
that the maxilla was excluded from the margin of the
external naris by the contact between the premaxilla
and nasal as in the majority of theropods.
On the medial surface, the interdental plates are
fused to each other and to the margin of the maxilla
as in abelisaurids (Lamanna et al. 2002), Allosaurus
77
A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
FIG. 2. — Mapusaurus roseae n. gen., n. sp.: A, B, left maxilla (MCF-PVPH-108.169); A, lateral view; B, medial view; C, D, right maxilla
(MCF-PVPH-108.115); C, lateral view; D, medial view; E-G, left maxillary fragment (MCF-PVPH-108.11); E, posterior view; F, medial
view; G, anterior view. Abbreviations: 1, 3, 12, first, third and 12th alveoli; af, antorbital fossa; amp, anteromedial process; ap, as-
cending process; ma, maxillary antrum; mf, maxillary fenestra; pa, postantral strut; pmr, promaxillary recess; ps, palatal shelf. Scale
bars: 10 cm.
A B
C D
E F
mf
G
af ps mf
pa ma
amp
ap
mf
af
amp
ma
pa
ps
12
3
ma pmr
ma
amp
1?
(Madsen 1976a), Giganotosaurus (MUCPv-CH-
1), Torvosaurus (Britt 1991), and dromaeosaurids
(Currie 1995), but in contrast with Marshosaurus
Madsen, 1976 (Madsen 1976b), Megalosaurus
hesperis (BMNH R332), Monolophosaurus (Zhao
& Currie 1993), Piatnitzkysaurus Bonaparte, 1986,
Sinraptor (Currie & Zhao 1993), and tyrannosau-
rids (Witmer 1997). e interdental plates do not
extend as far ventrally as the lateral margin of the
maxilla (Fig. 2B, D).
ere are 12 maxillary alveoli in Mapusaurus
n. gen. (MCF-PVPH-108.125, -108.169), com-
pared with 14 in Carcharodontosaurus (Sereno et
al. 1996). e exact number of maxillary teeth in
78 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 3. — Mapusaurus roseae n. gen., n. sp.: A-C, right nasal
(MCF-PVPH-108.1); A, lateral view; B, dorsal view; C, ventral
view; D, right nasal fragment (MCF-PVPH-108.12) in lateral view;
E, F, left nasal fragment (MCF-PVPH-108.17); E, dorsal view; F,
ventral view. Abbreviations: en, external naris; fc, frontal contact;
lc, lacrimal contact; mc, maxillary contact; pn, pneumatopores.
Scale bar: 10 cm.
A
B
C
D
fc
lc pn mc
en
lc mc
E
F
Giganotosaurus is unknown, but it was at least 12
(MUCPv-CH-1).
e long, massive nasals (MCF-PVPH-108.1,
-108.12, -108.17; Fig. 3) are not co-ossified and
are relatively smooth and shallowly concave be-
hind the narial region as in carcharodontosaurids
and allosauroids. e nasals show the remarkable
condition of having well developed dorsolateral
rugosities above the antorbital fossa (Fig. 3A-C).
As in Giganotosaurus (MUCPv-CH-1) and Car-
charodontosaurus (SGM-Din 1), the rugosities
expand transversely anterior to the nasal-lacrimal-
maxilla junction until they cover the entire dorsal
surface of the anterior part of the bone (Fig. 3A,
B). Rugosities on the dorsolateral margin of the
nasal are common in many other theropods, in-
cluding Allosaurus, Acrocanthosaurus and Sinraptor
(Madsen 1976a; Currie & Zhao 1993; Currie &
Carpenter 2000), but they are never as prominent
as in Mapusaurus n. gen., Carcharodontosaurus and
Giganotosaurus. Abelisaurid nasals (Bonaparte &
Novas 1985; Bonaparte et al. 1990; Sampson et
al. 1998), in contrast, have dorsal surfaces that are
convex in cross-section, and are almost entirely
rugose. is is also characteristic for tyrannosau-
rids (Russell 1970).
e posterodorsal margin of the external naris is
partially preserved in MCF-PVPH-108.12 (Fig. 3D),
behind which is a shallow depression that was called
a narial fossa in Carcharodontosaurus (Sereno et al.
1996). ere was a long subnarial process that prob-
ably extended forward to contact the premaxilla as
in most theropods.
In MCF-PVPH-108.17, there is a finger-like
process extending posterolaterally from the main
body of this left nasal fragment (Fig. 3E, F). It is
grooved on the ventral surface, presumably for
contact with the anterior tip of the lacrimal as in
Sinraptor (Currie & Zhao 1993). ere is also a
long, curving trough, best seen in MCF-PVPH-
108.1, for articulation with the dorsal edge of
the maxilla. Lateral to the area where the trough
is closest to the midline, the nasal forms a lateral
shelf that roofs the antorbital fossa. As in Allosaurus
(Gilmore 1920), Giganotosaurus (MUCPv-CH-1)
and Sinraptor (Currie & Zhao 1993), this shelf
is pierced by two pneumatopores (25 mm in dia-
meter) that probably pneumatized the nasal as in
Giganotosaurus and Sinraptor. Nasal pneumatopores
are highly variable in number and size (Currie &
Zhao 1993), and therefore should be treated with
caution in phylogenetic analysis.
e lacrimal (MCF-PVPH-108.5, -108.100,
-108.101, -108.183) of Mapusaurus n. gen. (Fig. 4)
has a flattened preorbital process that expands
anteroposteriorly towards the bottom as in most
other theropods. In lateral view, the posterior edge
of the preorbital process has a rounded projec-
tion that marks the lower limit of the eye socket
(Fig. 4A, E). is small convexity is also present
in Abelisaurus (Bonaparte & Novas 1985), Majun-
gatholus (Sampson et al. 1998), Monolophosaurus,
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A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
FIG. 4. — Mapusaurus roseae n. gen., n. sp.: A-D, left lacrimal-prefrontal complex (MCF-PVPH-108.183); A, left lacrimal in lateral view; B,
posterior view; C, anterior view; D, medial view; E-H, left lacrimal (MCF-PVPH-108.5); E, lateral view; F, posterior view; G, anterior view;
H, medial view. Abbreviations: af, antorbital fossa; ls, lacrimal recess; pc, preorbital convexity; pf, prefrontal. Scale bar: 10 cm.
A B C D
EFGH
pc
af
ls pf
af
pc
ls pf
Sinraptor and Yangchuanosaurus (Currie & Zhao
1993). e lateral surface of the upper part of this
process is shallowly concave, whereas it is convex
in Giganotosaurus. ere are well defined margins
on the lateral surface for the posterodorsal and
posteroventral limits of the antorbital fossa. One or
80 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
more pneumatopores expand into a large sinus (the
lacrimal pneumatic recess of Witmer 1997) from
the posterodorsal corner of the antorbital fossa,
as in Giganotosaurus and most other theropods.
e lacrimal duct passes through the uppermost
region of the preorbital bar in MCF-PVPH-108.5
and -108.183 (Fig. 4). Unlike Allosaurus, Cerato-
saurus, Sinraptor and albertosaurine tyrannosaurids
(Currie 2003b), there is no conical lacrimal horn.
e posterodorsal surface of MCF-PVPH-108.5
is in the same plane as the dorsal surface of the
prefrontal, and is only slightly elevated and ridge-
like on the dorsolateral margin in comparison
with Giganotosaurus and Carcharodontosaurus. In
both MCF-PVPH-108.5 and -108.183, despite
their size difference, the angle between the dor-
sal and medial surfaces is 106° in anterior view.
erefore, this feature might not be controlled by
ontogeny. In the largest lacrimal of Mapusaurus
n. gen. (MCF-PVPH-108.183), which is 350 mm
high, the dorsal surface is rugose, whereas that of
Giganotosaurus (MUCPv-CH-1) has deep grooves
in the long, ridge-like horn. e posterolateral
edge in posterior aspect forms a sutural surface,
presumably for contact with the palpebral.
e prefrontal is fused to the lacrimal (MCF-
PVPH-108.5, -108.183), as in Giganotosaurus
and many other theropods (Fig. 4D, H). It is a
relatively large, triangular bone in dorsal view
that is slightly wider than the adjacent part of the
lacrimal in MCF-PVPH-108.5. e dorsal surface
is smooth and almost flat. e prefrontal forms a
posteromedial sub-horizontal ridge anterodorsal
to the orbit. e posterolaterally facing surface
of this ridge is smooth in MCF-PVPH-108.5,
whereas in MCF-PVPH-108.183 the surface is
rugose, likely for the contact with the palpebral-
postorbital complex as in Giganotosaurus and
probably Carcharodontosaurus (Coria & Currie
2002). is difference is correlated with a differ-
ence in size of the two specimens and is probably
ontogenetic. A tall, rod-like, ventrally tapering
process extends almost half way down the medial
side of the orbital margin of the lacrimal (MCF-
PVPH-108.5, -108.183). On the medial surface of
the prefrontal, there is a triangular, interdigitating
suture for the frontal (Fig. 4).
In Mapusaurus n. gen. (MCF-PVPH-108.4,
-108.153, -108.177; Fig. 5), there is a supraor-
bital shelf formed either by the postorbital, or by
an additional bone that is fused to the front of the
postorbital as in Giganotosaurus (Coria & Currie
2002). On the right side of the skull of the Gigano-
tosaurus holotype (MUCPv-CH-1), the supraor-
bital shelf is a separate bone that is best identified
as the palpebral. In Mapusaurus n. gen., the shelf
is similar in shape to that of Giganotosaurus, sug-
gesting that it is formed by a co-ossified postorbital
and palpebral. Palpebrals also seem to be present
in Abelisaurus (MPCA 11098) and Carcharodon-
tosaurus (SGM-Din 1).
Like Giganotosaurus, the palpebral of Mapusaurus
n. gen. roofed over the orbit and contacted both
the prefrontal and lacrimal anteriorly. e dorsal
surface is not as rugose as that of the Giganotosau-
rus palpebral (MUCPv-CH-1). e angle between
the postorbital bar and the palpebral is acute in
lateral view in Mapusaurus n. gen. and obtuse in
Giganotosaurus. Furthermore, the lateral margin
of the palpebral extends relatively farther from the
postorbital in the former genus, and curves more
ventrally so that the dorsal surface can be seen in
lateral aspect. Laterally, it bridged the orbital notch
(an emargination of the orbital rim between the
frontal, prefrontal and postorbital in most large
theropods), separating the medial part of the notch
from the orbital rim. In MCF-PVPH-108.4 and
-108.177, the palpebral is fused posteriorly to the
postorbital. e co-ossification of the bones is
complete, and only a pair of foramina (Fig. 5D)
marks the position of contact between the palpe-
bral and postorbital. In MCF-PVPH-108.177,
the medial edge of the palpebral is 11 mm thick
(high) over the orbit, but thickens anterolaterally to
44 mm at the contact with the lacrimal. In lateral
view, the palpebral is 26 mm over the orbit, but
thickens posteriorly to 37 mm above the back of
the orbit, where it forms a somewhat rugose boss.
