INVESTIGADORES
PAULINA CARABAJAL ariana
congresos y reuniones científicas
Título:
A New information on the braincase Sinraptor dongi (Theropoda: Allosauroidea): ethmoidal region, endocranial anatomy and pneumaticity
Autor/es:
PAULINA CARABAJAL, ARIANA; CURRIE, P. J.
Lugar:
La Plata
Reunión:
Congreso; X Congreso Argentino de Paleontología y Bioestratigrafía. Resúmenes; 2010
Institución organizadora:
Universidad Nacional de La Plata
Resumen:
The ossified
ethmoidal elements of Sinraptor (IVPP
10600) are U-shaped, and the frontal roofs the olfactory tract and cavities.
When the ethmoidal ossification is placed in anatomical position in the
braincase, an unossified space remains between the sphenethmoid and the
orbitosphenoid. This suggests there was a cartilaginous septosphenoid when the
animal was alive. The braincase was CT scanned after removing the sediment
filling the endocranium and pneumatic recesses, and this led to the recognition
of some traits that have not been previously described. Particularly
interesting is the presence of a well developed caudal tympanic recess
(generally considered as a trait characteristic of coelurosaurs), and the
internal morphology of the basisphenoidal recess and associated pneumatic
cavities. There is a longitudinal passage connecting the lateral tympanic
recess with the basisphenoid recess that probably had both pneumatic and
vascular functions. Endocranially, there is no medullar eminence, and the
floccular recess has an hour-glass shape. The volume of the endocranial cavity,
excluding the olfactory tract and bulbs, is 95 ml. The cephalic and pontine
flexures are similar to those in carcharodontosaurids (Carcharodontosaurus and Giganotosaurus),
although the disposition of cranial nerves II-IV in the midbrain varies amongst
these taxa. The CT scans revealed a small second branch for cranial nerve XII.
The encephalization quotient calculated for Sinraptor
is within the range calculated for other carnosaurs. The comparison within
Allosauroidea indicates that the endocast of Sinraptor shares more similarities with carcharodontosaurines and Allosaurus than with Acrocanthosaurus, which has an endocast
that is strongly different from other carcharodontosaurids.