Re: Sereno's Prosauropoda

[TWILLIAMS@canr1.cag.uconn.edu]

>well as individiually coded "prosauropod" and primitive sauropod taxa).  I
>would not be terribly surprised, for example, in seeing _Thecodontosaurus_
>as the sister taxon to all other sauropodomorphs,

Yeah, I wondered about that too.  Based on Galton's summary of the genus 
(Galton, 1990 in _The Dinosauria_), _Thecodontosaurus_ is short-necked 
(compared to other prosauropods), quite lightly built, very small in size 
(~2.5m), and was probably fully bipedal (forelimbs and hands are poorly 
adapted for supporting the weight of the body).  

A strong tendency towards quadrupedality (and more robust skeletal elements) 
could be primitive for a clade uniting non-thecodontosaurid prosauropods 
with sauropods.  The anchisaurids may lie outside this clade too (although 
Sereno interprets _Anchisaurus_ as more derived than _Riojasaurus_).

A detailed comparison between _Thecodontosaurus_ and (say) _Herrerasaurus_ 
might be useful for this kind of analysis

On a totally separate issue, I noticed in Sereno's Evolution paper that the 
range of the Heterodontosauridae is given as extending to the end of the 
Jurassic.  Is this news to anyone else?  I wasn't aware of any 
heterodontosaurid material from the Late Jurassic.


Tim