In Acrocanthosaurus, the prefrontal and postorbital
form the supraorbital shelf, and the lacrimal may
participate in the dorsal part of the orbital margin
(Currie & Carpenter 2000). In Tyrannosaurus rex,
the major contact is between the postorbital and
lacrimal. However, one specimen, BHI 3033, has
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A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
FIG. 5.— Mapusaurus roseae n. gen., n. sp., right postorbital-palpebral complex (MCF-PVPH-108.177): A, lateral view; B, medial view;
C, dorsal view; D, ventral view; E, posterior view. Abbreviations: lc, lacrimal contact; pal, palpebral; po, postorbital; po-p, suture
postorbital-palpebral; sc, supraorbital crest. Scale bar: 10 cm.
A B
C D
E
sc po
pal
lc
pal
po
sc
po
pal
po
sc
po-p
sc
po
pal
an additional, small bone that sits on the outside
of the postorbital boss and appears to have been
a palpebral.
Medially, the postorbital of Mapusaurus n. gen.
(MCF-PVPH-108.4, -108.177) has a relatively small
contact surface with the frontal-parietal (Fig. 5B).
Posteroventral to this there is a long, concave,
crescentic sutural surface for the laterosphenoid.
A powerful ridge on the dorsal surface extends
posterolaterally to form the anterior limit of the
supratemporal fossa. As in Giganotosaurus (Coria
& Currie 2002), this ridge slightly overhangs the
fossa. Behind the ridge, the dorsal surface of the
postorbital is deeply invaded anteromedial to the
intertemporal bar for the origin of temporal muscu-
lature. On the medial surface of the intertemporal
bar there is a deep groove near the dorsal margin
for the upper fork of the anterior ramus of the squa-
mosal (Fig. 5B). Ventrally, the jugal ramus of the
postorbital is anteroposteriorly broad and forms a
convex projection into the anterodorsal corner of
the lateral temporal fenestra.
Two left jugals (MCF-PVPH-108.167, -108.168)
were recovered from the Cañadon del Gato bonebed
(Fig. 6). e anterolateral surface of the jugal is de-
pressed where it contributes to the antorbital fossa
(Fig. 6A). A single, 36 mm high slit-like pneumatic
opening (jugal pneumatic recess) invades the jugal
from the posteroventral edge of this depression in
MCF-PVPH-108.168. Allosaurus (USNM 4734,
UUVP 1403, UUVP 3894, UUVP 3981), Mono-
lophosaurus (Zhao & Currie 1993), sinraptorids
(Currie & Zhao 1993) and tyrannosaurids also
have pneumatized jugals. However, only the last
two taxa have openings that are as large as Mapu-
saurus n. gen. e ventral margin of the front of
the jugal (MCF-PVPH-108.168; Fig. 6A, D) is
emarginated for its contact with the maxilla. is
82 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 6. — Mapusaurus roseae n. gen., n. sp.: A, left jugal (MCF-
PVPH-108.167) in lateral view; B, C, left jugal (MCF-PVPH-108.168);
B, lateral view; C, medial view; D, reconstruction of jugal in lateral
view. Abbreviations: l, overlapping external surface of maxilla; lp,
lower prong; lup, large upper prong; ms, medioventral shelf; mx,
maxillary suture; pn, pneumatopore (jugal pneumatic recess); po,
postorbital suture; qj, quadratojugal suture; r, ridge; s, socket for
back of maxilla; sup, small upper prong. Scale bars: 10 cm.
A
B
C
D
l
s
qj
ms
po
lup
qj
lp
sup
r
mx
l
pn
contact, which overlaps the maxilla dorsally and
somewhat medially, ends posteriorly in a socket
below the orbit (Fig. 6B). Close to the anterior end
of the jugal, there is a lappet on the ventrolateral
margin that overlaps the external surface of the
maxilla (Fig. 6B, D). ere is a conspicuous ridge
on the lateral surface of the jugal posteroventral to
the orbit (Fig. 6A, B, D). is is in the position
of a low, cone-like process or rugosity in many
large theropods, and presumably marked the at-
tachment of cheek musculature. e postorbital
process of the jugal is triangular in lateral view, and
distinctly broad-based (Fig. 6). As in Sinraptor and
Allosaurus, the sloping, laterally overlapping contact
for the postorbital bone does not reach the lower
margin of the orbit, whereas in Edmarka these
are at the same level (Bakker et al. 1992). In most
theropods, the quadratojugal process of the jugal
splits posteriorly into two prongs. In Mapusaurus
n. gen. (MCF-PVPH-108.167), the upper of the
two prongs autapomorphically subdivides into two,
so there is in fact a total of three prongs on the
quadratojugal process of the jugal (Fig. 6B, D). e
short lower process of the upper prong presumably
fits in a groove on the anterolateral surface of the
quadratojugal. e dorsal edge of the lower prong
was laterally overlapped by the anteroventral margin
of the quadratojugal. is suture extends anteriorly
beyond the bifurcation of the prongs. Curiously, the
jugal of Sinraptor dongi also has three quadratojugal
prongs (Currie & Zhao 1993), although it is the
lower of the normal two prongs that subdivides
into two, and it fits on a groove on the internal
surface of the quadratojugal. e upper and lower
quadratojugal processes of MCF-PVPH-108.168
are incomplete distally so it is not possible to de-
termine which one was longer. e lower prong is
lateromedially thicker, however, suggesting that it
may have been longer than the dorsal process. e
medial surface of the jugal (Fig. 6C) is concave at
the base of the postorbital process, and the con-
cavity extends posteriorly to form a deep trough
between the prongs of the quadratojugal process.
e ventral prong forms a broad medioventral shelf
(Fig. 6C) as in Sinraptor.
e quadrate (MCF-PVPH-108.6, -108.102,
-108.170) of Mapusaurus n. gen. (Fig. 7) is tall
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A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
FIG. 7. — Mapusaurus roseae n. gen., n. sp., left quadrate (MCF-
PVPH-108.102): A, posterior view; B, medial view; C, anterior view;
D, lateral view. Abbreviations: pn, pneumatopore; qf, quadratic
foramen. Scale bar: 10 cm.
A B
C D
qf
qf
pn
with a broadly expanded mandibular articulation
as in Giganotosaurus and abelisaurids. e preserved
quadrates are between 310 and 350 mm tall, all
of which are significantly less than the 410 mm
tall quadrate of Giganotosaurus. In contrast with
abelisaurids and Ceratosaurus (Bakker 2000), a
quadratic foramen is present between the quadrate
and quadratojugal, although it was relatively small
compared with those of dromaeosaurids, tyranno-
saurids and many other theropods (Fig. 7A, C, D).
e quadratic foramen of allosauroids is different
in that it is virtually surrounded by the quadrate
in Acrocanthosaurus (Currie & Carpenter 2000),
Allosaurus (Madsen 1976a) and Sinraptor (Currie
& Zhao 1993). Unlike Carnotaurus and tyran-
nosaurids, there is no fusion between quadrate
and quadratojugal. Instead, it shows a compara-
ble condition to Giganotosaurus, Sinraptor and
other primitive theropods. e ventral suture for
the quadratojugal is almost round (MCF-PVPH-
108.6) and has a rugose, slightly concave surface.
e pterygoid flange of MCF-PVPH-108.170
(Fig. 7B) is as long (179 mm) anteroposteriorly as
it is tall. e quadrate cotyle is considerably smaller
than that of Giganotosaurus. Although the largest
quadrate of Mapusaurus n. gen. is only 77% that
of the holotype of Giganotosaurus, the diameter
of the quadrate cotyle is only 64%. e quadrate
of Mapusaurus n. gen. (MCF-PVPH-108.102) is
pneumatic like those of tyrannosaurids. e pneu-
matopore is on the medial surface of the quadrate
between the pterygoid flange and the main vertical
shaft of bone. It is 20% of the total height of the
bone in MCF-PVPH-108.170 (Fig. 7C). A ridge
extends anteriorly (and somewhat dorsally) above
the depression housing the pneumatopores and
extends onto the medial surface of the pterygoid
flange. is ridge defines the ventral margin of a
second pneumatic depression that is also well de-
fined in tyrannosaurids (Currie 2003b)
Four partial dentaries (MCF-PVPH-108.2, -108.3,
-108.39, -108.125) have been collected from the
Cañadón del Gato bonebed (Fig. 8). e mini-
mum height of the dentigerous part of the dentary
is 112 mm in MCF-PVPH-108.2 (Fig. 8A, B),
whereas MCF-PVPH-108.3 (Fig. 8E, F) is half the
height (56 mm) and represents a juvenile with a
body length of about 5 to 5.5 m (Table 1). MCF-
PVPH-108.125 (Fig. 8C, D) is an almost complete
dentary, 440 mm long with a minimum height of
72 mm. By comparison, the dentary of the Giga-
notosaurus holotype is 135 mm deep, and that of
MUCPv-CH-95 (Calvo & Coria 2000) is 138 mm.
Mapusaurus n. gen. is like Giganotosaurus in that
the dentary expands anteriorly to a greater degree
than most other theropods. A flange at the ventral
end of the symphysis emphasizes this expansion.
84 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 8. — Mapusaurus roseae n. gen., n. sp.: A, B, right dentary (MCF-PVPH-108.2); A, lateral view; B, medial view; C, D, left dentary
(MCF-PVPH-108.125); C, lateral view; D, medial view; E, F, left dentary (MCF-PVPH-108.3); E, lateral view; F, medial view. Abbrevia-
tions: f, flange at ventral end of symphysis; ia, inferior alveolar nerve foramen; id, interdental plate; lr, lateral ridge; mg, Meckelian
groove. Scale bar: 10 cm.
