New Conchoraptor paper # 2...

[Guy Leahy <xrciseguy@sbcglobal.net>]

Another article from the same issue of
Naturwissenchaften:
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Naturwissenschaften 
Publisher Springer Berlin / Heidelberg 
ISSN 0028-1042 (Print) 1432-1904 (Online) 
Issue Volume 94, Number 6 / June, 2007 
Category Short Communication 
DOI 10.1007/s00114-007-0219-1 
Pages 499-504 

Short Communication
Avian-like attributes of a virtual brain model of the
oviraptorid theropod Conchoraptor gracilis 
Martin Kundrát1 

(1)  Department of Biological Sciences, Macquarie
University, Sydney, New South Wales, 2109, Australia 

Received: 9 June 2006  Revised: 11 December 2006 
Accepted: 18 December 2006  Published online: 3
February 2007 

Communicated by G. Mayr
Abstract  An almost complete adult endoneurocranium of
Conchoraptor gracilis Barsbold 1986 (Oviraptoridae;
ZPAL MgD-I/95), discovered at the Hermiin Tsav
locality (the Upper Cretaceous) in Mongolia, is
analyzed. A virtual model of the endoneurocranial
cavity was derived from CT scans and represents the
most complete maniraptoran endocast to date. It
displays reduced olfactory bulbs, large cerebral
hemispheres in contact with the expanded cerebellum,
an epiphysial projection, optic lobes displaced
latero-ventrally, presumptive cerebellar folia,
enlarged cerebellar auricles, and a deep medulla
oblongata with a prominent ventral flexure. Contrary
to Archaeopteryx, the shortened olfactory tract and
cerebellum overtopping cerebral hemispheres of
Conchoraptor resemble conditions in modern birds.
Calculating brain mass relative to body mass indicates
that Conchoraptor falls within the range of extant
birds, whereas Archaeopteryx occupies a marginal
position. Most of the endoneurocranial attributes,
however, have a less birdlike appearance in
Conchoraptor than do corresponding structures in
Archaeopteryx and modern birds in which 1)
postero-laterally expanded hemispheral domains broadly
overlap the optic lobes, 2) the epiphysis projects to
the posterior cerebrum, 3) lateral extension of the
optic lobes substantially decreases a brain
length-to-width ratio, 4) optic lobe and anterior
hindbrain are superposed in lateral view, and 5)
cerebellar and midbrain compartments are in distinct
superposition. The endoneurocranial characteristics of
Conchoraptor, taken together, suggest that the animal
had a keen sense of vision, balance, and coordination.
The data presented in this study do not allow an
unambiguous assessment whether the avian-like
endoneurocranial characteristics of the flightless
Conchoraptor evolved convergently to those of avian
theropods, or indicate a derivation of oviraptorosaurs
from volant ancestors. 
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Guy Leahy