Livro de Resumos - Dinossauros do Maranhão

Paleontologia 209
New record of theropod teeth assigned to Unenlagiinae (Dromaeosauridae)
at Barreales Lake, Neuquén, Argentina
1 Universidad Nacional del Comahue, Centro Paleontológico Lago Barreales- Proyecto Dino, Ruta Provincial, 51,
Km 65, Añelo, Neuquén, Argentina.
Juan D. Porfiri 1 , A. Flávia A. Coelho 1 , Jorge O. Calvo 1 & Domenica Santos 1
At the Futalognko site, Upper Cretaceous of the Portezuelo Formation, on the North Coast
of Barreales Lake, Neuquén, Argentina, hundreds of fossil vertebrate remains have been
rescued. Since 2001 several dinosaur taxa were described, such as the species
Futalognkosaurus dukei and Unenlagia paynemili and also new materials of Megaraptor
namunhuaiquii. Associated to these fossils, numerous remains of bivalves, angiosperms,
eggshell fragments, turtles, crocodiles, pterosaurs, ornithopods, and hundreds of
sauropods and theropod teeth were collected. Among the latter, several morphotypes
have been recognized, many of them without specific assignment. However, new studies
of a particular group of teeth with conical morphology have allowed to identify two new
morphotypes. The first one (MUCPV 671, MUCPV 1153) is characterized by the presence of
a labial carinae. The second one (MUCPV 1049, MUCPV 1134) possesses two carinae,
placed on the lingual and labial sides. Both morphotypes are characterized by having a
suboval section, being laterally uncompressed, and lacking wrinkles and denticles on the
carinae. Recent discoveries of unenlagiines dromaeosaurids, such as Buitreraptor
gonzalezorum and Austroraptor cabazai, preserve cranial and dental materials which
provided a more accurate idea of the dentition of this group. The unenlagiines include
other fragmentary taxa such as Unenlagia comahuensis, U. paynemili and Neuquenraptor
argentinus. The characteristics of teeth of Buitreraptor are: significant lateral compression
of the crown, eight-shaped basal section and unconstricted root-crown transitions, while
the Austroraptor characteristics are: conical-shaped teeth, caudolingually hooked. Both
taxa present ridges and grooves on the lateral side of the crown and a total absence of
carinae. Since the general morphology of the new morphotypes here presented coincides
with those present in Buitreraptor and Austroraptor, it is probable that these teeth from
the Futalognko site correspond to an Unenlagiinae dinosaur. Keeping in mind that
Unenlagia paynemili was found at this site, these teeth might belong to this species, and
the characteristic of possessing carinae could be considered as a distinguishing
characteristic for this species. Funding: Proyecto Dino, Universidad Nacional del Comahue,
Pan American Energy.
E-mail: domenicadsantos@yahoo.com.br
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