A B
C
D
E
F
lr
lr
id mg ia f
mg
lr
id mg
e fact that it is present in a small specimen
(MCF-PVPH-108.125) shows that the feature is
not controlled by ontogeny, as it appears to be in
tyrannosaurids where it is present in only the larg-
est specimens of Tyrannosaurus rex. It is not known
whether this flange is present in Carcharodontosaurus,
and it is not present in Acrocanthosaurus (Currie
& Carpenter 2000). In MCF-PVPH-108.3, the
dorsoventral expansion at the front of the dentary
is 18% higher than it is at the level of the eighth
alveolus. In MCF-PVPH-108.125 (Fig. 8C, D),
the upper margin at the front of the dentary is
broken externally, but medially the front of the
jaw is about 24% deeper than minimum dentary
height. In comparison, dentary height increases
anteriorly in Giganotosaurus by 33%. Acrocantho-
saurus (Currie & Carpenter 2000) and other large
theropods also have dentaries that increase in height
between mid-length and the front, but the increase
rarely amounts to much more than 10%.
e lateral surface of the large dentary of Mapu-
saurus n. gen. is not as rough as that of Gigano-
tosaurus, but is more textured than that of the
juvenile. ere is a prominent lateral longitudinal
ridge that extends from the level of the third tooth
to the posterior end of the dentigerous part of the
dentary. ere is a row of foramina above the ridge
as in most theropods. Unlike Sinraptor, Allosaurus
and most other theropods, however, the foramina
do not become more dispersed posteriorly. Each
foramen is positioned between a pair of tooth
sockets, just as they are in Giganotosaurus. ere are
significant differences between these two animals
on the medial surface of the dentary, however. e
interdental plates are fused in both genera, but are
only about half the height in Mapusaurus n. gen.
e Meckelian groove is shallow in both, but is
positioned higher in Mapusaurus n. gen. (52% of
the height from the bottom in the juvenile, 38%
in the adult) than Giganotosaurus (31%). Both of
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A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
F
IG
. 9. — Mapusaurus roseae n. gen., n. sp., left splenial (MCF-
PVPH-108.179): A, medial view; B, lateral view. Abbreviations:
amf, anterior mylohyoid foramen; iar, infra-angular ridge; imf,
internal mandibular fenestra. Scale bar: 10 cm.
FIG. 10. — Mapusaurus roseae n. gen., n. sp., right surangular
(MCF-PVPH-108.15): A, lateral view; B, dorsal view. Abbrevia-
tions: 1, fossa for (M.) adductor mandibulae externus; ar, adduc-
tor ridge; qc, quadrate cotyle; rp, retroarticular process. Scale
bar: 10 cm.
A
B
imf
amf
imf iar
A
B
qc
rp 1ar
qc
rp ar
these characters may be related to absolute size or
ontogeny. e exit for the symphysial ramus of
the inferior alveolar nerve (Fig. 8D) opens at the
front of the Meckelian canal in Mapusaurus n. gen.,
Giganotosaurus (MUCPv-CH-1), Allosaurus (Mad-
sen 1976a), Sinraptor (Currie & Zhao 1993) and
other theropods.
e third to 10th alveoli, identified by comparison
with the dentary of Giganotosaurus (MUCPv-CH-
1), are preserved in MCF-PVPH-108.2 (Fig. 8B),
and their dimensions suggest they contained large
teeth. e anteroposterior diameter of each al-
veolus is about 40 mm, which is the same size as
in the holotype of Giganotosaurus. Although the
front of the juvenile jaw is damaged, nine alveoli
are present. is suggests that Mapusaurus n. gen.
had about 15 dentary tooth positions compared
with the complete dentaries known in the holotype
specimen of Giganotosaurus.
One large right splenial (MCF-PVPH-108.179)
was collected (Fig. 9). Although some of the thin-
ner edges are incomplete, the specimen is 525 mm
long. It is a relatively thin, curved plate of bone,
concave laterally and almost flat medially. e
ventral margin has a gentle, sigmoidal curvature
in lateral view, whereas that of Allosaurus is almost
straight (Madsen 1976a). e posterior margin is
emarginated to form the anterior border of the
internal mandibular fenestra, which is positioned
far forward (44% of the total length) from the
back of the splenial. e ventral margin of the
bone thickens posterolaterally to form a promi-
nent ridge that contacts the medial surface of the
dentary and cradles the anterior end of the angular
(Fig. 9). e splenial does not wrap around the
ventral margin of the dentary as in Herrerasaurus
(Sereno & Novas 1993), Ceratosaurus (USNM
4735), and dromaeosaurids (Currie 1995). e
anterior mylohyoid foramen (Meckelian canal)
is completely surrounded by the splenial and is
positioned above the dentary contact (Fig. 9A) like
in Sinraptor (Currie & Zhao 1993). In contrast,
the mylohyoid opening in Allosaurus, Monolopho-
saurus and tyrannosaurids is positioned relatively
lower, passes through the ridge that contacts the
dentary, and is often a ventrally open slot rather
than a foramen. e anteroposterior diameter of
the foramen is relatively small (21 mm), as in all
theropods except tyrannosaurids.
A partial right surangular (MCF-PVPH-108.15)
is known from a small individual of Mapusaurus
n. gen. (Fig. 10). It is similar to the surangular of
86 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 11. — Mapusaurus roseae n. gen., n. sp., left prearticular
(MCF-PVPH-108.139): A, medial view; B, lateral view. Abbrevia-
tions: mfm, mandibular fenestra margin; pc, prearticular contact.
Scale bar: 10 cm.
A
B
mfm
mfm
pc
Giganotosaurus (MUCPv-CH-1) in all respects.
e surangular formed most of the lateral cotyle
of the articulation with the quadrate, and extended
posteriorly to participate in the lateral margin of
the short retroarticular process (Fig. 10). Antero-
laterally, the surangular formed a broad, shelf-like
ridge, the dorsal surface of which was a wide, deeply
concave fossa for insertion of the (M.) adductor
mandibulae externus (Fig. 10A) as in Giganotosau-
rus, Acrocanthosaurus and Tyrannosaurus. Below
the ridge, the surangular sloped ventromedially
at a higher angle than almost all theropods other
than Giganotosaurus (MUCPv-CH-1) and Car-
notaurus (MACN-CH 894). In most theropods,
the surangular tends to be almost vertical beneath
the lateral “adductor ridge”, which is rarely so
prominent (Fig. 10A). e result is that the ven-
tromedial edge of the surangular is positioned
directly under the middle of the jaw articulation.
ere is a shallow canal that extends anteromedi-
ally beneath the adductor ridge to enter the small
posterior surangular foramen (Fig. 10A).
e angular is represented in the collection by a
single fragment from the right side (MCF-PVPH-
108.7). e bone is strengthened by a thick margin
that formed part of the ventral edge of the mandible.
ere is a shallow, posteromedial groove along this
margin for the prearticular contact, which tapers
posteriorly as the bone thins and is replaced by the
prearticular on the ventral margin of the jaw.
e central part of a left prearticular (MCF-
PVPH-108.139) was recovered from the Mapusaurus
n. gen. bonebed (Fig. 11). On the lateral surface,
the ventral ridge is grooved for its contact with the
angular (Fig. 11B). is groove is oriented postero-
dorsally, showing that the prearticular would have
had limited exposure in lateral view posteriorly.
e features preserved suggest that the bone is
conservative and is not significantly different from
the prearticulars of Allosaurus (Madsen 1976a) and
Sinraptor (Currie & Zhao 1993).
Teeth
Teeth with crowns and roots are scattered throughout
the quarry. ey are relatively flat, narrow blades
(Table 2) that are similar to the teeth of other car-
charodontosaurids (Sereno et al. 1996; Novas et al.
1999; Vickers-Rich et al. 1999). MCF-PVPH-108.8
(Fig. 12A) seems to be an anterior right dentary
tooth. MCF-PVPH-108.9 (Fig. 12B) is close in
size but has a taller but narrower crown. It seems
to have been a mid-dentary tooth from the right
side. Both anterior and posterior carina extended to
the base of the enameled crown. Two other teeth,
MCF-PVPH-108.10 (Fig. 12C) and MCF-PVPH-
108.103, are shorter but come from the backs of
the jaws of large individuals. e smallest tooth has
12 denticles per 5 mm, whereas the next smallest
tooth has 10 denticles per 5 mm on anterior and
posterior carina. ere are eight to nine denticles per
5 mm in the larger teeth (Table 2), which compares
well with Giganotosaurus and Carcharodontosaurus.
ese are much larger than the denticles in large
Acrocanthosaurus teeth (Currie & Carpenter 2000)
where there are 13 to 15 serrations per 5 mm.
e anterior carina of the anterior dentary tooth
(MCF-PVPH-108.8) is lingual in position to the
midline (on the vertical plane passing through the
long axis of the cross section) of the tooth. In more
posterior teeth (MCF-PVPH-108.9, -108.10), the
anterior carina follows the midline. e posterior
carina of the anterior dentary tooth twists labial to
the midline. However, when the anterior dentary
87
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FIG. 12. — A-D, Mapusaurus roseae n. gen., n. sp.: A, tooth (MCF-PVPH-108.8) in labial view; A’, close up of posterior denticles and
enamel crenulations of MCF-PVPH-108.8; B, tooth (MCF-PVPH-108.9) in labial view; C, tooth (MCF-PVPH-108.10) in labial view; D,
tooth (MCF-PVPH-108.9) in posterior view; E, Giganotosaurus carolinii, tooth (MUCPv-CH-1) in posterior view. Scale bar: 10 cm.
AB
A’
C
D E
tooth was in the jaw, the tooth was oriented so
that the plane passing through the anterior and
posterior carina was parallel to the sagittal skull
plane. Farther back in the jaws, the carinae coin-
cide with tooth midlines and both are parallel to
the sagittal skull plane. When viewed anteriorly
or posteriorly, a Mapusaurus n. gen. tooth has a
flattened S-shaped curvature such as is also seen
in Giganotosaurus (Fig. 12D, E). When the crown
exits the alveolus, it is curving labially. But towards
the tip, it curves lingually. e carinae describe the
same crown curvature.
Individual serrations are wider (labiolingually)
than they are dorsoventrally long, but the dispar-
ity is not nearly as great as it is in tyrannosaurids.
Blood grooves, similar to those of tyrannosaurids
(Currie et al. 1990), extend onto the surface of the
tooth from between the bases of most denticles.
Crenulations (wrinkles, undulations) in the enamel
curve towards the posterior denticles on the labial
surface of MCF-PVPH-108.8, but are not present
in the other teeth. Similar arcuate crenulations are
characteristic of Carcharodontosaurus (Sereno et al.
