AII rights reserved
' .
from
the
Lower
Cretaceous
(Albian)
Tony
DiCroce,
Karl F. Hirsch
Denver
of
of the
in
the
joint
Canada-
Proiect.
of
which
1. New Theropod from the Late Cretaceous of 
  Patagonia   RODOLFO A. CORIA
Abstract
The first theropod is recorded for the Upper Cretaceous Allen Forma-
tion of Argentina. The specimen is composed of a distal right femur and
a complete right tibia, and represents a new taxon. It is characterized by
a femur with a strong and well-developed mediodistal crest, a tibia with
a hook-shaped cnemial crest, and a lateral maleolus twice the size of the
medial one. A low facet for the ascending process of the astragalus and
a fossa on the distal articular surface of the tibia link this new taxon
with other tetanuran South American theropods such as Giganoto-
saurus. The new taxon is part of a dinosaur assemblage composed of 
titanosaurs, hadrosaurs, and ankylosaurs.
Introduction
In the last few years, our knowledge of South American theropods has
increased greatly. One Triassic and several Cretaceous taxa have been
described (Arcucci and Coria 1997, 1998; Coria and Salgado 2000;
Novas et al. in press; Calvo et al. in press). Most of this record is com-
posed of carcharodontosaurids and abelisaurids (Coria and Salgado
1995; Bonaparte and Novas 1985; Bonaparte et al. 1990; Coria and
Salgado 2000). These theropods seem to be the dominant carnivores
in the faunas during the Cretaceous in South American, although there
are a few maniraptoran-related forms as well (Novas 1998; Novas et al.
in press).
2 •  Rodolfo A. Coria
A new, fragmentary, but very peculiar theropod has been found in
the Allen Formation (Campanian-Maastrichtian) of Rio Negro Prov-
ince, Argentina; it represents the first theropod from this strata. The
specimen was collected in the fluvial sandstones of the lower part of the
Allen Formation. Previous dinosaur remains found include titanosaurs
(Salgado and Coria 1993), hadrosaurs (Powell 1987) and ankylosaurs
(Salgado and Coria 1996; Coria and Salgado, in press). The new ther-
opod was collected in late 1980s by a field crew headed by Dr. Jaime
Powell for the Universidad Nacional de Tucumán.
Institutional Abbreviation:  MPCA-PV, Museo Provincial Carlos
Ameghino, Vertebrate Paleontology Collection, Cipolletti, Rio Negro
Province, Argentina.
Diagnosis: same as for the species.
Horizon: Allen Formation, Campanian-Maastrichtian.
Locality: Salitral Ojo de Agua, 40 km south of Roca City, Rio Negro
Province, Argentina.
mediodistal crest; tibia with hook-shaped cnemial crest, lateral maleo-
lus twice the size of medial, asymmetrical distal end.
Description
Femur
Approximately 50% of the distal half of a right femur is preserved
(fig. 1.1). The shaft is slender and apparently slightly sigmoidal (fig.
1.1C). The mediodistal crest is remarkable in that it is unusually well
developed. It extends as a broad, anteromedially projecting lamina (fig.
1.1C,D). This thickened structure connects distally with the anterior
side of the medial condyle (fig. 1.1C). In medial view, the width of the
crest is about the same as the femur shaft itself. In distal view (fig. 1.1E),
the axis of both the medial and lateral condyles slightly diverge poste-
riorly. The internal condyle is larger than the external one. The external
condyle does not show any well-developed condylid because the area is
weathered. Nevertheless, there is a distinct neck dividing the base of the
condylid from the rest of the articular condyle. The condylid was
medially placed with respect to the medial condyle. The anterior inter-
condylar groove is not well developed. Both anterior and distal articu-
lar surfaces are well defined by a transversal ridge.
On the posterior side of the femur, above the posterior intercondy-
lar groove, there is a deep and roughened fossa, probably for a muscle
origin.
Figure 1.1. Quilmesaurus curriei,
anterior, (B) posterior, (C)
views. Scale: 10 cm.
TABLE 1.1 Measurements of the Femur and Tibia of Quilmesaurus  curriei (mm)
Shaft length
Scale: 10 cm.
and (D) anterior views.
Tibia
The tibia is complete, and is long and slender (see table 1.1 for
measurements). Most of the proximal end, which contacted the fibula,
is weathered, including the crista fibularis). The proximal end is anter-
oposteriorly expanded and transversely compressed (fig. 1.2A). The
proximal lateral condyle is placed posteriorly and separated from the
bigger medial condyle by a notch. This notch is deeper and more closed
than in other theropods (e.g., Giganotosaurus  [Coria and Salgado
1995], Sinraptor [Currie and Zhao 1993]). The articular surface for the
femur is quite weathered but it appears to have been more narrow than
in other theropods like Allosaurus,  Sinraptor, Giganotosaurus,  and
Carnotaurus. The distal end (fig. 1.2B) is slightly expanded. The distal
articular surface is narrow anteroposteriorly, and shows a notch on the
articular surface of the medial condyle as in Sinraptor and Giganoto- saurus.
The most conspicuous feature of the proximal end is the morphol-
ogy of the cnemial crest. In lateral view (fig. 1.3A), the anterior end of 
the crest projects upward as in some abelisaurs. The shaft is flattened on
both extensor and flexor sides. In posterior view (fig. 1.3B), the lateral
projection of the cnemial crest may have overlapped the fibula entirely.
In medial view (fig. 1.3C), the distal end of the cnemial crest is notice-
ably expanded, with a distinctive hooklike shape.
In anterior view (fig. 1.3D), the lateral maleolus projects distally
more than the internal maleolus, resulting in an asymmetrical profile.
There is no fusion of the proximal tarsals as in some abelisaurs and
ceratosaurs. The facet for the ascending process of the astragalus in-
dicates that it was low as in Giganotosaurus, Ceratosaurus, and Allo- saurus. The facet for the ascending process is 16% of the tibia length,
similar to Sinraptor (Currie and Zhao 1993), and a new Triassic ther-
opod recently reported (Arcucci and Coria 1997). This low percentage indicates a more primitive condition as compared to 20% in allosaur-
ids and 33% in tyrannosaurids (Molnar et al. 1990). This area for the
ascending process is deep due to the anteroposterior thickness of the internal maleolus.
Discussion
Quilmesaurus  represents a new record for the Cretaceous of South
America, as well as a very unusual theropod with unique features in the knee. The specimen bears several features that place this taxon in the
Theropoda, such as highly pneumatized bone shafts, an expanded
mediodistal crest on the femur, a tibia with a well-developed cnemial
crest, and the distal end of the tibia expanded for a triangular ascending
process of the astragalus.
Quilmesaurus is not a ceratosaur (sensu Rowe and Gauthier 1990)
because the tibia shows no evidence of fusion with proximal tarsals. On
the other hand, it shares having a very well-developed cnemial crest
with Ceratosaurus and Xenotarsosaurus (Martínez et al. 1986; Coria
and Rodríguez 1993), although this feature could be a primitive condi-
tion among the Theropoda. Quilmesaurus also shares with Gigano-
 
tosaurus (Coria and Salgado 1995) and Sinraptor  (Currie and Zhao
1993) the presence of a notch on the distal articular surface of the tibia.
Quilmesaurus is the first record for a theropod in the Allen Forma-
tion, Malarge Group, Neuquén Basin, Argentina. This unit has been
explored for several years and has yielded a diverse dinosaur fauna,
including the titanosaur Aeolosaurus  (Salgado and Coria 1993), a
lambeosaurine hadrosaur (Powell 1987), a possible nodosaurid (Salga-
do and Coria 1996; Coria and Salgado in press b), and dinosaur eggs,
possibly of titanosaurs. This association involves the coexistence of 
both North American and South American forms. Interestingly, the
new form does not show any unquestionable feature related with
Laurasian forms, which would be expected since it was found at the
same levels where North American related fauna is common (e.g.,
hadrosaurs and ankylosaurs). In contrast, it bears many plesiomorphic
characters more similar to typical South American dinosaurs (e.g.,
absence of a well-developed anterior intercondylar groove on femur,
facet for the ascending process of astragalus less than 20% of tibia shaft
length). These features are present in the South American Xenotarso-
saurus,  Giganotosaurus,  Piatnitzkysaurus,  and several undescribed
forms (Coria and Currie 1997; Calvo et al. in press).
