RE: Rauhut's Thesis

["Tim Williams" <twilliams_alpha@hotmail.com>]

Randall Irmis wrote:

> Don't you think it is odd that three ceratosaurs outside of the
> Neoceratosaurs
> have a double crest formed by the same bones and has the same form?  I
> can't
> see this as just convergent.  [snip] In S. kayentakatae, D. wetherilli, and
> D. sinensis, the crest is exactly the same in how it develops from the
> cranial
> bones. So, I think it is not convergent.



The double-crest of _Syntarsus kayentakatae_ was restored with
_Dilophosaurus_ very much in mind.  AFAIK, no _S. kayentakatae_ specimen
exhibits this type of crest in its entirety; the presence of a dual
nasolacrimal crest in _S. kayentakatae_ was inferred from the structure of
the (incompletely preserved) skull roof in the type specimen.

According to Colbert (1995), _Coelophysis_ specimens from Ghost Ranch may
show an incipient double-crest in the sharp angle at which the lacrimal
connects the skull roof.


Tim


------------------------------------------------------------

Timothy J. Williams

USDA/ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163

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