1996), Giganotosaurus (MUCPv-CH-1) and other
theropods attributed to the Carcharodontosauridae
(Chure et al. 1999). ey are not present in the
teeth of Acrocanthosaurus (NCSM 14345). However,
wrinkles in the enamel are also present in isolated
88 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 13. — Mapusaurus roseae n. gen., n. sp., axis neural arch (MCF-PVPH-108.83): A, anterodorsal view; B, posteroventral view; C,
lateral view. Abbreviations: ep, epipophysis; nc, roof of neural canal; ns, neural spine; po, postspinal basin; pre, prespinal lamina; se,
spinoepipophysial lamina. Scale bar: 10 cm.
AB C
ns
se ep
pre
po
nc
ns
se
po
ep
ns
theropod teeth from around the world, including
those of tyrannosaurids (Currie et al. 1990), so their
taxonomic significance is presently unclear.
Vertebrae
Measurements of MCF-PVPH-108.83, the neu-
ral arch of an axis, show it is about the same size
as that of the Giganotosaurus holotype. e axi-
al neural arch of Mapusaurus n. gen. (Fig. 13) is
morphologically similar to that of Giganotosaurus
(MUCPv-CH-1), and to a lesser extent Sinraptor.
e neural arch inclines posterodorsally as in most
carnosaurs. Anteriorly it does not extend beyond
the anterior zygapophyses as it does in forms like
Carnotaurus and Ceratosaurus. e epipophysis is
more prominent than it is in Allosaurus (Madsen
1976a) and Acrocanthosaurus (Harris 1998), but is
relatively shorter than that of Sinraptor (Fig. 13).
e conical, slightly curving epipophysis tapers
distally, unlike the broader, tab-like epipophysis
of Giganotosaurus. e neural spine is incomplete
distally, but seems to be somewhat longer and more
gracile than that of Giganotosaurus. e neural
spine of Mapusaurus n. gen. is connected to the
epipophysis by a well developed spinoepiphyseal
lamina with a shallowly emarginated posterior
edge (Fig. 13A, B). Acrocanthosaurus and Allosaurus
lack these laminae and have stronger separations
between neural spines and epipophyses. e neural
spines of these latter animals are taller and more
expanded distally than in Giganotosaurus and likely
in Mapusaurus n. gen. e posterior zygapophyses
join on the midline, forming a V-shaped shelf below
a deep depression (postspinal basin) at the base of
the neural spine (Fig. 13B). In contrast, the pos-
terior zygapophyses of Giganotosaurus are separate
and the depression is open ventrally to the margin
of the neural canal. e prespinal lamina on the
midline of MCF-PVPH-108.83 is shallower and
less elaborate than in Giganotosaurus.
e neural arch of a large mid-cervical (MCF-
PVPH-108.90) is poorly preserved. e complete
neural spine is low (60 mm anterior to the epipo-
physis) and relatively long (120 mm posterior to
the prespinal basin). e dorsal margin is remark-
ably sharp, a condition not reported in any other
large theropod. Equivalent sized vertebrae from the
holotype of Giganotosaurus have taller and much
wider neural spines. e anterodorsal length of
the spine is similar to the conditions in Allosaurus
and Sinraptor, but the height is more reminiscent
of the condition described for abelisaurids (Bona-
parte 1991). e epipophyses of this vertebra are
incomplete, but an isolated cervical epipophysis
(MCF-PVPH-108.162) has the same claw-like
shape as that of the axis.
MCF-PVPH-108.82 (Fig. 14) is probably one
of the cervicodorsal (11th to 13th presacrals)
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FIG. 14. — Mapusaurus roseae n. gen., n. sp., cervicodorsal vertebra (MCF-PVPH-108.82): A, anterior view; B, posterior view; C,
right lateral view. Abbreviations: dp, diapophysis; hp, hyposphene; idl, infradiapophysial laminae; iprf, infraprezygapophysial fossa;
iprl, infraprezygapophysial laminae; nc, neural canal; ns, neural spine; pc, pleurocoel; pp, parapophysis; prz, prezygapophysis; pz,
postzygapophysis. Scale bar: 10 cm.
AB C
ns
dp
prz
iprf
nc iprl
pp
ns
pz
hp
pp
nc
prz
idl
pc
vertebrae because the parapophysis spans the
neurocentral suture and the centrum has a hy-
papophysis. As preserved, it is 390 mm in total
height, and the neural arch is 227 mm measured
from the bottom of the neural canal (Fig. 14A, B).
e anterior zygapophyses meet on the midline
and there is no hypantrum (Fig. 14A). A robust
shelf joins the prezygapophysis to the diapophysis.
Below their V-shaped contact is a pair of ridges
(infraprezygapophyseal laminae) that extend to
the lateral margins of the neural canal. e ante-
rior face of the neural arch is shallowly excavated
lateral to each of these ridges. e width across
the diapophyses would have been 310 mm. e
opisthocoelic centrum is 87 mm long (excluding
the ball-like anterior intercentral articulation), and
on the posterior side is 174 across and 15 mm high
(Fig. 14B). e neural arch is broad, and anteriorly
is 150 mm across at the level of the neural canal,
which has a diameter of 38 mm. e width across
the anterior zygapophyses is 80 mm, and the in-
clined articular surface of the prezygapophysis is
100 mm. A relatively thick lamina connects the
prezygapophysis to the parapophysis (Fig. 14C).
Two infradiapophyseal laminae diverge ventrally,
one converging with the posterodorsal corner of
the centrum and the other with the parapophysis.
A large infraprezygapophyseal fossa penetrates deep
into the interior of the neural arch (Fig. 14A). e
infradiapophyseal fossa also seems to extend into the
core of the bone. It is 150 mm across the posterior
zygapophyses, and each articular facet is 68 mm
across and 32 mm anteroposteriorly. e medial
margin of each facet turns ventromedially to form
the hyposphene (Fig. 14B). A medial ridge extends
from the hyposphene to the top of the neural canal,
whereas a second, more lateral ridge ends at the
dorsolateral corner of the neural canal. ese two
ridges are separated by a shallow concavity. A more
lateral, relatively short ridge is the supplementary
infrapostzygapophysial lamina, anterior to which
is a pneumatic fossa. Each side of the centrum has
two pneumatopores posteroventral to the dorso-
ventrally elongate parapophysis. ere is a strong,
sharp ventral keel (hypapophysis), almost 2 cm
high, along the midline of the centrum.
90 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 15. — Mapusaurus roseae n. gen., n. sp., dorsal vertebra (MCF-PVPH-108.84): A, anterior view; B, lateral view; C, posterior
view. Abbreviations: aip, anterior infraprezygapophysial fossae; asd, anterior spinodiapophysial lamina; hp, hyposphene; hy, hypan-
trum; ns, neural spine; pf, postspinal fossa; prf, prespinal fossa; prz, prezygapophysis; psd, posterior spinodiapophysial lamina; pz,
postzygapophysis. Scale bar: 10 cm.
ABC
ns
prf
prz
aip
hy
asd
ns
psd
pz
hp
ns
pf
e dorsal neural spines are relatively tall, and
incline somewhat posteriorly. In MCF-PVPH-
108.84 (Fig. 15), the entire arch of a mid-dorsal is
preserved. ere are anteriorly facing, deep circular
fossae (infraprezygapophyseal fossae) beneath the
prezygapophyses (Fig. 15A). ere are infrapost-,
and infradiapophyseal fossae separated by thin
laminae that converge dorsally at the transverse
process (Fig. 15B). Above the transverse processes,
both sides of the neural spine are deeply excavated
and are bordered by anterior and posterior spino-
diapophyseal laminae (Fig. 15B). ere are also
excavations (prespinal and postspinal fossae) in
the base of the neural spine between the prezyga-
pophyses and the postzygapophyses (Fig. 15A, C).
e neural spine is tall (410 mm in MCF-PVPH-
108.84; 490 mm in -108.85) and rectangular in
side view (the minimum anteroposterior length of
the spine at midheight in MCF-PVPH-108.84 is
78 mm, but the spine expands distally to 95 mm;
the same measurements are 92 and 108 in MCF-
PVPH-108.85). e anterior, posterior and distal
margins of the neural spine are transversely thick,
whereas the central region of the blade is trans-
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FIG. 16. — Mapusaurus roseae n. gen., n. sp., sacral centrum (MCF-
PVPH-108.209): A, anterior view; B, lateral view. Abbreviations:
nc, neural canal; pc, pleurocoel. Scale bar: 10 cm.
A
B
nc
pc
versely thin. In cross section, the neural spine has
the shape of an I-beam (the thicker parts being
the reinforced, rugose areas of attachment for the
interspinous ligaments). e forward projecting
prezygapophyses are relatively small, and are sepa-
rated by a deep hypantrum. e articular surfaces
are oriented dorsally and slightly laterally, and are
almost horizontal. e distance between the lateral
margins of the posterior zygapophyses is 100 mm
in MCF-PVPH-108.84. ere is a deep (46 mm),
blade-like hyposphene that projects posteriorly to
at least the same level as the postzygapophyses.
Posterior dorsal centra of Mapusaurus n. gen. are
amphiplatyan. MCF-PVPH-108.80 is 165 mm
long, 205 mm wide (anterior end) and 215 mm
tall (from the floor of the neural canal). ere is a
large (60 mm long by 45 mm tall), deep pleurocoel
on each side of the centrum, each of which may
be divided into two smaller pneumatopores as in
Giganotosaurus (MUCPv-CH-1) and Carcharodon-
tosaurus (Russell 1996).
Two unfused, sacral centra (MCF-PVPH-108.89,
-108.209) were recovered from relatively young
animals. Both are transversely narrow, a feature
emphasized by crushing. MCF-PVPH-108.209
(Fig. 16) is the first sacral centrum, and has an ante-
rior intervertebral articulation that is taller (150 mm)
than broad (approximately 120 mm) (Fig. 16A).
e posterior face does not expand much laterally
or ventrally, is much narrower than the anterior
articular surface, and has a roughened surface for
contact with the second sacral. At midlength, the
sacral is 43 mm wide, and the ventral surface is
broadly convex in section. A small contact surface
for the first sacral rib is found on the anterodorsal
corner of the centrum, and a large (49 mm) con-
tact surface for the second sacral rib is found on
the posterodorsal corner of the centrum. e flat
floor of the neural canal is 116 mm long, 20 mm
wide anteriorly and 9 mm wide in the middle. e
floor of the intervertebral (conjunction) foramen
passes anterolaterally across the top of the second
sacral rib contact as in Allosaurus (Madsen 1976a).
ere is a small round pleurocoel positioned near
the anterodorsal corner of each side of the centrum
(Fig. 16). MCF-PVPH-108.89 is another unfused
sacral centrum, possibly the fifth that is 135 mm
in anteroposterior length. e dorsolateral surface
is depressed, contains two shallow pits, and has
no pleurocoels.
