Re: Tyrannosaurus imperialis?

[twilliams@canr1.cag.uconn.edu]

> This brings up another question I've been meaning to ask. _Deinodon_ was
> named half a century before _Tyrannosaurus_, and it was given its own
> family. Thus, technically shouldn't the taxa Tyrannosauroidea,
> Tyrannosauridae, etc. be called Deinodontoidea, Deinodontidae, etc.?
> _Deinodon_ may be dubious, but no one disputes that it belongs in the same
> family as _Tyrannosaurus_.

No one disputes that _Deinodon_ is a tyrannosaurid, but it's still an 
invalid genus because it is based on indeterminate material.  As a _nomen 
dubium_, _Deinodon_ cannot be the nominative genus for any subfamily, 
family, or superfamily.  ICZN rules.

> There are other cases where families are named
> after invalid/dubious genera: Ceratopsidae, Caenagnathidae, etc.

You may soon be adding Hadrosauridae, Titanosauridae, and perhaps 
Troodontidae to the list of families named after invalid genera 
(which would therefore makes the families invalid).

_Ceratops montanus_ may prove to be a valid species if (?topotypic) 
material from the vicinity of Milk River turns out to be diagnostic.  
I'm not sure if this new material is topotypic - does anyone out 
there know?

Caenagnathidae remains valid; the fact that _Caenagnathus_ was sunk as a 
junior synonym of _Chirostenotes_ (was it by Hans-Dieter Sues?) doesn't
change a thing.  _Caenagnathus_ is still in the family (as a 
subjective junior synonym of _Chirostenotes), and it is not a nomen 
dubium.  Caenagnathidae stays.