Ceratosaurus endocranium, ornithischian brain size

[Michael Mortimer <mickey_mortimer111@msn.com>]

Two new Mesozoic dinosaur papers in the new Acta Paleontologica Polonica.

Sanders, R.K. and Smith, D.K. 2005. The endocranium of the theropod dinosaur 
Ceratosaurus studied with computed tomography. Acta Palaeontologica Polonica 
50 (3): 601?616.
http://app.pan.pl/acta50/app50-601.pdf

Very interesting.  Though they call Ceratosaurus a tetanurine (ha!), the 
braincase description is quite extensive.  They find both Ceratosaurus and 
Alioramus have pneumatic frontals, which means the character's more common 
than previously thought.  The authors also found ridges indicating caudal 
olfactory conchae, as have been previously reported in Nanotyrannus.  Oddly, 
Ceratosaurus also has hollow paroccipital processes, which are supposed to 
be restricted to coelurosaurs.

Evans, D.C. 2005. New evidence on brain−endocranial cavity 
relationships in ornithischian dinosaurs. Acta Palaeontologica Polonica 50 
(3): 617?622.
http://app.pan.pl/acta50/app50-617.pdf

Apparently hadrosaurids and pachycephalosaurids have vascular imprints on 
their endrocranial surfaces, showing that their brains filled their skulls, 
much as in maniraptoriformes.  Thus, their EQ is higher than previously 
believed.

Mickey Mortimer