Acknowledgments: I thank Mr. Carlos Muñoz for allowing me to
study the specimen under his care. I am indebted to A. Arcucci and L.
Salgado for their comments on early drafts of this chapter, and to Mr. Darren Tanke for his invitation to participate in this book. The illustra-
tions were skillfully made by Aldo Beroisa. Lastly, I thank Dr. Philip
Currie for his steadfast scientific guidance and kind friendship.
References
Arcucci, A. B., and R. A. Coria. 1997. Primer registro de theropoda (Dinosauria—Saurischia) de la Formacion Los Colorados (Triasico Superior, La Rioja, Argentina). Ameghiniana  34: 531.
Arcucci, A. B., and R. A. Coria. 1998. Skull features of a new primitive theropod from Argentina.  Journal of Vertebrate Paleontology, Ab- stracts (suppl. to no. 3) 18: 24A.
Bonaparte, J. F., and F. E. Novas. 1985. Abelisaurus  comahuensis, n. gen., n. sp., Carnosauria del Cretacico Tardo de la Patagonia. Ameghiniana, 21: 259–265.
Bonaparte, J. F., F. E. Novas, and R. A. Coria. 1990. Carnotaurus sastrei, the horned lightly built carnosaur from the Middle Cretaceous of  Patagonia. Natural History Museum of Los Angeles County, Contri- butions in Science 416: 1–42.
Calvo, J. O., D. Rubilar, and K. Moreno. In press. Report of a new theropod dinosaur from Northwest Patagonia. Abstracts 15 Jornadas Argentinas de Paleontología de Vertebrados, Ameghiniana.
Coria, R. A., and P. J. Currie. 1997. A new theropod from the Ro Limay Formation.  Journal of Vertebrate Paleontology, Abstracts  (suppl. to no. 3) 17: 40A.
Coria, R. A., and J. Rodríguez. 1993. Sobre Xenotarsosaurus bonapartei Martínez et al. 1986; un problem tico Neoceratosauria (Novas 1989) del Cretacico del Chubut. Ameghiniana  30: 326–327.
 
New Theropod from the Late Cretaceous of Patagonia •  7
Coria, R. A., and L. Salgado. 2000. A basal Neoceratosauria (Theropoda- Ceratosauria) from the Cretaceous of Patagonia, Argentina. Gaia 15: 89–102.
Coria, R. A., and L. Salgado. In press. South American Ankylosaurs. In K. Carpenter (ed.), The Armored Dinosaurs.  Bloomington: Indiana University Press.
Currie, P. J., and X. Zhao. 1993. A new carnosaur (Dinosauria, Theropoda) from the Jurassic of Xinjiang, People’s Republic of China. Canadian
 Journal of Earth Sciences 30: 2037–2081. Martínez, R., O. Gimènez, J. Rodriguez, and G. Bochatey. 1986. Xeno-
tarsosaurus bonapartei: nov. gen. et sp. (Carnosauria, Abelisauridae), un neuvo Theropoda de la Formacion Bajo Barreal Chubut, Argen- tina. Cuarto Congresso Argentino de Paleontología y Biostratigra-
 phía, Mendoza, Argentina 2: 23–31. Molnar, R. E., S. M. Kurzanov, and Dong Z. 1990. Carnosauria. In D. B.
Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria,  pp. 169–209. Berkeley: University of California Press.
Novas, F. E. 1998. Megaraptor namunhuaiquii,  gen. et sp. nov., a large- clawed, Late Cretaceous theropod from Patagonia.  Journal of Verte- brate Paleontology  18: 4–9.
Novas, F. E., S. Apesteguia, D. Pol, and A. Cambiaso. In press. Un probable troodontido (Theropoda-Coelurosauria) del Cretacico Tardio de Patagonia. xv Jornadas Argentinas de Paleontologia de Vertebratos, Ameghiniana.
Powell, J. E. 1987. Hallazgo de un dinosaurio hadrosaurido (Ornithischia, Ornithopoda) en la Formación Allen (Cretacico Superior) de Salitral Moreno, Provincia de Río Negro, Argentina. Décimo Congreso Geo- logico Argentino, Actas  3: 149–152.
Rowe, T., and J. A. Gauthier. 1990. Ceratosauria. In D. B. Weishampel, P. Dodson, and H. Osmólska (eds.), The Dinosauria,   pp. 151–168. Berkeley: University of California Press.
Salgado, L., and R. A. Coria. 1993. Un nuevo titanosaurino (Sauropoda- Titanosauridae) de la Fm. Allen (Campaniano-Maastrichtiano) de la Provincia de Rio Negro, Argentina. Ameghiniana  30 (2): 119–128.
 
S7. Lucas's
of
L.
to
Allo-
saurus.
Introduction
enormous contribu-
Cope's
it
arrived
in
1903
(Osborn
1,931,\.
10
convex,
the
the
more
anterior
tooth.
The
crown
margin. The
distal serrations
are
more
pronounced
and
the
mesial
anterior extremity,
been considered
lost, Mclntosh
teeth.
be
reconciled.
There
are
two
the
jaw
sent
in
the
B
of
bone
the collections of the AMNH. There
is
no
evidence
trihedrodon. The
that the
carnivorous, appar-
entl,v because
of the
Gllt
(1997,113)
is
clear-
ly
stegosaurian.
that
in
shipment
8.
Thus,
after the Cope collection
part
ol
tibia,
and
1013
is
given
cannot be
in that
u'ork, and
of bones
in
the
United
t09:1.-1.63.
Madsen,
J.
H.,
gigantic
dinosaur.
American
Journal
of
Science,3d
avian brain
the fossil data
element.
Janensch
(1936)
interpreted
neck
mus-
culature
into
opens
of the
the scanning
However, the
direction
tion
is
correct,
utriculus
and
into
tetrapods.
Behind
this
depression
is
papilla
where it formed the lagena, as in extant amniotes. In Carcharodonto-
saurus,
the
of the
opisthotic, and
probably part
septum
to
from
and
24
have separated
basisphe-
would
iocated
posterior
two
fo-
near
the
little
discrete
ana-
ous workers
(Osborn
191,2;JerisonI973).
Hopson
(1979)
more
preserved
nearly
100"/"
ratio
cannot
4000 kg. The
docasts,
That
is,
the
ratio
of
the
dural
medulla oblongata is assumed to be equal
among
assumptions. Hopson
greater
extent than that over the forebrain, but it is unknown if the reiative
ratio
between
of the
are
obtained.
\fith
the
endocast should
clearly
demarcated
regions
within
fossil
endocrania
(Hopson
fossil
have
a
greater
accuracy
the avian cerebral
brain
masses
to
cerebral
mass
increases
bird
brains
increase
in
size,
their
cerebra
increase
at
a
nonavian
fossil
of
UUVP
294.
Figures
of
above,
for Troodon
size. Currie and Zhao
mm. A
the upper and
values
of
33.9
mm
and24.9
mm,
respectively.
The
The resulting volumes were transformed to masses with the same
specific
gravity
used
above.
distance based
on fixed x-values was used to estimate the relationship of each fossii
datum to the
cerebral
with the
independent variable.
occupied
by
the
datum.
The
28
1.o/o
note
up
relationships
more
proximal
position
supports
the
hypothesis
that
as noted
the
bird
regression
from
no doubt reflects its
reflection
of
the
laterally
compressed.
Conclusions
The
avian brain
ear
share
more avian endocranial
the
nonavian
coelurosaurs.
volume
comparison,
Allosaurus
and
Carcharodontoslurus.
These
theropods
do
not
is
also
significantly
the origin
somewhere within
regression.
Clearly
these
career.
bstract
An almost com plete lower jaw of Gallimimu s bullatus reveals new fea-
tures not previously recognized. Medially, it differs from the previous
reconstruction in numerou s details: the splenial does not extend t o the
symphysis and it has a large ventral mylohyoid foramen, the intra-
mand ibular joint indicates tha t separate movement of the anterior part
of the lower jaw w as n ot possible, the prearticular is large and covers
the articular in medial view, the prearticular is not covered by the
splenial anterodorsally, but the two bones have a close fit, and finally
the coronoid and the supradentary are absent.
