RE: Genyodectes?

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Nick Gardner wrote:

> Apparently, HP G.S. Paul (1988) very, very tentatively suggests that 
> Genyodectes serus is synonymous with Abelisaurus comahuensis (pp. 283).
> G. was named in 1901 whereas A. was named in 1985.  If this is the case,
> then won't G. have priority?  

Not necessarily.  The _Genyodectes_ material (the rostral portions of upper
and lower jaws, if memory serves) may not be diagnostic at the genus level.
If overlapping material does reveal that the _Genyodectes_ jaw material is
identical to the rostral portion of _Abelisaurus_'s skull, then the name
_Genyodectes_ does not necessarily have priority.  One must prove that the
_Genyodectes_ type material is sufficient to be a name-bearing type
specimen.

This situation would probably be analogous to the taxonomy of
_Majungasaurus_ and _Majungatholus_.  The former was named first, but is
based on scrappy material that is not diagnostic at the genus level.  The
_Majungasaurus_ type material is indistinguishable from that of specimens
referred to _Majungatholus_; but Cathy Forster, Scott Sampson and others
chose _Majungatholus_ as the valid name of the horned Malagasy abelisaur
because the name is attached to diagnostic material.

> Paul states that the material can no longer serve as a valid type 
> because the type locality cannot be determined.  

I'm not certain that lack of provenance data disqualifies a genus or species
from being regarded as valid.  Quite a few dinosaur species were named from
type material collected at an unrecorded locality.

> Could someone clear up what would be done with Abelisaurinae, 
> Abelisauridae, Abelisauroidea, Abelisauria, etc. if Paul is indeed 
> correct?  

That's a big *if*.  But nothing would happen to Abelisaurinae,
Abelisauridae, Abelisauroidea, Abelisauria.  If _Sinraptor_ is a junior
synonym of _Yangchuanosaurus_ (as argued recently), then the family
Sinraptoridae is still valid if it includes _Yangchuanosaurus_.  Similarly,
the family that includes_Chirostenotes_ can still be called Caenagnathidae,
even if _Caenagnathus_ is a junior synonym of _Chirostenotes_.

My 2c.



Tim