RE: Rauhut's Thesis

[rbi <rbi@dana.ucc.nau.edu>]

>>then I would have a hard time beleiving that the crest is convergent.<
>Why not? Ceratosaurs apparently like to "play around" with cranial
>ornamentation (_Dilophosaurus_, _Ceratosaurus_, "Syntarsus" _kayentakatae_).
>I see no reason to place two ceratosaurs in the same genus based on the
>presence of cranial ornamentation.

Just because two genuses have very similar cranial ornamentation doesn't mean
that the ornamentation is convergent.  They could have a common ancestor with
a dual crest, and therefore, the item is homologous.  Also, let us thing of
genetics.  There is a particular gene that codes for a crest.  It is on in a
species 1.  It gets turned off when 1 evolves species 2.  It then gets turned
on again when species 2 evolves species 3.  Osteologically, this could be a
convergent crest.  Genetically, however, it is a completely homologous feature
shared by species 1 and 3.

>So, clear conclusion:
>"Dilophosaurus" _sinensis_ is (IMNSHO) a ceratosaur, possibly a
>coelophysoid, but not congeneric with _Dilophosaurus_.

Yes, yes it is.

Regards,
Randall Irmis