Introduction
Lower jaws of Late Cretaceous North American ornithomimosaurs
have been known for a long time; Struthiomimus Osb orn 191 7) and
Ornithom imus Parks 193 3) , but were only described from the lateral
side. Osm6lska et al. 19 72 ) described both lateral and medial views of
the Late Cretaceous Gallimimus bullatus from the Go bi Desert, Mo n-
golia. Barsbold later 19 83 ) described the lower jaw of the Late Creta-
ceous Mongolian Garudimimus brevipes in both lateral and medial
view, and Barsbold and Perle 19 84 ) described the lower jaw of the
Middle Cretaceous Harpymimus okladnikovi in medial view. Russell
19 72 ) revised the ornithom imosau rs from th e Late Cretaceous of
western C anad a and erected the genus Drorniceiomirnus for Struthio-
mim us brevetertius an d S. samueli, and figu red lower jaws of D brew-
etertius and D samu eli in lateral view. PCrez-Moreno et al. 19 94 )
described Pelecanimimus polyodon, an Early Cretaceous toothed orn i-
 
The lower jaw of ornithomimosaurs was described by Barsbold
an d Osm6 lska as: slender, tapers slightly forw ard , and is very shallow
for mo st of its length. Th e surangular p ortio n of the m andible is gently
convex dorsally, but the adductor prominence is usually not pro-
nounced. T he external mand ibular fenestra is small and elongate. The
man dibular symphysis is relatively long and inclined caud oven trally
(1990,229) .
A furth er pre par ation of th e juvenile skull of Gallimimus bullatus
described by Osm 6lska et al. (19 72) , provides new data requiring an
emending of the ob servations of O sm6lska e t al. ( 19 72 ), Barsbold
(198 3) and Barsbold and Osm6lska (199 0).
Materials and M ethods
The paper-thin, right lower jaw of Gallimimus bullatus (ZPAL
MgD-LI1) was freed from the skull by careful prepara tion, and partly
embedded in Carb owa x peg 2000. Th is was later dissolved after prepa-
ratio n of the delicate surfaces.
Institutional Abbreviations: RTMP, Royal Tyrrell Museum of Pa-
laeontology, Drumheller, Alberta; ZPAL, Institute of Paleobiology,
Polish Acad emy of Sciences, Warsaw.
escription
The toothless lower jaw is slender and was covered by a horny beak
along its antero dorsal part. The constituent elements fit together per-
fectly and the re does not app ear t o have been movement between them.
Dentary figs.4 .1 , 4 .2 )
Th e anterior on e-third of the dentary w as described as shovel-like
by Osm 6lska et al. (1972 ),because of the laterally curved dorsal b order
of the dentary. The curvature begins abov e the anteriorm ost end of the
splenial. In Mg D- Ill, the symphysed region to the left dentary is miss-
ing. Th e posterolateral p ar t of the de ntary is also missing, but this can
be reconstructed from the impression in the sandstone that covers the
angu lar an d prearticular in lateral view.
In lateral view, the dentary differs from the reconstruction in
Osm 6lska et al. (19 72) . There is a small foramen situated an teriorly.
The posterior border is interpreted t o be more like in othe r ornitho-
mimosaurs by forming the anterior border of the external mandibular
fenestra.
In medial view, the posterior two-thirds of the dentary is covered
by the splenial, the Meckelian groove is deep and extends to the
anterove ntral bo rder of the preserved pa rt. Th e splenial covers most of
the Meckelian groove and fits perfectly with the dorsal and ventral
parts of the dentary. The posterodorsal contact with the surangular is
divided into two sho rt processes, one lateral and one medial. They form
a groove for the insertion of the intram andibu lar process of the sur-
angular. The dorsomedial process of the dentary fits into a shallow
groove in the surangular.
 
the lower jaw and the quadrate of
allimimus bullatus
ZPAL MgD
Splenial figs. 4. 1, 4. 2)
The splenial, only visible in medial view, is roughly triangular in
shape. Contrary to Osmdlska et al. 1972), t does not reach anterior-
ly to the symphysis, but only covers the posterior two-thirds of the
dentary. The bone contains two foramina, the large anteroventral
mylohyoid foramen and a smaller dorsal foramen. The mylohyoid
foramen is surrounded by the splenial, except for a small anterior slit.
Th e posteroven tral p art fits int o a shallow groove in the angular.
Surangular figs.4 .1 , 4 .2)
Th e surangular is the second largest bone of the m andible, w hich
is the usual condition in theropods. It covers the anterior part of the
articular posterolaterally and has a long, partly preserved, ventral
border to the angular. The dorsal part of the intramandibular joint is
covered by the splenial and the prearticular, but as far as can be
determined, it is a normal theropod joint with a process of the sur-
angular t ha t fits between the lateral and medial processes of the den tary
see Hu rum and Currie in press). The surangular has a small anterior
surangular foramen. shallow groove extends anteriorly from the
foramen. The posterior border of the external mandibular fenestra is
reconstructed.
Angular figs.4 .1 , 4 .2)
Th e angular is somewhat broken, but is possible to reconstruct in
lateral view. Th e bone covers the anteroven tral p art of the artic ular and
forms the ventral border of the external mand ibular fo ramen . Th e mo st
ant erior pa rt is covered laterally by the dentary. In medial view, only a
small part is visible between the splenial and the prearticular, where i t
has a shallow groove fo r the splenial.
Figure 4.2 . Schematic drawings of
the lower jaw of Gallimimus
bullatus ZPAL MgD-I/4): A )
Anatomical abbreviations:
a-articular, an-angular,
d-dentary, pa-prearticular,
s-splenial, sa-surangular.
 
Prearticular (figs. 4.1, 4.2)
Th e prearticular is visible in lateral view due to th e pre paration of
the external mandibular foramen and some damage to the dentary. In
the external mandibular foramen, it is possible to see a sha rp ridge o n
the prearticular. In m edial view, the bo ne has an e xtensive anterior pa rt
covering the posterior of the dorsal intramandibular joint, and has a
relatively close fit to the po sterior border of the splenial. Medially, the
posterior part of the prearticular totally covers the articular and ex-
tends to th e posterior end of the retroarticular process. The prearticular
forms the ventral and lateral margins of the ad duc tor fossa.
Articular (figs. 4.1, 4.2)
Only the posterior part of the articular is visible because the
qua dra te still covers the glenoid fossa. In lateral view, the retroarticu-
lar process is relatively short compared to other ornithomimids. The
articular is wide in dorsal view, but is unfortunately covered by the
quad rate. O n the medial side the bone is covered completely by the
prearticular.
Coronoid a nd Supradentary
Th e coronoid and supradentary were never present in the lower
jaw of G allimimus. There is no sign of an attach men t between a cor-
onoid and the surangular or prearticular, a nd no groove for a supra -
dentary on the dorsolateral side of the dentary, as in, for example,
tyrannosaurids (see H uru m and C urrie in press).
iscussion
The shape of the bill in ornithomimosaurs has been under con stant
debate. O sborn (19 17) suggested that the premaxillaries and dentaries
of Struthiomimus altus were sheathed in narrow horny beaks some-
what similar to those of the extant ostrich, Struthio. Russell stated,
The development of a bony vault over the anterior part of the oral
cavity (secon dary pala te) and a transverse axis of flexure in the sku ll
roof anterior to the orbits, together with the general shape of the
muzzle, recall the morphology of the bill in modern insectivorous
birds (1972,
399 410 0). Later, Nicholls a nd Russell (198 5) suggested
a flat herbivo rous beak. Barsbold and Osm 6lska stated, the lower
and up per jaws of ornithom imosa urians did no t form a flattened beak
comparable to that in hadrosaurids, for example. Instead, the beak,
although broad , w as relatively deep rostrally, a t least in these species in
which it was well preserved (19 90 ,244 ).
The mandibles in Ornithomimosauria are best known in Galli-
mimus bullatus and G arudim imus brevipes. They both have a shovel-
like anterior end of the dentary (Osm6lska et al. 197 2). Th e shape of
the dentary in Gallimimus is comparable to that of the front of the
dentary in the com mon seagull (L aru s) and indicates a similar shaped
bill. The seagull-like lower jaw suggests th at G allimimus, like seagulls,
had an opportunistic, possibly omnivorous diet as suggested by Gre-
gory in Osborn 1917.
 
The angular is the most flexible bone of the lower jaw in orni-
thom imosa urs fig. 4.3). Struthiomimus altus has a small angular and
Ornithomimus edmontonensis has a n ang ular covering the articular
nearly to the posterior end of the mandible. T he extent of the angu lar
in Gallimimus is similar to Dromiceiomimus brevetertius.
