RE: Podokesauridae, Problems of Nomenclature Returned

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

Jaime Headden wrote:

>  I like the idea of the podokesaur/coelophyse implosion. However, as
>for *Podokesaurus* itself, I was to understand that it was indeterminate
>whether the material could be differentiated ontogenetically. The late
>Ned Colbert and Dale Russell had doubts as to the specimen's age, as >well
as the nearly complete lack of apomorphies. 

I think coelophysid/podokesaurid taxonomy is already in the midst of a "Big
Crunch".  _Podokesaurus_, _Eucoelophysis_ and _Camposaurus_ are already
being lumped into _Coelophysis_ by some workers - not as separate species
from _C. bauri_ (as George suggested), but as indeterminate _Coelophysis_
specimens (_Coelophysis_ sp.).  Some of the apomorphies that were used to
diagnose _Podokesaurus_, _Eucoelophysis_ and _Camposaurus_ appear to be
absorbed by the range of morphological variation seen in Ghost Ranch _C.
bauri_.

On the other hand, _Syntarsus_, if sunk into _Coelophysis_, would remain as
two separate species - _C. rhodesiensis_ and _C. kayentakatae.


> Nonetheless, nothing indicates that
>*Podokesaurus* is _not_ closer to *Coelophysis* than any other group of
>theropod, and this still means bad news for "Coelophysidae."

This is another example of where "good" families suffer because they are
named after "bad" genera.  Under current ICZN rules, if _Podokesaurus_ is a
junior synonym of _Coelophysis_, the family must keep the name
Podokesauridae.  In an analogous example, the family that includes
_Chirostenotes_ and _Caenagnathus_ will continue to be called Caenagnathidae
even if _Caenagnathus_ is shown to be a junior synonynm of _Chirostenotes_.

If, however, _Podokesaurus_ is a _nomen dubium_, then it is disqualified
from being the nominative genus for family-level taxa - therefore
Coelophysidae wins over Podokesauridae.  For the same reason,
Tyrannosauridae rather than Deinodontidae is the valid name for this clade,
even though Deinodontidae was named first; _Deinodon_ is an invalid name.

Confused?  I am - and hopefully the rules will be changed so that families
do not have to be anchored to genera of dubious validity, simply because of
the chronological order in which these families were named.  



Tim