Numerous caudal vertebrae were recovered
(Fig. 17). e transverse processes of an anterior
caudal vertebra (MCF-PVPH-108.81) extend later-
ally and somewhat posteriorly for 210 mm (Fig. 17A-
D). e transverse process is 64 mm long at the
base and expands distally to more than 92 mm
(Fig. 17C). e neural spine is 185 mm tall and
94 mm anteroposteriorly at the base (Fig. 17A, B, D).
92 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 17. — Mapusaurus roseae n. gen., n. sp.: A-D, anterior caudal vertebra (MCF-PVPH-108.81); A, posterior view; B, anterior view;
C, dorsal view; D, left lateral view; E-H, mid-caudal vertebra (MCF-PVPH-108.76); E, right lateral view; F, anterior view; G, dorsal
view; H, posterior view; I-L, mid-caudal vertebra (MCF-PVPH-108.78); I, anterior view; J, posterior view; K, dorsal view; L, right lat-
eral view; M-O, mid-caudal vertebra (MCF-PVPH-108.75); M, dorsal view; N, right lateral view; O, posterior view; P-R, mid-caudal
vertebra (MCF-PVPH-108.205); P, anterior view; Q, dorsal view; R, left lateral view. Abbreviations: ans, accessory neural spine; nc,
neural canal; ns, neural spine; pb, postspinal basin; prb, prespinal basin; prz, prezygapophysys; pz, postzygapophysys; tp, trans-
verse process. Scale bar: 10 cm.
AB
C
D
E F G H
I J K L
M
N O
P
Q
R
tp
pz
ns
tp
ns
pz
pz
pz
tp
ns prz ns tp
nc
prz
tp ns
prz
pz
ns
pz
nc
tp
ns prbprz pb ns
tp
pz prz prb
tp
ns
pz
pz
ns
prz
tp
prz
ns
pz ns prz
tp
pz
ns
tp
pz
nc
ns
ans
nc
prz
prz ans
ns
prz ans ns
pz
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FIG. 18. — Mapusaurus roseae n. gen., n. sp.: A-D, distal caudal vertebra (MCF-PVPH-108.79); A, anterior view; B, posterior view;
C, left lateral view; D, dorsal view; E-H, distal caudal vertebra (MCF-PVPH-108.247); E, right lateral view; F, posterior view; G, dorsal
view; H, anterior view. Abbreviations: as in Figure 17 and c, centrum. Scale bar: 10 cm.
AB
C
D
E F GH
ns
prz
c
ns
pz
c
ns
ans
prz pz
prz
ans ns
pz
pz
ns
prz
tp
prz ns
ns tp
prz
prz
It is rectangular in side view and inclines slightly
backward. e postzygapophysial articular facets
are oriented lateroventrally, diverging at an angle of
75°. e centrum (about 140 mm long, 115 mm
wide and 115 mm tall) has a shallow dorsolateral
depression, but there is no evidence of pleurocoels.
e neurocentral suture is fused.
e mid-caudals (MCF-PVPH-108.75, -108.76)
have long and low neural arches. In MCF-PVPH-
108.76 (Fig. 17E), the neurocentral suture is ap-
parently not completely fused, even though it came
from an individual that was significantly larger than
MCF-PVPH-108.75 (an unfused, isolated neural
arch). e horizontal transverse processes project
posterolaterally, and expand slightly distally in MCF-
PVPH-108.75 (Fig. 17M). e neural spine is a long,
low ridge that bifurcates anteriorly to connect with the
prezygapophyses. e articular facets of the prezyga-
pophyses face inward and do not extend anteriorly
beyond the centrum (Fig. 17F). e postzygapo-
physes are anteroposteriorly short, and the articular
facets face outward and down, diverging from each
94 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 19. — Mapusaurus roseae n. gen., n. sp., right scapula (MCF-PVPH-108.50); A, lateral view; B, medial view. Abbreviations: ap,
acromial process; g, glenoid cavity. Scale bar: 10 cm.
A
B
ap
ap
g
other at an angle of 105° (Fig. 17H). e centrum
of MCF-PVPH-108.76 is 165 mm long, 116 mm
wide anteriorly, and 100 mm high posteriorly.
MCF-PVPH-108.205 (Fig. 17P-R) is a more dis-
tal caudal than MCF-PVPH-108.247, although it
comes from a much larger individual. It is 120 mm
long, and posteriorly is 65 mm wide and 75 mm
high. e neural spine is relatively high posteriorly,
but continues anteroposteriorly as a thin ridge.
ere is a low, accessory neural spine (Fig. 17R)
on the anterior end of this ridge as in Acrocantho-
saurus (Harris 1998; Currie & Carpenter 2000),
Sinosauropteryx (Currie & Chen 2001) and other
theropods. In the position where more anterior
caudals have transverse processes, this vertebra has
only a ridge. e articular surfaces of the centrum
are almost triangular in outline.
e most distal caudal, MCF-PVPH-108.79
(Fig. 18), has a 97 mm long centrum with a poste-
rior intervertebral articulation that is 47 mm wide
and 45 mm high. e outline of the centrum is
almost rectangular in posterior view (Fig. 18B).
e neural spine (Fig. 18A-C) is low (39 mm from
the roof of the neural canal to the highest point).
ere is a distinct anterior accessory neural spine
that extends 25 mm above the roof of the neural
canal (Fig. 18C). e prezygapophyses project
anterodorsally beyond the centrum. e articular
surfaces face mostly medially. e postzygapophy-
ses are posteriorly elongate, and converge distally.
eir articular facets face laterally and slightly
ventrally. MCF-PVPH-108.247 (Fig. 18E-H) is
a small distal caudal whose centrum is 44 mm
long, 22 mm wide and 20.5 mm high (39 mm
high including the neural spine). ere is a flat,
blade-like neural spine, triangular in lateral aspect,
and tallest in the posterior half of the vertebra
(Fig. 18E). It continues anteriorly as a low ridge
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FIG. 20. — Mapusaurus roseae n. gen., n. sp., right coracoid (MCF-
PVPH-108.71): A, lateral view; B, medial view. Abbreviations: cf,
coracoid foramen; g, glenoid cavity. Scale bar: 10 cm.
A B
gg
cf
cf
between the bases of the prezygapophyses. e
anterior zygapophyses are well separated from
each other, but extend anterior to the intercentral
articulation (Fig. 18E, H). e postzygapophyses
are short and close to the midline. e vertebra
has a small but conspicuous transverse process
(Fig. 18E, G). Ventrally the centrum is convex in
section at midlength, but has a shallow midline
groove on either end close to the facets for the
haemal arches.
MCF-PVPH-108.97 and -108.210 are the heads
of chevrons, each showing a complete bar across
the top of the haemal canal. e shafts were dorso-
ventrally elongate, and below the intervertebral
articulations, each side of the haemal arch has a
short anterior and short posterior extension.
Ribs
Hundreds of rib fragments and a few full ribs
have been found in the quarry. ey do not seem
to differ significantly in any way from the ribs of
Allosaurus (Madsen 1976a), Monolophosaurus (Zhao
& Currie 1993), Sinraptor (Currie & Zhao 1993)
and other large theropods. A large anterior dorsal
rib (MCF-PVPH-108.106) has a broad depression
on the posteromedial surface of the web between
the capitulum and tuberculum. A pneumatopore
enters the shaft of the rib from the distal end of
the depression. Pneumatic dorsal ribs have been
reported in Sinraptor (Currie & Zhao 1993). e
ribs (and the vertebrae) suggest that Mapusaurus
n. gen. had a chest that was deeper than wide.
Fragments of gastralia are also common in the
quarry, but there is nothing to indicate any significant
differences from the gastralia of other large theropods.
A typical gastralia fragment, MCF-PVPH-108.230,
has a maximum width of about 30 mm.
Pectoral girdle and limb
A partial right scapula (MCF-PVPH-108.50) of one
of the smaller individuals was recovered (Fig. 19),
along with sections of the shafts of other larger indi-
viduals (MCF-PVPH-108.69, -108.185, -108.187).
It is a long, slender, gently curved element, and the
preserved part is 60 cm long (Fig. 19). It is only
60 mm wide at its narrowest point when seen in
lateral aspect. e glenoid faces as much laterally
as posteriorly, and the articular surface is 60 mm
high and 55 mm wide. e acromial process is pro-
nounced and is sharply offset from the anterodorsal
margin of the scapular blade as in Acrocanthosaurus
(Currie & Carpenter 2000), Allosaurus (Madsen
1976a), Giganotosaurus (MUCPv-CH-1), Sinraptor
(Currie & Zhao 1993) and tyrannosaurids (Maleev
1974). e outer surface of the acromial process
is concave (subacromial depression) next to the
coracoid suture. e scapular blades of Ceratosau-
rus (Madsen 1976a), Carnotaurus (Bonaparte et al.
1990), Edmarka (Bakker et al. 1992), Torvosaurus
(Bakker et al. 1992), and Megalosaurus Buckland,
1824 (Walker 1964) are more robust, and the an-
terior margin grades smoothly into the acromion
process. Unlike Carnotaurus and Aucasaurus, the
scapula and coracoid did not co-ossify in Mapu-
saurus n. gen.
A partial left coracoid (MCF-PVPH-108.71) in-
cludes part of the scapular suture, which is 82 mm
wide (Fig. 20). e coracoid foramen is relatively
small with a diameter of 15.5 mm. It passes pos-
terodorsally through the bone to emerge on the
mesial surface near the scapular suture at the point
where it thins dramatically (Fig. 20B).
One bone (MCF-PVPH-108.116; Fig. 21) may
be a furcula, although it is also possible it is a
96 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 21. — Mapusaurus roseae n. gen., n. sp., furcula (MCF-PVPH-
108.116), ventral view. Scale bar: 10 cm.
pair of gastralia that have fused together (Harris
1998). However, the sigmoidal curvature of the
shaft, the symmetry of the bone overall, and the
lack of a joint or line of fusion medially favors the
former interpretation. As in the furculae of other
theropods (Chure & Madsen 1996; Makovicky
& Currie 1998), each lateral shaft curves in two
planes. In anterior aspect (with the midpoint of the
“V”-oriented posteroventrally), the dorsal margin
of each arm is convex mesially, but becomes shal-
lowly concave distally (Fig. 21). In dorsal view,
the anterior margin is concave proximally, but
becomes convex distally. As preserved, the bone is
310 mm across, but if the left shaft were complete,
the whole bone would have been about 360 mm
across. e maximum dimension of the bone is on
the midline, where it is 40 mm deep. Laterally it
tapers to 12 mm.