The anterior expansion of the prearticular in Gallimimus is not
seen in any other theropod, except to some degree in Ceratosaurus
Bakker et al. 198 8). The usual manner, as seen in tyrannosaurids
Hurum and Currie in press), for example, is for the prearticular to
taper into a thin anterodorsal end covering a small portion of the
intram andibu lar joint. The a nterodo rsal area covered by the preartic-
ular in Gallimimus is the same as covered by the prearticular and
coron oid in oth er theropods. Because of the lack of the coronoid this
widening of the anterior po rtion m ight be a secondary specialization to
cover the same area medial to the
adductor fossa. The coronoid and
suprad entary are missing in all theropo ds tha t evolved toothless beaks
ornithomimosaurs and oviraptors), Segnosaurus Perle 19 79) , n Erli-
kosaurus Clark et al. 1 99 4), and in birds. Garudimimus is described
with a peculiar prea rticular th at bo rders the ventral side of the add uc-
tor fossa Barsbold 1983 ; Barsbold and Osm6lska 19 90 ). This is very
different from the more n ormal theropod prearticular in Gallimimus.If
this is not an artifact of preservation, this makes the prearticular of
Garudimirnus more like the struc ture observed in oviraptorids see,
e.g., Barsbold 19 83 , fig. 1 3 ) than in Gallimimus.
In Gallimimus the fit between the p rearticular and splenial is tight
and allows no movement between the anterior dentary splenial) and
posterior pa rt surangular angu lar articular prearticular) of the
mandible. Thero pods like tyrannosaurids Hu rum and Currie in press),
dromaeosaurids Currie 19 95 ) and large theropo ds e.g., Monolopho-
saurus Zh ao and Currie 199 3), have a relatively wide opening between
the prearticular and the splenial. Th e close fit is possibly a plesiomorphy
also observed in Archaeopteryx Elzanowski and Wellnhofer 1996),
Dilop hosa urus wetherilli S yntarsus rhodesiensis Liliensternus Huene
1934), Segnosaurus and Erlikosaurus.
The articular in Gallimimus has a small retroarticular process
compared t o other ornithomimosaurs fig. 4.3). On the medial side the
bone is covered completely by the prearticular, a n unus ual con dition
seen only in Carnotaurus Bonaparte et al. 1 99 0) . The prearticular
covers the medioventral p ar t of the articular an d extends to the poste-
rior end of the lower jaw in Dilophosaurus wetherilli Welles 198 4),
Syntarsus rhodesiensis Raath 1977),Sinraptor Currie and Zhao 1993 ),
Allosaurus Madsen 197 6), and oviraptors Barsbold 198 3).
onclusions
Even though it is peculiar in lacking teeth and th e prearticular is
widened anteriorly, the lower jaw of Gallimimus shows the comm on
theropo d structure.
The following th eropo d plesiomorphic characters ar e recognized
in the low er jaw:
Lower Jaw of Gallimim us bullatus 3 9
 
lower iaw in different ornitho-
mimo;aurs, thk angular
highlighted in black. Struthio-
simple intra-mand ibular joint,
brevetertius, and D. samueli
close fit between the s ~ le n i a l nd vrearticular.
redrawn from Russell 1972);
Garudimimus brevipes redrawn
Suggested apo m orph y of the lower jaw of Gallimimus bullatus is:
from Barsbold 1983); Ornitho-
mimus edmontonensis redrawn
Following Sereno s (19 99 ) phylogeny of dinosaurs, th e lack of cor-
rom
Ornithomimus
onoid and s upraden tary might be an apom orphy for the therizinosaur-
sp. reconstructed from RT P
95.1 10.1, Struthiomimus sp.
ornithom imo saur clade.
from RTMP 96.05.09. Juvenile
Gallimimus bullatus this study).
specimen Gallimimus available for my study and reading an early
~ o to scale.
version of the manuscript. Photographs were taken by Per Aas. The
review by Tho m as R. Holt z Jr. also contributed t o this chapter. This
chap ter has benefited much fro m the hospitality and friendly help of
Phil Currie during my postdoctorate 1998-2000. From my first meet-
ing with P hil in 1 98 8 as a volunteer in Dino saur Provincial Park, to the
field seasons in Argentina an d C anad a in 1 999 , he has always been a
suppo rt and a dear friend. This work w as supported by the Norwegian
Research Council (gran t no. 1228981410).
References
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mim osaur from the Cretaceous of Mongolia. Paleontological Jou rnal
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andrewsi, a Late Cretaceous Segnosaur (Theropod a: Therizino-
saur idae) from Mong olia. American Museum N ovitates 3115: 1-39.
Currie, P. J. 1 99 5. New inform ation on the anatomy and relationships of
Drom aeosaurus albertensis (Dinosauria: The ropo da). Jour nal of Ver-
tebra te Paleontology 1 5 (3): 576-591.
Currie, P. J., and X. Z ha o. 199 3. A new carnosaur (D inosauria, Therop oda)
from the Jurassic of Xinjiang, People's Republic of China. Canadian
Jour nal of Ear th Sciences 30: 2037-2081.
Elzanowski, A., and P. Wellnhofer. 19 96 . Cranial morph ology of A rchae-
opteryx: Evidence from the seventh skeleton. Journal of Vertebrate
Paleontology 16 1):81-94.
Hu ene, F. 1 93 4. Ein neuer C oelosaurier in de r thiiringischen Trias. Paliion-
tologische Zeitschrift 16: 145-170.
Hurum,
J.
H., and P. J. Currie. In press. Th e crushing b ite of tyranno saurid s.
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and tall
plane.
These
specializations
most notable for
most
Ouiraptor
philocera-
South
America
and
Austra-
lia
(Frey
and
Martill
the
group
re-
ankle and
more
forms,
(Currie
1989,1990),andChiro-
Currently, there
Micro-
(Makovicky
th omimus"
el e
Chirostenotes
pergracilis
Currie
(1,989,19971
fusion
also
found
might corre-
Alberta cdnddensis canadensis
their
fragmentary
nature,
these
specimens
cannot
help
(now
Paleontology,
(Cam-
panian,
(2)
a
higher
and
more
Formation
of
it
the
ASC
complex.
MOR
1
107
fusion
and
presumably
represents
an
adult
large
antero-
posterior
2033, and also figure a similar slot
in the type
foramen. Al-
North
type
ol
Caenagnathus
collinsi
(Stern-
berg
Caenagnathus sternbergi
incomplete
remains
elegans.
distal articular surfaces
condyle
of
phalanx
IV-4
 
temporary theropods shows them to be most similar to those of dro-
maeosaurids. Height-width ratios of articular surfaces are similar;
for
0.63
ginglymoid
correspond to
for
the eagle and emu. Although all the above theropods bear a dorsal
pit
just
proximal
to
Broken surfaces
each.
rostenotes
pergracilis
(NMC
8538,
shaft
with a tight contact
fiS.
3).
appears to
preserve
a
have an elongated
in the
is
the
tbdn metdtdrsal III in order to
include MOR
elegans
/MOR
752l,
Elmisaurus
rarw
(MgD-I/1.72
and
very similar and co-occur
(Currie
Summary
saura,
Achelousdurus,
and
sternbergi to the list of theropods
shared by
both the
record
ol
Elmisaurus
elegans
in
tral
plane
but
and turtles
theWorld. NewYork: Simonand
andJ.
R.
Basin,
Sereno,
P.
C.,
C.
Dinosauria.
Nature
361:
64-66.
Smith,
J.
Quarrv
Belly River
Formation of
Alberta. Canadian
and biting strategies of theropod dinosaurs. The majority of theropod
tooth marks reported t o date have been found on herbivorous dinosaur
bones, although som e tyrannosaurid bones with tooth marks have also
been reported. n 19 88 a partial skeleton of the drom aeosaurid Saur
ornitholestes was collected from southern A lberta, Cana da, th at bore
tooth m arks on one dentary. Th e location and morphology of the tooth
marks suggests tha t a theropod possibly a juvenile tyrannosaurid)
included a Saurornitholestes in its diet.
Introduction
Ecological and behavioral aspects of dinosaur research have received
increased interest in recent years Farlow and B rett-Surman 19 97 ;
Currie and Padian 19 97 ), with studies of theropod teeth a nd theropo d
tooth-marked dinosaur bones being used t o determine clues as to the
potential feeding behavior and predator-prey or intraspecific interac-
tions of theropods Abler 199 2, 1999; Chin 1997; Chure et al. 199 8;
Currie and Jacobsen 199 5; Tanke and Currie 1 995 , in press; Erickson
1999; Erickson et al. 1996 ; Erickson and Olson 1 995 ; Fiorillo 199 1;
Jacobsen 1995 , 1997, 19 98; Larson 1999; Mongelli et al. 199 9).
