Procoelous caudals (was Re: PROG. PALAEO. '98)

[twilliams@canr1.cag.uconn.edu]

> Since everyone seems to believe that _Opisthocoelicaudia_ is a titanosaur,
> there's no reason to exclude platycoelous/amphicoelous caudals from
> Titanosaur[ia; formes; oidea; idae; take your pick]. These could simply be
> transitional between the familiar procoelous caudals of most
> titanosaurs and the opisthocoelous caudals of _O._

This character has always confused me.  A great many sauropods which 
are certainly not (as far as I am aware) members of the Titanosauria 
also have procoelous caudals - such as _Mamenchisaurus_ (strongly 
procoelous proximal caudals), _Diplodocus_, _Dicraeosaurus_, _Amygdalodon_, 
_Pleurocoelus_/_Astrodon_, _Cetiosauriscus_ (mildly so), etc.

Is there a possibility that this character is primitive for the 
Eusauropoda (i.e. all sauropods except _Vulcanodon_ and the other 
basal taxa)?



> 
> Dripping with sarcasm...
>