Most of a right humerus (MCF-PVPH-108.45)
of Mapusaurus n. gen. was found, lacking only the
bone proximal to the deltopectoral crest (Fig. 22).
In an allosaurid, this would amount to about a
third of the length of the whole bone. Because the
preserved length of the humerus of MCF-PVPH-
108.45 is 210 mm, the bone must have been ap-
proximately 300 mm long. Although humerus
length is highly variable in theropods, there is a
strong correlation between humeral shaft width
and the length of the femur (y= 0.82x – 0.81,
r2 = .92, where y is the logarithm of femur length,
x is the logarithm of humeral shaft width, and r2
is the correlation coefficient). e transverse shaft
width of the humerus of MCF-PVPH-108.45 is
51 mm, and this suggests that the corresponding
femur length for this individual was 1180 mm long.
Two of the femora collected are about this length.
All of this suggests that Mapusaurus n. gen. had a
humerus that was only about a quarter the length
of the femur. Tyrannosaurids, Acrocanthosaurus,
Carnotaurus and Aucasaurus all have short arms
with humeri that are less than a third the length of
the femora. Mapusaurus n. gen., in consequence,
had relatively short arms.
e humerus is relatively robust with a mini-
mum transverse shaft width of 51 mm, and a
distal expansion of 104 mm. e deltopectoral
crest is a large plate-like process that projects
approximately 33 mm from the shaft (Fig. 22A,
B). e crest curves as it rises from the shaft and
twists anteromedially until it is about 80° from the
main axis of the proximal end (Fig. 22E). It rises
at an angle of approximately 40° to the transverse
axis of the distal end. e shaft is relatively short
and robust, and is subcircular (44 by 51 mm) in
cross-section with a midshaft circumference of
156 mm. e entepicondyle is relatively small
but conspicuous (Fig. 22A). e distal end of the
bone has a pair of condyles separated by a shallow
depression (Fig. 22A, C, F), and the features are
poorly defined compared with Acrocanthosaurus
(Currie & Carpenter 2000) and Allosaurus (Gil-
more 1920).
A left radius (MCF-PVPH-108.46) of Mapu-
saurus n. gen. is a relatively massive bone, slightly
expanded in both proximal and distal ends (Fig. 23).
e shaft is almost round in cross section with
a minimum transverse diameter of 27.5 mm.
Proximally, the transversely flattened humeral end
twists posteriorly, likely for pathological reasons
(Fig. 23D). e proximal articular surface has a
smooth, slightly concave facet for the radial condyle
of the humerus (Fig. 23E). e posterior side of
the distal end (Fig. 23B) exhibits a lightly scarred
contact for the ulna. In distal view (Fig. 23F), the
articular surface for the carpus is convex with a
triangular outline.
ere is little available information on the Mapu-
saurus n. gen. manus. MCF-PVPH-108.48 (Fig. 24)
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A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
FIG. 22. — Mapusaurus roseae n. gen., n. sp., right humerus (MCF-
PVPH-108.45): A, anterior view; B, medial view; C, posterior view;
D, lateral view; E, proximal view; F, distal view. Abbreviations: dpc,
deltopectoral crest; en, entepicondyle; hrs, humero-radialis origin
scar; rc, radial condyle; uc, ulnar condyle. Scale bar: 10 cm.
FIG. 23. — Mapusaurus roseae n. gen., n. sp., right radius (MCF-
PVPH-108.46): A, anterior view; B, posterior view; C, lateral view;
D, medial view; E, proximal view; F, distal view. Abbreviation: u,
ulnar contact. Scale bar: 10 cm.
AB
C D
E F
u
A B
C D
E F
dpc
en
uc
rc
hrs dpc
uc rc
dpc
uc rc
dpc
98 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 24. — Mapusaurus roseae n. gen., n. sp., left? proximal
metacarpals (MCF-PVPH-108.48): A, probable ventral view; B,
probable dorsal view. Abbreviations: mc II, metacarpal II; mc III,
metacarpal III. Scale bar: 10 cm.
FIG. 25. — Mapusaurus roseae n. gen., n. sp., probable left manual
ungual (MCF-PVPH-108.14): A, medial view; B, lateral view. Scale
bar: 10 cm.
A
B
mc III
mc III
mc II
mc II
consists of the proximal ends of metacarpals II and
III, which seem to be partially fused proximally.
Unfortunately, they are so weathered that it is dif-
ficult to determine whether they are from the right
or left manus. Metacarpal II is the largest element
(88 mm proximal width, 46 mm shaft diameter),
and is comparable in size with that reported for
Acrocanthosaurus (Currie & Carpenter 2000). In
proximal view, the bone is transversely expanded and
dorsoventrally compressed. e medial side shows
a wide and strong contact for the first metacarpal,
although there are no indications of fusion between
these two bones.
e preserved part of metacarpal III is 46 mm
wide, but most of the details of the proximal ar-
ticular surface are not preserved. e shaft has a
transverse diameter of 35 mm, and is subcircular
in cross-section.
Manual phalanx II-2 is represented by MCF-
PVPH-108.109, which is 80 mm long (shortest
length between lateral margins of the proximal and
distal articulations). e proximal end has a tall,
ginglymoid articulation with near perpendicular
lateral and medial margins. ere are strong at-
tachment areas for ligaments on the medial and
especially lateral surfaces near the proximal end.
e colateral ligament pits are high in position,
close to the extensor surface, and the lateral one
is much larger than the medial. e double distal
articulation is narrower dorsally (21 mm) than
ventrally (37.5 mm), and is oriented more ven-
trally than distally. e transverse plane of the
distal articulation is rotated some 10° medially
when compared with the transverse plane of the
proximal articulation. Effectively this turned the
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A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
FIG. 26. — Mapusaurus roseae n. gen., n. sp.: A, left ilium (MCF-PVPH-108.128), lateral view; B, ventro-posterior fragment of right
ilium (MCF-PVPH-108.181) in ventral view (the picture has been inverted to represent the left side; dashed area represents the internal
projection of the pneumatic diverticulae). Abbreviations: a, acetabulum; bs, brevis shelf; ip, ischiadic peduncle; pb, preacetabular
blade; pd, pneumatic diverticulae; pp, pubic peduncle. Scale bar: 10 cm.
A
B
pb
pp a
ip
bs
pd
tip of the ungual medially in apposition to the
claw of the first digit.
e single manual ungual recovered (MCF-
PVPH-108.14) might be phalanx I-2 (Fig. 25B),
but is closer in shape to II-3 of Allosaurus (Madsen
1976a). It is 135 mm long when measured straight
from the dorsal surface of the proximal articulation
to the tip, or 155 mm when measured along the
outside curve.
Pelvic girdle and limb
Most of the pelvis and hind limb are represented
by well preserved bones.
Several ilia have been collected, the best preserved
of which is MCF-PVPH-108.128, a 1050 mm
long, left ilium (Fig. 26). MCF-PVPH-108.245
includes most of the acetabular and postacetabular
regions of a left ilium from an animal of about the
same size. MCF-PVPH-108.181 represents a larger
animal, although the specimen only includes the
region surrounding the ischial peduncle from the
right side. When viewed laterally, the dorsal mar-
gin is slightly concave above the acetabulum, and
slightly convex towards either end. It has a height
(top of acetabulum to dorsal edge) to length index
of 30, which is comparable to Ceratosaurus and
Torvosaurus (Britt 1991), but is less than that of
Giganotosaurus, in which the H/L index is 36, and
Allosaurus with 37. e preacetabular blade is about
the same height (29 cm in MCF-PVPH-108.128,
-108.245) as the postacetabular ala. However, the
preacetabular blade is short, and in MCF-PVPH-
108.128 it is 17 cm from the anterior margin of
the base of the pubic peduncle, compared with
a postacetabular length of 44 cm behind the is-
chial peduncle. e pre-/postacetabular ratio in
Mapusaurus n. gen. (0.39) is almost the same as
that in the holotype of Giganotosaurus (0.38).
e pubic peduncle is incomplete in all speci-
mens, but as preserved in MCF-PVPH-108.245
is 33% deeper than the ischial peduncle. In all
probability, a complete pubic peduncle would
100 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 27. — Mapusaurus roseae n. gen., n. sp., left ischium (MCF-PVPH-108.165): A, lateral view; B, medial view. Abbreviations: a,
acetabulum; ip, iliatic peduncle; op, obturator process; pp, pubic peduncle; sp, subsidiary process. Scale bar: 10 cm.
A
B
ip
a
pp op sp
a
ip
have been much longer because in Giganotosaurus
it is double the depth. It is longer anteroposte-
riorly than it is wide. e ventral margin of this
region expands medially to form a rudimentary
cuppedicus fossa. e acetabulum is 240 mm
long, and there is a pronounced supra-acetabular
crest as in Abelisaurus, Ceratosaurus, Sinraptor,
Torvosaurus and other large, relatively primitive
theropods. e posteroventral margin of the ilium
is incomplete in all specimens, but seems to have
been squared off as in Allosaurus, Giganotosaurus
and Sinraptor, rather than tapering as in Mega-
losaurus and Torvosaurus (Britt 1991). e brevis
shelf is relatively narrow as in more advanced large
theropods, rather than broad as in Ceratosaurus
(Gilmore 1920) and abelisaurids (Bonaparte et al.
1990). However, it is apomorphic in that the shelf
extends dorsoanteriorly into a broad (55 mm in
MCF-PVPH-108.181, 40 mm in MCF-PVPH-
108.245) excavation into the interior of the ilium.
In MCF-PVPH-108.181, this deep fossa penetrates
140 mm into the ilium, reaching a point above
the middle of the ischial peduncle. Between this
excavation and the base of the ischial peduncle,
there are two shallow but distinct pits (diameters
of 26 and 32 mm) in MCF-PVPH-108.245, and
three (diameters of 20, 29 and 48 mm) in MCF-
PVPH-108.181. ese pits also fall within the
margins of the brevis fossa (Fig. 26B). e deep
excavation suggests the presence of powerful ili-
ocaudalis musculature between the brevis fossa
and the base of the tail, whereas the pits may have
been associated with more lateral caudofemoralis
brevis musculature.
e only substantial portions of Mapusaurus
n. gen. pubes are MCF-PVPH-108.145, which is
a 72 mm section of the shaft from the left side, and
MCF-PVPH-108.148 and -108.149, which are
respectively portions of the proximal ends of right
and left pubes. e iliac suture is teardrop-shaped,
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A new Argentinean carcharodontosaurid
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FIG. 28. — Mapusaurus roseae n. gen., n. sp., left femur (MCF-PVPH-108.203): A, anterior view; B, medial view; C, lateral view; D,
posterior view. Abbreviations: 4th t, fourth trochanter; ag, anterior intercondylar groove; at, anterior (lesser) trochanter; fh, femoral
head; gt, greater trochanter; pg, posterior intercondylar groove. Scale bar: 10 cm.