Th e morphology of too th ma rks on a bone can be correlated with
 
size and shape of kn own taxa (Jacobsen 19 95 ). Based on such com-
parisons, tyrannosaurid tooth marks on bone are the most common
and have been identified on a variety of bones of prey, including had-
rosaurids, ceratopsids, and other tyrannosaurids (Erickson and Olson
199 5; Jacobsen 199 5, 199 7; Tanke and Currie 19 98 ). These tyran-
nosaurid bones comprise only 2 of the tooth-marked bones know n
(Jacobsen 199 8) . It is rarely possible to correlate tooth mark s of sm all
theropods t o kn own taxa, probably due to the small size and similar-
ity of denticles on some small theropod teeth (Currie and Jacobsen
19 95 ). Two exceptions include a single ornithom imid caud al vertebra
(TMP85.6.158) that exhibits Saurornitholestes tooth drag marks (Ja-
cobsen 19 95 ), and a partial skeleton of a Troodon (M O R 74 8) with
pun cture m arks (D . J. Varricchio, pers. comm ., 200 0).
In the Dinosaur Park Fo rmation of south ern Alberta, small thero-
pods are rare (C urrie 199 7)and com prise only a small percentage of th e
dinosaur fauna (Brinkman 19 90; Brinkman et al. 1 99 9). Their thin-
walled bones are foun d broken or poorly preserved. Th e discovery of a
partia l skeleton of Saurornitholestes is therefore sign ificant, especially
because it also bears tooth marks.
Institu tion al Abbreviations: TMP, Royal Tyrrell Museum of Palae-
ontology, Drumheller, Alberta; MO R, Museum of the R ockies, Boze-
man, M ontana.
TMP 88.121.39 is a partial Saurornitholestes skeleton collected
from the Cam panian Dinosaur Park F ormation, along the Milk River
in southern Alberta. The ontogeny and anatomy are currently being
stud ied by Drs. P. J. C urrie an d D. J. Varricchio (in prep.). T he speci-
men has been used previously in an atomical studies and relationships
of theropods (Currie 1995; Makovicky 1995; Britt 1993; Xu et al.
19 99 ). The skeleton consists of several cranial elements (including a
left den tary) , right scapula, right coracoid, right hum erus, several ribs,
gastralia, right femur, right tibia, fibula, right metatarsus, pedal pha-
langes, several unguals, a nd an articulated distal tail section. The skel-
eton was examined for tooth m arks, but marks were only found on the
dentary.
The dentary is abo ut 1 2 cm long a nd very well preserved (fig. 6.1).
There ar e 1 5 oo th positions, with 1 0 eeth visible; five are fully erupted,
and three are partially erupted. Two other teeth (nos. 4 and 7 ) are
broken and show w ear facets, indicating tha t they were functional even
after they were broken. Three tooth marks were found on the lingual
surface of the d entary. Two of them bear serration m arks a s parallel
grooves or striae and have similar morphology. One of these tooth
mark s is located o n the bone and th e other is located on the crown of
the seventh tooth.
The first tooth mark consists of 6 or 7 parallel striae covering an
area 4 mm x 1.3 mm. Th e striae are positioned below the alveolus for
the third tooth, and just above the Meckelian groove. The striae are
orientated 45 from the long itudinal axis of the bone. Two of the striae
Tooth-M arked Small Theropod Bone 5 9
 
dentary
TMP88.121.39);
lingual
view, with three toot h ma rks.
are slightly turne d a t one end. Th e sizes of the striae are between 0.37
rn
and 0.40 mm, and they are cubo idal in cross-section.
The second tooth mark is below the fifth and sixth alveoli. It
consists of tw o smaller ma rks separated 1.8 an d 1.6 mm respectively
from a larger, central mark; all three are arranged in a straight line and
lack serration marks. The dorsalmost bite mark is 1.3 mm long and
resembles an inverted teardrop. Below this is a prominent V-shaped
groove with its axis approxim ately 60 from the longitudinal axis of the
bone. This mark is 6 mm long. It gradually expands from 0.2 m m to 1.3
mm, wh ere it cuts across the dorsal m argin of the M eckelian groove.).
W ithin the toot h mark the majority of bone fibers are broken; a few
fibers point ventrally, indicating the direction of tooth movement. The
ventralmost m ark is a circular impression 1.3 mm in diameter. These
three mark s probably formed a s the too th skipped across the bone.
Th e third to oth mark is located o n the lingual side of the seventh
tooth. This mark covers an area 2 mm mm, and contains four
promine nt parallel striae oriented a t right angles to the longitudinal
axis of the too th.
iscussion
Th e size an d shape of the serration in the tooth marks a re not like
those of Saurornitholestes, therefore excluding intraspecific face-biting
behavior (sensu Tanke an d Currie 199 5, in press) as a possible etiology
for the marks. The small theropod Dromaeosaurus has denticles that
are cuboidal in cross-section, as d o tyrannosaurids, but these denticles
would have produced finer serrations (Cu rrie et al. 19 90 ).The size and
cuboid shape of the tooth m arks on TM P88.121.39 are most consis-
60 A.
 
tent with those that could have been produced by a tyrannosaurid.
The ir small size indicates the biter was small, possibly a juvenile. B ut
whether these ma rks were produced by Gorgosaurus, D aspletosaurus,
or Aublysodon canno t be determined at this time. The placement an d
perpendicular orien tation of the striae in relation t o the upp er denti-
tion indicates that th e marks were no t produced by occluding teeth.
Th e similar serration morphology between tw o of the tooth ma rks
indicates th at they were m ade by a similar tooth. T he lack of serration
impressions in one of the t ooth marks m akes it difficult t o assign it t o
a specific theropod taxa. Nevertheless, the absence of other type of
serration pattern o n the specimen, makes it most probab le that i t was
also made by the same animal.
Preservational biases and methods of carcass consumption may
explain why tooth-m arked small theropod bones a re extremely rare.
The bones are small, and their thin, hollow construction is easily
destroyed. Furtherm ore, the small bones might have simply been swal-
lowed whole. Such factors makes the discovery of th e Saurornitholestes
skeleton all the more remarkable, especially on e with to oth marks.
onclusions
Based o n the morphology of the serrated toot h mark s found o n a
Saurornitholestes dentary, the trace maker may have been a juvenile
tyrannosau rid. This feeding trace is significant because it shows t ha t
tyrannosau rids did not feed exclusively o n herbivorous dinosaurs such
as ceratopsids and hadrosaurs), but also included carnivorous dino-
saur s in their diet.
Acknowledgments:
I am indebted to Dr. P. J. Currie for his man y
years of encourage ment a nd inspiration. Also,
I
H.
Tanke, an d P. R alrick for reviewing and editing the
manuscript. Suppo rt by staff of the Royal Tyrrell M useum Ca nad a)
and the Steno M useum De nm ark) is gratefully acknowledged.
References
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62 R.
(characterized
parsimonious
Formation of
ornithomimosaurs
(Se-
a
hypothetical
outgroup
morphological
divergences within Coelurosauria and
such as
Y3/"Y
ingroups,
as
Further-
the Upper Cretaceous
.
24 of these
(Srvofford
19991,
only
66
prove
"
[19
9
8l
limited
until such time as the more complete Mongolian specimens currently
referred to Alectrosaurus olseni
two
premaxillary
tooth
(from
the
presence
of
(Mader
and
Brad-
ley
(1.990)
lower, the
ontogenetic status of
dimorph.
Aublysodon molnari Paul 1988: The type of Awblysodon
mirandus is a set of isolated
premaxillary
teeth
from
the
Tudith
River
Aublysodon.
Formation
"the
Jordan
theropod"
(Molnar
1978).
Currie
(1987),
Paul
(1988)
and
new
genus,
is
positions
Mongolia, units of uncertain
Alectrosaurus
olseni
(Mader
an
aublysodontine,
at
present,
with
rable in
size to
Daspletosaurus.
