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Titanosaurid neuroanatomy



From: Ben Creisler
bcreisler@gmail.com


A new online paper:

Ariana Paulina Carabajal (2012)
Neuroanatomy of Titanosaurid Dinosaurs From the Upper Cretaceous of
Patagonia, With Comments on Endocranial Variability Within Sauropoda.
The Anatomical Record (advance online publication)
DOI: 10.1002/ar.22572
http://onlinelibrary.wiley.com/doi/10.1002/ar.22572/abstract

The purpose of this study is to provide a detailed description of the
neuroanatomy of Bonatitan, Antarctosaurus, and an unnamed titanosaur
from Río Negro, Argentina including the first observations on the
inner ear of the two first taxa using CT scans. The materials were
compared with previously described sauropod endocasts and other less
complete titanosaur braincases from Argentina. The cranial endocasts
show the general morphology of other sauropods being bulbous,
anteroposteriorly short and transversely wide, and with enlarged and
posteroventrally projected pituitary body. Particular titanosaur
traits are the extremely short and horizontal olfactory tract, the
absence of a floccular process and a single root for cranial nerve
XII. In addition, in the basicranium the abducens nerve (CN VI) does
not penetrates the pituitary fossa and the internal carotid artery
enters the medial aspect of the basipterygoid process, resulting in an
external opening for this vessel that is not visible in lateral view
of the braincase. The titanosaurid inner ear also exhibits particular
traits, such as robust semicircular canals, and anterior and posterior
semicircular canals that are subequal in size. The variation observed
in the sauropod endocranium indicates an evolutionary tendency in
titanosaurs toward the anteroposterior shortening of the midbrain, and
the reduction in size of the semicircular canals of the inner ear, in
particular the anterior semicircular canal. This, together with the
lack of floccular process suggests a narrower range of movements of
the head for this clade.