A B CD
fh
at
ag
fh
at
fh
gt
4th t
pg
160 mm long and 55 mm wide in MCF-PVPH-
108.148. Distolateral to the ischial peduncle there is
a low ridge that defines a posteroventrally oriented
oval depression that may have been the origin of the
pelvic muscles (MCF-PVPH-108.149). e mini-
mum shaft dimensions of MCF-PVPH-108.145 are
7.5 by 10 cm, which is 10% greater than those in
the holotype of Giganotosaurus. is suggests that
the specimen represents the largest individual of
Mapusaurus n. gen. from the bonebed.
ere is one complete (MCF-PVPH-108.165;
Fig. 27) 1010 mm long (measured from the dorsal
edge of the pubic peduncle to the distal end) left
ischium, several proximal heads (MCF-PVPH-
108.95, -108.96), and numerous shaft fragments.
e pubic and ischial peduncles are subequal in size,
and are broadly separated by the acetabular margin.
e head of a right ischium (MCF-PVPH-108.96)
shows there was an almost circular concavity for
contact with the ilium. MCF-PVPH-108.95 is the
head of a left ischium, showing a well developed
obturator process that is separated proximally from
the pubic peduncle by a notch, and ends distally
in another notch. A distinct obturator process
(Fig. 27) is separated from the pubic peduncle by
a notch, as in most advanced theropods including
Acrocanthosaurus, Allosaurus, Gasosaurus, Carcha-
rodontosaurus (Rauhut 1995) and Giganotosaurus.
102 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 29. — Mapusaurus roseae n. gen., n. sp., left tibia (MCF-PVPH-108.68): A, anterior view; B, lateral view; C, posterior view; D,
medial view; E, distal view. Abbreviations: aa, area for ascending process of astragalus; cc, cnemial crest; lt, lateral tuberosity. Scale
bar: 10 cm.
ABCD
E
lt
cc
lt
aa aa
lt cc
cc
e plesiomorphic state for large theropods is a
continuous ventral lamina (the “obturator flangeof
Charig & Milner 1997) and is found in Carnotau-
rus, Ceratosaurus, Dilophosaurus, Monolophosaurus,
Piatnitzkysaurus and Torvosaurus. A ridge continues
distal to the obturator process, and expands into
a smaller subsidiary process, presumably for part
of the origin for adductor musculature (Romer
1966). e ridge continues distally along the me-
dial surface of the shaft, eventually merging with
the posterodorsal margin of the ischium. In the
complete ischium, the minimum shaft diameter is
48 mm and the distal expansion is 129 mm. e
dorsoposterior margin of the shaft is somewhat
convex in lateral view, but because the distal end
expands ventrally, it gives the shaft the appearance
of a relatively strong ventral curvature. In contrast,
the ischium of Giganotosaurus is straight in lateral
aspect. e distal end of the shaft expands gradually
and there is no distinct ischial boot. e expanded
distal end has longitudinal ridges and grooves for
contact with the other ischium, but this pair of
bones did not fuse distally as they do in many large
theropods, including Sinraptor.
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FIG. 30. — Mapusaurus roseae n. gen., n. sp., left fibula (MCF-
PVPH-108.202): A, medial view; B, lateral view. Abbreviation: mf,
medial fossa. Scale bar: 10 cm.
AB
mf
ree complete femora assigned to adult individu-
als (MCF-PVPH-108.44, -108.203, -108.233) and
10 partial femora (MCF-PVPH-108.25, -108.54-
108.57, -108.59, -108.61, -108.64, -108.65,
-108.234) from medium- to large-sized individu-
als are known for Mapusaurus n. gen. (Fig. 28). e
largest of these (MCF-PVPH-108.234) is 1300 mm
long, with a shaft circumference of 455 cm. Using
the formula developed by Anderson et al. (1985),
a conservative weight estimate for this individual
would have been 3000 kg. Like Giganotosaurus and
other carcharodontosaurids, the head of the femur
is angled upwards from the shaft, and rises high
above the wing-like lesser trochanter. is is very
different than in most large theropods where the
head is perpendicular to the shaft and is at almost
the same level as the lesser trochanter. In more
primitive theropods (Ceratosaurus, Dilophosaurus,
Herrerasaurus), the head is inclined at an angle of
less than 90° to the shaft (Fig. 28). ere is a deep
groove on the back of the head near the flattened
medial margin, similar to Sinraptor (Currie & Zhao
1993) and Giganotosaurus (MUCPv-CH-1). ere
is a shallow depression bound by a prominent
ridge between the greater and lesser trochanters in
MCF-PVPH-108.44. Unlike Acrocanthosaurus,
Allosaurus, Sinraptor and other carnosaurs, the
fourth trochanter is a conspicuous ridge next to
the depression for the M. caudifemoralis longus.
is ridge (Fig. 28C) is relatively low compared
with that of Carcharodontosaurus (Stromer 1931),
but is similar in development to that of Giganoto-
saurus (MUCPv-CH-1). e minimum transverse
diameter of the relatively straight shaft of the largest
femur is 150 mm. e distal end of the femur has a
sharply defined distomedial ridge along the medial
margin of the anterodorsal surface similar to Giga-
notosaurus (MUCPv-CH-1), Sinraptor (Currie &
Zhao 1993) and most other carnosaurs. e ridge
bounds the adductor fossa medially. e extensor
groove is pronounced but relatively shallow, and
is continuous with the intercondylar trough of the
distal end, like in Giganotosaurus and unlike most
theropods (Fig. 28D). ere are well developed
distal condyles, the lateral one associated with a
distinct crista tibiofibularis. e floor of the flexor
groove has rugose longitudinal ridges, but lacks
the ridge for cruciate ligaments that is found in
allosauroids.
ree complete (MCF-PVPH-108.58, -108.67,
-108.68) and six partial Mapusaurus n. gen. tibiae
(MCF-PVPH-108.52, -108.53, -108.62, -108.63,
-108.66, -108.73) have been collected from the
Cañadón del Gato bonebed (Fig. 29). e small-
est complete one is 887 mm long, and the largest
is 1075 mm. ey represent a minimum of five
individuals (Table 3). In anterior view, the tibia
104 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 31. — Mapusaurus roseae n. gen., n. sp., right astragalus
(MCF-PVPH-108.70): A, ventral view; B, dorsal view; C, posterior
view; D, medial view. Abbreviations: ap, base of ascending proc-
ess; cn, calcaneal notch; fa, fibular articulation; hg, horizontal
groove; p, pit in base of ascending process; pp, posterior proc-
ess. Scale bar: 10 cm.
A
B
C
D
hg
pp
fa
ap
cn
p
pp
ap
ap pp
fa
cn
flares both medially and laterally at the distal end
(Fig. 28A). e flat, anterior surface for the ascending
process of the astragalus is delimited dorsomedially
by a strong ridge. e tibia has a well developed,
deep cnemial crest oriented anterodorsally from
the shaft (Fig. 29B). e medial proximal head is
higher than the lateral, but as in Sinraptor (Currie
& Zhao 1993) there is little evidence of a posterior
intercondylar groove such as there is in Allosaurus
(Madsen 1976a). e fibular crest is positioned
on the anterolateral corner of the proximal end
(Fig. 29A, C). As in Giganotosaurus (MUCPv-CH-
1), the lateral side of the tibia extends distally farther
than the medial edge (Fig. 28A, C). e distal end
is notched posteromedially for a process from the
astragalus (Fig. 29E).
Four complete fibulae (MCF-PVPH-108.132,
-108.202, -108.196, -108.189) and several partials
(-108.51, -108.220) have been recovered and range
in length from 640 to 860 mm. Although the larg-
est one (MCF-PVPH-108.202) is 2.5 cm longer
than the holotype fibula of Giganotosaurus caroli-
nii, it is more gracile (Fig. 30). e proximal end
is 220 cm wide, and has a shallowly hollow medial
surface. e shaft width is 65 mm, and distal width
is 98 mm, compared with 80 mm and 110 mm in
the holotype of Giganotosaurus carolinii. e distal
end twists so that it sits anterior to the expanded
distal end of the tibia, and probably overlapped the
edge of the astragalus. ere is a rugose thickening
on the anteromedial edge of the proximal end of the
shaft for the interosseum tibiofibulare ligaments as
in Allosaurus (Madsen 1976a), Sinraptor (Currie &
Zhao 1993), and most other carnosaurs.
In most features, the right astragalus of Mapu-
saurus n. gen. (MCF-PVPH-108.70; Fig. 31) is
directly comparable with carnosaurs like Allosaurus
(Madsen 1976a) and especially Sinraptor (Currie &
Zhao 1993). ere is a horizontal groove (Fig. 31A)
across the faces of the posteroventrally oriented
condyles, and a shallow depression at the base of
the ascending process. Laterally, the remnants of a
notch can be seen for a process from the calcaneum.
As in Sinraptor, there is a relatively high process on
the posterior margin of the tibial articulation close
to the medial surface (Fig. 31B, C). is plugged
into a notch on the back of the distal end of the
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FIG. 32. — Mapusaurus roseae n. gen., n. sp., left Metatarsal I
(MCF-PVPH-108.246): A, lateral view; B, medial view; C, distal
view. Scale bar: 1 cm.
FIG. 33. — Mapusaurus roseae n. gen., n. sp.: A-F, right Metatarsal
III (MCF-PVPH-108.32); A, anterior view; B, lateral view; C, pos-
terior view; D, medial view; E, proximal view; F, distal view; G-J,
right Metatarsal IV (MCF-PVPH-108.34); G, anterior view; H, lateral
view; I, posterior view; J, medial view; K-O, proximal end of right
metatarsal II (MCF-PVPH-108.35); K, anterior view; L, lateral view;
M, posterior view; N, medial view; O, proximal view; P, metatarsals
II to IV in proximal view. Abbreviations: a, anterior; p, posterior; l,
lateral; m, medial sides. Scale bar: 10 cm.
A B
C
AB C D
E
F
GHI J
K L M N O
P
l
p
m
a
tibia. Because the tibia is shorter on the medial
side than the lateral, it is not surprising that the
proximodistal thickness of the medial condyle of
the astragalus is thicker than the lateral (48 mm
compared with 30 mm in MCF-PVPH-108.70).