The
process
is uncertain, and these features are
58
hood
(Carr
1999).In
the
present
a
possesses
an
inter-
the Ingeni Khoboor
(197
6) fails to correct for dorsolateral crushing of the braincase;
resto-
correct
short
rather
Maastrichtian
parsimonious
trees,
side other taxa.
relative
"Albertosaurzs"
that
were
ramus
of
lacrimal;
duced. However, in other trees Gorgosaurus is closer to the
Dasple-
support for this clade, and
given
Canyon Formation
Canyon
Formation
referred
by
Russell
(1,970)
taxon otherwise unknown from the Maastrichtian) may in fact be
a
juvenile
Albertosaurus.
of the anatomy
shared by Daspletosaurus and
than any other
The Phylogeny
a speci-
in other tyran-
forcefully
form,
form is
closer to
the
Dinosaur
Park
(Russell
1,970).
Two
in
in-
(the
Lsian
the
taxon
is
ongoing.
The
present
growth
series
of
the Nemegt Formation
North
American
Given the
of
the
in
press)
70
terial of
bataar
is
character-
within
Tyrannosauridae:
the
general
of
Gorgosaurus, G. lancensis.
represent
a
juvenile
surface,
maxillary
tooth
pending
more
those of the
in
tyrannosaurids,
however,
the
Thai
taxon
postcrania from
the Subashi
lic
the
phylogenetic
analysis
presented
here
addition
of
new
that
this
preliminary
analysis
a most successful hunter
and behavior of fossil reptiles in
general,
helped many
The
earliest
known
tyrannosaur
from
ca.
In
N.
Mateer
Short Papers,
of the Cretaceous. In K. Padian and
D.
J.
Chure
(eds.),The
Society.
Unwin
(eds.\,The
Age
of
Dinosaurs
Cambridge
Univer-
sity
Press.
Currie,
P.
J.,
sedimentology, and
(Upper
Cretaceous),
theropod ancestry
the Late
Cretaceous of
tion. Bulletin
358:
59-61.
Huene,
F.
1923.
34:
449-458.
with a description of the
skull of Stephanosaurus marginatus from
the same
Carpenter.
Mexico.
Journal
and bio-
J.
Natural History
and
revised
diagnosis
Microuenator
theropod dinosaur from
the Upper Cretaceous
of central Montana.
Kurzanov,
andZ.-M.
Dong.
1990.
J.
L.
Sanz
and
[The
259-265.
Paul,
G.
Simon
and
Schuster.
Sig6.
Annual
Reuiew
Swofford,
avian
5111-5116.
The
ordered, and
=
on supraoccipital
between 2.8 and 3.5;
1, poorly formed
no
digit.
(23)
than
(24)
ilium:
in
dorsal
view;
1,
present.
(29)
Supracetabular
crest
or less
pubis length
0,
absent
or
metatarsus dorsal
Maxillary
fenestra
cranial
tall or taller than long.
(44)
1, present;
13
or
fewer.
(46)
present.
(47)
rostral to lacrimals; 1,
slender; 1, inflated appearance.
1,
present.
(52)
rostral
to
(54)
Angle
bump;
lacrimal
and
postorbital
in
of
postor-
the same level as the squamosal-
quadratoiugal
contact.
78
panded laterally; 2, marn body rectangular, only small triangular
cranial
prong
latero-
less
relatively
margin rugose.
deep
(76)
nonel 1,
maxillary teeth
less than
of
centrum:
O
(86)
Distal
point;1,
blunt.
Aublysodon
molnai
(87)
small embayment.
(89)
amphiplatyan;1,
orbit; 1, contact below orbit in adults, orbit more
circular
(dorsoven-
tral
axis) than in other large
theropods.
Daspletosaurus
toro
sus
(97)
Premaxillary
view); 1,
to external nares.
maxillan-
tooth
three
times
h a
????? ????? ??l??
00000 00000 00000 00001
00000 0
00000 00000
00000 00000
Two Medicine tyrannosaurine: 53.1
1.
is
well
understood
(Abler
their
zero
degrees
(fig.
pegs
for
gripping
food,
gripped
a
pulling
(and
shaking)
its
head.
Evi-
dence
for
shaking
is
taken
the
finely
disrupted
uoid
("drill
hole")
compression in
the
disrupted as
to form
a void
would then
to the kerfing
to
fit
the
curves
the
front
standard
method
for
other
was
slot broke
shape as
Albertosaurus serrations,
'Washington,
D.C.:
Government
Printing
Office.
Farlow,
J.
J.
Tooth
Serrations
o
89
The
size,
structure,
and
roles
they
that are
feathers seen
in Archaeopteryx
function
(and
hence
a
possibilin'
functions
potentially
test-
structures surrounding its
in
hor-
izons
of
the
Jehol
Group
(Lower
featherlike
covering
(1998)
de-
scription
in
the
next
year
by
the
only
if
primitive,
feathers.
Protarchaeopteryx
and
metrical
vanes
and
parallel
barbs
plumulaceous
feathers
(Ji
skeletal
structures.
Since
been re-
toran coelurosaur, in a trichotomy with Velociraptorinae and all
ra-ra
genera
(Ji
to
former lineages. In any event the origin
of
birds
is
thus
and integumen-
to
NIGP 127587.
the
view,
are
disarticulated.
The ribs are splayed and flattened, as if they had been
pressed
obliquely
into
the
in
Flight
but
a
partial
clavicle
about
halfway
along
the
coid. It is less than 2
mm thick, so does
tetanurans
(allosaurids,
to
40
mm
some structures,
type
specimen
structured.
distributed, these
to be
the
the distal end
basal
theropods,
such
suggest that
on the
lateral rotation
distorted
the
carpals,
and
preserved.
Ji
et
al.
(1998)
mea-
quills
can
1 mm in diameter,
10
have suggested the
.
long,
of
which
half
the
area,
paratype
posterolaterally.
A
clavicu-
lar
fragment
and
2
as
distinctiy
two attached
to each
side of
men have
The
principal
differences
are,
first,
that
the
filaments
of
Sinosaur-
opteryx
central shaft around which
either
cam-
ouflaged
those
il:::"ffi
more
general
dis-
such
know
at
These
u'hvi
whether some selective
forelimbs
and
Recurring to Sinosauropteryx,
are so
long-ad-
vanced
have
been
claimed
for
either
juveniles
pair
of
false
purposes,
question
I
9
I
curved,
in
some
types
States
but
elevation.
Feathered
Dinosaurs
and
the
the
suggesting the riblike form
and
Caudipteryx
have
broad,
ovoid
sternal
plates
flartng at its
of the flight stroke
was
genera,
the
rudimentary
no
particular
adap-
tation
perform
teryx
not an
c
o
nou'
kttou,n
in
Compsognatbidae
fSinosauropteryx),
Th
erizino-
s
i dae
(
dromaeosaurs,
instead
other
structures
for
thermoregula-
tory
reasons
do
so
for
in the
oviraptorid
pre-
served
Jones,
and
J.
A.
Appleton.
perinatal
archosaurs:
Phylogenetic
and
Quarterly
Reuiew
of
Biology
49:2747.
Ostrom,
J.
H.
a bird
birds
J.
L.
Chiappe,
and
theropod
dinosaurs.
Nature
39221.L9-1.20.
134
saurs.
University
of
mass from
on-edge
the
set
is
than
character.
Most
R
of
elasmosaur
and
1994).They were
of the
Jurassic
(Cannon
1905;
Janensch
1929;
Grllette
(1,9871
lack
of
gastroliths
with
argues,
interior, and that the
Kenneth
Carpenter
m3.
The
pocket
they left impressions,
and about 30 to 50 cm anterior to the left femoral
condyle,
about 30 cm ventral to the vertebral column, and adjacent to
a
pubis
and
ilium
(fig.
gut
region
skeleton
(fig.
hillside. Taking
legs 2.5 m
well as some clast-to-
gastrolirhs.
Their
compact
of burial. Because the
Cedarosaurus ueiskopfae was collected in the Yellow Cat Mem-
ber of the Cedar Mountain Formation in eastern Utah. The Yellow Cat
unconformably
overlies
Formation
and
underlies
the
Poison
interi-
This
conclusion
is
sup-
ported
the clast-to-bone contacts that
dimen
sional
di
str
ib
ut
Rounded to Nearest
tends to
is
the
largest
gastrolith
0.48.
between 0.5 and
important if
smallest, directll'with
measured
Cedarosaurus
gastrolith
the
measured
for
Of the total
nificant, then the
physical
dimensions
(16.5
cm
largest
(715
gm,
(0.48
They
tend
None
of
the
gastroliths
have
contrary to the
suggestion by Stokes
the samples.
cluded more than one
2
fairly
well
had RVs
for
gastroliths.
using
Complete
polish
and con-
traction of
genus,
clast surfaces
gastroliths
in
previous
studies
(Man-
animal's
gut.
shape
and siltstone clasts
present,
the
hypothesis
that
cement.