Lateral (and only slightly anterolaterally) to the base
of the ascending process, there is a shallow socket
for the distomedial end of the fibula. Although
the ascending process is not preserved, its extent
is well marked on the distal end of the tibia. Its
upper margin was strongly inclined proximolater-
ally, fitting beneath the ridge on the distal end of
the tibia. In MCF-PVPH-108.70, the ascending
process would have risen at least 10 cm above the
base of the astragalus. is suggests that the overall
height of the astragalus in Mapusaurus n. gen. was
approximately 20% of tibial length, which compares
well with Allosaurus, other advanced carnosaurs,
and basal tetanurans.
e metatarsus of Mapusaurus n. gen. is similar to
those of most carnosaurs, including Acrocanthosaurus,
Allosaurus and Sinraptor. Only one first metatarsal
(Fig. 32) was recovered (MCF-PVPH-108.246). is
one is from the right side, and probably represents a
medium sized individual of Mapusaurus n. gen. e
distal third of the metatarsal is inflected anteriorly
and laterally from the dorsally tapering shaft of the
bone (Fig. 32A, B). e medial colateral ligament
106 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 34. — Mapusaurus roseae n. gen., n. sp.: A, B, left pedal phalanx III-1 (MCF-PVPH-108.23); A, dorsal view; B, medial view; C, D,
pedal phalanx III-2 (MCF-PVPH-108.25); C, dorsal view; D, side view; E-G, pedal phalanx III-3 (MCF-PVPH-108.28); E, dorsal view;
F, side view; G, ventral view; H, pedal ungual (MCF-PVPH-108.198), side view. Scale bar: 10 cm.
AB
C D
EF G
H
pit is shallow, whereas that of the lateral side is deep
and large. e distal phalangeal articulation surface
is deep but narrow (Fig. 32C).
In proximal view, the outlines of the second to
fourth metatarsals (Fig. 33A-O) are fundamentally
the same as in Acrocanthosaurus, Allosaurus, Sinraptor
and other carnosaurs. In more primitive theropods
like Ceratosaurus, the anterior margin of the third
metatarsal is as wide as the posterior margin, and
the contacts with the adjacent metatarsals are flat
rather than sinuous (Gauthier 1986). e third
metatarsal of Mapusaurus n. gen. (Fig. 33E) lacks
the arctometatarsalian condition seen in tyranno-
saurids and other coelurosaurs, and was presumably
relatively shorter.
Phalanges
Eight of the pedal phalanges are represented in the
quarry by more than 18 specimens. Only one of
these (MCF-PVPH-108.198) is an ungual (Fig. 34),
which is asymmetrical and was probably from either
the second or fourth digits.
MCF-PVPH-108.23 is a right pedal phalanx
III-1 (Fig. 34A, B). e proximal articular surface
has a roughly triangular outline, with a flat ventral
border. e articular facet is dorsoventrally concave
and transversely straight. In dorsal view, the proximal
end is more transversely expanded than the distal.
In the deeply grooved ginglymoid, the dorsal edges
of the lateral pits are closer to the midline than the
ventral ones.ere are virtually no extensor or flexor
fossae. MCF-PVPH-108.27 is another phalanx II-2,
although from a slightly smaller individual.
MCF-PVPH-108.26 is another phalanx III-1 of
the right side, although it corresponds to a smaller
individual. e morphology is the same as in the
other specimen, but the attachments are less well
defined.
107
A new Argentinean carcharodontosaurid
GEODIVERSITAS • 2006 • 28 (1)
MCF-PVPH-108.25 is a left phalanx III-2
(Fig. 34C, D). Based on its dimensions, it could
correspond to the same individual as MCF-PVPH-
108.23. e bone is stout and slightly longer than
wide. In lateral aspect, the proximal part is lower
than phalanx III-1. e proximal articular surface
is dorsoventrally concave but transversely flat. Both
extensor and flexor fossae are shallow. MCF-PVPH-
108.24 is another phalanx III-2, although it seems
to correspond to the opposite foot of a slightly
smaller individual.
MCF-PVPH-108.28 is identified as a right
phalanx III-3 (Fig. 34E-G). In proximal view, the
kidney-shaped articular surface is dorsoventrally
concave and transversely slightly convex, with
a shallow, vertical, median keel. In dorsal view,
the proximal end is wider than the distal one.
e ginglymoid is formed by two well defined
condyles, separated by a deep central groove. In
dorsal view, the lateral and medial margins of the
condyles converge towards the midline (Fig. 34E).
e colateral ligament pits open laterally, dorsally
and slightly posteriorly. Ventrally, the flexor fossa
is represented by a shallow depression with poorly
defined borders (Fig. 34G).
MCF-PVPH-108.19 is phalanx IV-1 from the
right foot. e proximal articular surface is roughly
triangular in outline as in Allosaurus (Madsen 1976a).
e bone is stout, and has a distal end slightly wider
transversely than the proximal one. In lateral view,
the proximal half of the phalanx is high. e condyle
occupies almost 50% of the length of the phalanx
and the distal articular surface is shallowly concave
in dorsal view. e medial and lateral margins of
the condyle are expanded slightly and are pierced
by deep colateral ligament pits. In ventral view,
there is a proximal depression for attachment of
the flexor tendon.
Specimens MCF-PVPH-108.18 and -108.22 are
identified as left and right phalanges IV-2, respec-
tively. e sizes of these elements suggest they could
belong to one individual that is about the same size
as MCF-PVPH-108.19. ese phalanges are antero-
posteriorly and transversely subequal in length. e
proximal ends are lower than wide, dorsoventrally
concave and transversely straight. e ginglymoid is
strongly asymmetrical, with the medial side higher
than the lateral. e degree of asymmetry is closer to
the one present in Sinraptor (Currie & Zhao 1993)
than that of Allosaurus (Madsen 1976a). e dorsal
extensor fossa is well defined and anteroposteriorly
narrow. e ventral flexor fossa is rather flat but
transversely extensive. ere is another right phalanx
IV-2 (MCF-PVPH-108.21), which has been identi-
fied as belonging to a smaller individual.
PHYLOGENETIC ANALYSIS AND
DISCUSSION
New carcharodontosaurids (including Carcharo-
dontosaurus, Giganotosaurus, and a new form from
Chubut, Argentina) are in the process of being
described and will be important for consideration
of relationships within the family and in a broader
context. For this and other reasons, a preliminary
analysis of Mapusaurus n. gen. relationships was
conducted within the framework of an existing
phylogenetic hypothesis (Currie & Carpenter 2000).
A matrix of 110 characters (Appendix I) was scored
for Mapusaurus n. gen., of which 37 character states
are unknown (Appendix II). Several features that
were coded as unknown for Giganotosaurus in a
previous analysis (Currie & Carpenter 2000) can
now be established. Character 11 was changed to
reflect the differences in composition of the su-
praorbital shelf (formed mostly by the palpebral
in Carcharodontosauridae, prefrontal-postorbital
in Acrocanthosaurus, and lacrimal-postorbital in
tyrannosaurids). Characters coded as “9” in Currie
& Carpenter (2000) are coded instead as question
marks for use in TNT (Tree analysis using New
Technology) Version 1 (Goloboff et al. 2003).
Wherever there were multiple stages listed before
for some taxa, only the more derived state was listed
in the new analysis.
Using TNT, the implicit enumeration option was
run and the new matrix produced three most parsi-
monious, 238-step trees. With the Nelsen option,
the consensus tree shows an unsolved polytomy at
the Node Carnosauria (Fig. 35), with a consistency
index of 0.601 and a retention index of 0.583. is
shows a monophyletic Carcharodontosauridae,
which in the present analysis is diagnosed by having
108 GEODIVERSITAS • 2006 • 28 (1)
Coria R. A. & Currie P. J.
FIG. 35. — Cladogram depicting the strict consensus tree obtained from the phylogenetic analysis.
Herrerasaurus
Abelisauridae
Tyrannosauridae
Oviraptorosauridae
Dromeosauridae
Allosaurus
Acrocanthosaurus
Sinraptoridae
Monolophosaurus
Carcharodontosaurus
Giganotosaurus
Mapusaurus n. gen.
Maniraptora
Coelurosauria
Tetanurae
Carnosauria
Allosauridae Carcharodontosauridae
Giganotosaurinae n. subfam.
heavily sculptured facial bones (Character 6, which
is convergent with abelisaurids), a supraorbital shelf
formed mostly by the palpebral (Character 11), a
small suborbital process on the postorbital (Character
12, convergent with Monolophosaurus), a lacrimal
recess (Character 13, convergent with allosauroids
and tyrannosaurids), a highly pneumatic braincase
(Character 23), a posteroventrally sloping occiput
(Character 25, convergent with Sinraptor), distally
downturned paroccipital process (Character 26,
convergent with Sinraptor), flat, bladelike maxillary
and dentary teeth with wrinkles in the enamel next
to the serrations (Character 42), cervical vertebrae
with two pleurocoels in a single fossa (Character 52,
shared with Acrocanthosaurus and tyrannosaurids)
and a femoral head angled at more than 9° upward
from the femoral shaft (Character 97).
Mapusaurus n. gen. is clearly nested within
Carcharodontosauridae by sharing Characters 6,
12, 23, 25, 42 and 97. In the current analysis,
two unequivocal features, femur with a weak
fourth trochanter (Characters 102) and a shal-
low and broad extensor groove (Character 103)
suggest a closer relationship between Giganoto-
saurus and Mapusaurus n. gen. than either has to
Carcharodontosaurus. Plesiomorphically, in He-
rrerasaurus, tyrannosaurids, allosaurids and most
theropods, the femur retains a fourth trochanter
as a low but robust ridge. On the other hand, in
primitive theropods like Herrerasaurus the femur
lacks a clear extensor groove on its distal end. In
contrast, carcharodontosaurids bear shallow and
broad grooves, converging in this condition with
some maniraptorans.
Although geographic and temporal distributions
agree with this hypothetical sibling relationship be-
tween the South American taxa, the phylogenetic
evidence is presently weak and awaits the publica-
tion of additional anatomical information and the
discovery of more specimens. With these caveats,
a new monophyletic taxon – Giganotosaurinae
n. subfam. – may be defined as all carcharodonto-
saurids closer to Giganotosaurus and Mapusaurus
n. gen. than to Carcharodontosaurus.
Recently, Novas et al. (2005) briefly described
a new carcharodontosaur from the Aptian of
Chubut Province, Central Patagonia.