In
also be consistent
of
ments,
for
Bond.
the
Forest
Sandstone
(upper
Karroo).
dinosaurs.
Burrows, C.
based on
'Wanaka,
IU 20
gastroliths.
J.
O.
Farlow
and
Antarctic Biota.
Geological Society
de Carvalho, D. Santos,
1998. Estudo
Jurissico
superior
por-
Mineiro,
1980.
Journal
gizzard
P
Carpenter, R. Cifelli,
biogeography. Geology Studies
surface
polish
pected
sauropod
gastroliths,
the
Late
er.rdence
o{
lumbian Museum of Natural History, Geological
Series 5
a Camarasau:ri
of
Shuler, E.
1950. A new elasmosaur from the Eagle Ford Shale of
Texas.
1
(part
(London),
B
34L:
control strategies
in aquatic
(eds.),
of South Dakota.
psittacosaur
(Psittacosaurus
Beijing:
volume, V, as the clast.
Formula
2:
as
Taz
ftc2
the
prolate
was computed as
no
closed-form
mathematical
solution
for
of the clasts that fall within the ellipsoid
region
of
figure
12.6
piece
of
I
i
and neonate-size
in
two
microfossil
sites
dominated
by
the acidic water
conditions of the
many thou-
sands of
or
skeletal
material
(especial-
ly
the
Numerous
from DPP are now known. Some specimens were derived from
extreme-
skeletal
oc-
More
recent
(Carpenter
only occa-
sionally been
is
specimen
partial
individuals
"no
larger
than
in
the
nestling-size hadrosaurs in
(1.987,1989),
de-
scribed
juvenile
hadrosaur
material
from
in
these samples occur
specimens
hadrosaurs
within
or
near
the
Park
these dinosaurs.
berta; NMC,
is
known
from
rofossil sites or bone beds
(BB),
act-
(Zele-
nitsky
pers.
comm.
19991.
Bones
entire,
such
as
factors, such as the small size of the specimens and
the
the carti-
of these bones
hadro-
(4
mm
thick)
(<0.5
mm
thick),
mm.
however,
feature not
a condition
seen in
is
a
heterochronic
head and the
are
The craniolateral
on the
and then
adult,
indicat-
in
ontogeny.
The
the compacta on the external surface
just
show
proportions
processes present,
but are
into
vegetation
(K.
Aulenback,,
pers.
show
bones
may
in DPP makes this scenario seem
doubtful. More likely, those bones
showing transport abrasion
from the
nearby
in DPP
within
BB
hadrosaur specimens annually
file in TMP
collections). Dinosaur eggshell
beds.
Perhaps
these
higher
stream transport.
of
bone
field
observation).
Conclusions
Hadrosaurs
ronments,
with other hadrosaur
hypothesis.
in
TMP collec-
tions staff.
Indi-
nesting
horizon
in
the
Judith
Devil's Coulee.
vertebrate
tana. Mosasawr 4: 127-142.
nesting
250
(4):
130-1.37.
bird colonial nesting
grounds. In K.
hadrosaurian
dino-
saurs.
Journal
A
comparative
Nature
332:
256-257.
Jepsen,
million
years
J.
hibernate as a
Journal
of
Paleontology
41
(1
Bulletin 136: t20-122.
Brett-Surman
Partial skull: 82.4.2
1955).
small
juvenile);
L-nJ:;::,:':::.;te,i
]:wnents:87.35.358
small
juvenile);
94.12.483
(proximal
half);
98.93.132
(complete?).
Undifferentiated
femur
fragments:
(bone
shaft).
Unnumbered
specimens
for
destructive
histological
SoecimenNumber Element
Length Prox.
can be attributed
to a single
sequences. This
cl. u elas co
suggest
Matanuska Formation as
area containing
a large
length. Some
large concretion, which
1 radius,
centra, 2 chevrons, and
narrow size
juvenile
ap-
proximatelv
3
meters
long.
F
of
fined
to
the
quarry
(Jones
1963).
The
density
The
preser-
and
this
The
(.,;,
n
t
f,,
with other soft
of life, which has
pit
are
inoceramids,
an
extinct
group
of
bivalves
nuculids,
and
protists
to resr
on its
highly indurated
characterizedby
surfaces
(depressed
frac-
planar
cross-section
they are U-shaped or conical and many have displaced cortical bone
fragments forming an
5.81
mm
in
metatarsal, two unguals
tibia
and
fibula.
led
proriger,
from
the
for
the
depressed
fractures
1.5
cm
from
wide at the base
dentar5 maxillary,
proriger
(fig.
of the
bathyal environment
damage
had
without. The bone-bearing
never
which they
primary
or-
ganisms
removed were modified by encrusters and borers. The bare
bones
provided
niches
and
hiding
places
smooth
that the TMH
(Hogler
1994).
the world. It has the
potential
partially
quarry
and
for
Ciuico di Storia
(Upper
Cretaceous).
Inner
Mongolia,
r27-r44.
Davis,
Geological
Inu
north
ornithopod from
central Honduras.
(ed.l,Tbe
Processes
of
Fossilization,
pp.270-292.
significance
(eds.),
1.999.The significance
.Wiley.
Thiede,
J.,
guished
largely
by
roof-in
particular,
nasal
number
of
Cenozoic
highly
derived
feeding
about the
the
possible
tortoises
is most
Socioecological
Correlates
Jarman
general
signals. Prolongation
of body
the reproductive
not
year
and
lasts
from
four
to
six
years,
with
rams
entering
to
groups
of
intrasexual
competi-
tion.
than
fernales.
Speculations
curs
monopolize
growth
of
cases
territorialitS
polygamy
and
territoriality,
predictability
in
social
relation-
ships.
Among
gregarious
of
rank
dant
in
be
perennial,
against
predation,
gener-
266
distinct
sexual dimorphism
to
Ceratopsid
Socioecology
Horns
and
Frills
as
Mating
Signals
How
do
evidence, but by far
horns
and
hornlike
bovids-in
Park, Alberta,
numerous
occurrences
gregarious
behav-
ior
species-specific
to be
Ceratopsidae,
is
the
and
digestion
of
poor-quality
fodder
(Farlow
1987).
'Sfith
regard
to
the
paleoflora
associated
with
Alberta,
are
encountered
more
to highlight
in
coossification
heteromorphg
complex social organization, as is said
to occur today among crocodii-
ians
or
"infestations"
akin
ove
putting
to
imply
that
shared
variable, both within
are a
forms
relatively nongregarious,
Predation Pressure
(Eisenberg
ly
it is likely that concealment was
typically
not
a
viable
strategy
regarded
as
by
the
formation
of
mixed-sex
(at
least
specific combat with the adorned skull used to catch or
parry
the attack
of an opponent. As expected on the basis of extant analogues,
sexual
in ceratopsids
and, where
presence
of
diverse
growth
in
some
support
the
notion
a means of
the
ous resource distribution. This
been a major
pursuing dino-
saur research, and he has been a stalwart supporter ever since.
I
sin-
-54.
Brinkman,
D.
B.,
M.
J.
Ryan,
and
herbivorous lizards.
American Naturalist
M. Friis,
Dinosaurs
death of a herd of ceratopsian
dinosaurs.
In
(eds.),Third
[Academy
of
Sci-
ences
Press].
Demment,
explanation
for
body-size
patterns
can Naturalist 125
An
ogy 101:1-118.
EcologS
197:215-223.
African
Bovidae.
In
Its Relation to
Euolution 29:
Mu-
reconstruction
UniversitS
Bozeman.
auiour
27
ecology in
of Ecology
Systematics 8: L93-207.
Geist, V. 1978. On weapons, combat and ecology. In L. Krames,
P. Pliner,
Journal
of
topsian dinosaur from Texas.
ceratopsian subfamily
Chasmosaurinae: Sexual
Pentaceratops
evolution of combat
65-
190.
systems in
Ostrom,
J.
birds
and
last
100
years
provincial
each
formation
within
blages
from
the
Late
s langstoni
o sauru
s al b e rte n
si s
Anchiceratops
ornatus
s breu
grac
genus
and
species;
Hs,
holotype
of
species;
ceous
paleontology,
of
Natural
Bulletin of the
History
33:
559-565.
Brown,
B.19L4c.
History
82:
121-149.
Carr,
vertebrate remains
248-261.
Cracraft,
J.
L971,.
Caenagnathiformes:
\fyoming.
from
the
38
49-64.
Gilmore,
C.
Sf.
1930.
77:1-39.
Horner,
J.
R.,
Stratigraphy,
Cretaceotrs Research
Alberta,
by
badlands of
Philadel-
phia
8:72-73.
Dinosaurs
species
Ornitho-
mimidae
and turtles
Russell,
D.
A.
1984.
A
checklist
National
Museums
of
Canada,
edmontonensis,
n.
118:709-120.
Sternberg,
C.
from the Upper Edmonton member on the Red Deer River,
Alberta. Bulletin of the National Museum
of
Canada
of
the
Cretaceous
of
Alberta.
Journal
of
Paleontology
14:
81-85.
small
theropod
 
saurus Matthew
aur u
s Lamb
s
is
C.
M.
Sternberg'1,932,
Dinosaurs
17
Edmontosaurus
nberg
1
950
to be validated.
a single tooth.
outcrop; the
(BMNH
(\1R-#:*r
Elmisauridae
the
Horseshoe
the Saurornitbolestes
sp. teeth
abrasion, and, additionall,v,
reexamined
truly
presenr
in
appear to be caused by growth
anomalies
in
teeth
from
other
taxa
(Currie
dence of unusual
exhibit distinct,
been
reported.
Recent
discoveries
of
additional
identifiable
specimens
have
al-
preserved
paleosols,
the
formation
and
rapidly
that comprise the
the
Blackfeet
Two
primarily
conducted
in
these
three
gulation
and
led
by
John
Horner
(1984,
1992;
Horner
and
t
299
a
Institutional
Abbreuiations.'
seum of the
cine Formation
and also
Museum crew under Charles Gilmore collaborated in recovering the
first
more
with
In
addition
to
Gil-
report
any significant discoveries,
and research by both Brown and Gilmore was halted by'World War
II.
the following
short
be the
Maiasawra
peeblesorum
by
discoveries became the basis for
a
re-
panian
Stage.
Rogers
(10.1
receding
and
the Eagle Formation.
and upper
been
interpreted
formation
suggest that a more upland environment existed in the south during
deposition of the basal
after deposition of
found
directly
un-
derlying
the
Judith
Formation
(Lorenz
and
Gavin
1984).
the area were inundated
of
Alberta
(Stebinger
1914;
plain
far
is
distinguished
from
Medicine deposition
sediments overlie
Formation
be-
long
to
the
Maiasaura unguals have been reported in the Dinosaur Park For-
mation
of
southern
Alberta
(Currie,
pers.
comm.)
and
the
Claggett
recently,
un-
prepared
by
Hypacrosaurws stebingeri
peeble-
sorum
(ROM
collected
in section than the OTM
specimen.
r
Hypacrosaurus
sp.
(MOR
col-
lections).
The
the middle
one
of
the
primary
(cf.
Daspletosaurzzs,
portions
of
the
formation.
it
is
possible,
unlikel.v',
the
inaccurafe inference
result
of
as
major
in
and
of
the
the area
in
section
in
lackfe
ete
nsis
Edmontonia
rugosidens
of the
the range of sediments
been
the apparent diver-
ornithischians, including
tion
rather
than
preservational
bias.
A
major
problem
with
interpreting
the
themselves.
rain shadow
the west.
Medicine
Formation
is
presently
our understanding is
Car-
penter,
stratigraphic, and
Judith
occurrence of
North Central
Montana. Master's
ceratopsian
dinosaur
from
the
'livo
Gilmore,
C.
\)f.
1930.
of the United
Horner,
J.
with discussion of evolutionary
Nest of
Horner,
J.
gressions
and
358: 59-
Formation
gronnd.
Mon-
Sun
River
Rogers, R.
bone beds
Formation
(Upper
Cre-
taceous),
northwestern
Montana,
horned dinosaurs
from the
Upper Cre-
thesis, Department
of Biological
G.
of
Petro-
provincial.
Distinctive
en-
Campanian
time,
diverse
and
highly
specialized
hadrosaur-dominated
faunas
arose.
However,
in
Maastrichtian
and the reduc-
tion in kinds
geographic
changes
pri-
of dino-
sampled
intervals.
stands
in
marked
modern large
North American
of these species
to dinosaurs.
differed
ecologically
and
plains
particularly
the
been
areas
it
is
possible
material
the
present
review
fo-
cuses
on
the
distribution
of
large
herbivorous
dinosaurs.
Their
restric-
the strati-
records not
only those evolutionary changes that occurred over time, but also the
progression
existed
from
coastai
habitats
at
low
progressively
ascending
a
mountain
range
resemble
paleo-
are thought
to oversimplify
more complex
biotic variation.
Instead, large
interior
(Normapolles)
wet
shrubland
biome.
in both northern
At
the
same
in North
many
as
ten
genera
of
bi,t:otte.
:d,tpted
from
r
1991 .
,\lltrt
itl
plain-coastal
p
(5)
(9)
-
andEdmontosaurus,llkely
ancestors
to
Lancian
dominants
Triceratops
(late
with
aspect.
consUu cti on
of the western
interior region of
replesentattt es ol the
end
of
also
generally
thought
to
record
in South America
an immigrant
from South
that Alamosaurus
was an
of
upland
regions
tend
graduai
replacement.
lineages
of sauropods,
elevations
the
(e.g.,
Harrison
Lancian
decades
Cretaceous
a
ring
a diverse
bovids
herbivore
groups
(elephants,
rhinoceros,
deglaciation
perhaps
pro-
duced effects similar in some ways to those resulting from the
culminat-
(bovids
been
inhibited
zones expanded
here were
York:
L. D. Carter, and
Slope,
Alaska:
High
lati-
Burt,'W.
H.,
and
D.
Dyman, T.
USA,
pp.
365-392.
Denver:
Rocky
Mountain
for
Sedimentary
Geology.
Forster,
C. A., P. C. Sereno, T. W. Evans, and T. Rowe. 1993, A
complete
skull
(Dinosauria:
Ceratopsidae)
from
the
Aguja
Formation
(Late
Campanian)
of
'West
Texas.
Journal
of
Vertebrate
P
Horner,
J.
with discussion
of evolutionary
pp.
(Reptilia,
Horner,
J.
logical
Society.
Horner,
I.R.
1992.
Cranial
dinosaurs.
Nature
358:
59-
bl.
co. In S.
tin 2.
J.
Eaton,
to
un-
local fauna: A new look at the old
326
gy,
Late
Cretaceous
(earliest
Campanian/Maastrichtian)
evolution
of
to known
D. Rose
lateral variations in the composition
of
Late
Aguja Formation,
of
the
dinosaurs:
A
Late
Cretaceous
with
a
phylogenetic
analysis
of
the
Centrosaurinae
(Ornithischia:
Ceratopsida
e).
J
ournal
Oklahoma
in
(eds.l,
Memoir 5: 1-68.
mechanical strength
of
great
interest,
especially
with
respect
to
question
of
predation
changes
activity
(Rothschild
activi-
the
lesions
were
limited
to
the
pes,
lated
fractures
nized on the basis of diaphyseai surface bulges, usually, but
not invari-
::iI :,ili
clear
zone
west Museum
(table
manus and
Velocisawrus
12
Mononykus
15
Megalosaurus
16
Allosaurus
1.71281
Marshosaurus
5
Ornitholestes
20
Compsognathus
9
Alectrosaurus
23
Albertosaurus
11319
Tyrannosaurus
1181
manual lesions.
affected
families
precludes
of that
hu-
meri.
volume). Scapular distribution
to the distal
lateral surface, where
margin
"the
lower
for
Gordon
Bell,
Chure,
Stephen
Czerkas,
Rebecca Hanna,
Stadtman,
J.
D.
Stewart,
Mary
Thanks
to
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10600)
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"a
variety
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gently
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Albertosaurus
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(1)
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are
incom-
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patholo-
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Allosaurus
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Allosaurus
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Tyrannosaurus rex
/
/.
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\Webb
may
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thar
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Jack
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John
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Abiquiu,
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the
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the
valley
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