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Massospondylids




On Mon, 18 Jun 2001 Dinogeorge@aol.com wrote:

> In a message dated 6/18/01 2:06:50 AM EST, Adam.Yates@bristol.ac.uk writes:
> 
> caudofemoralis had been torn off at some point in its life).  >>
> 
> I got the impression that Cooper had more than this, but unfortunately my 
> copy of his big paper is buried and I can't check it. If this is true, then 

Cooper illustrates three femora in his paper, QG 1159, 46 and 1161. Only
1159 displays the pendent condition. He states that QG 1159 may display
a mutative characteristic that is of phylogenetic significance but is
vague on the point of wether it is a single specimen or if there are
others. Of the five femora I looked at while at the BPI none had the
pendent 4th trochanter.  

> On another track, I think Massospondylidae right now includes only 
> Massospondylus. Lufengosaurus and Coloradisaurus are good plateosaurids, not 
> massospondylids; and Yunnanosaurus and Jingshanosaurus are good 
> yunnanosaurids. So if they didn't have pendant 4th trochanters, it's not 
> particularly relevant. I wouldn't consider ornithischians and plateosaurids 
> or yunnanosaurids particularly closely related.
> 

Well that's one possible classification, but I don't think it accurately
reflects prosauropod relationships. There are some big differences
between Plateosaurus and the others. For instance Plateosaurus has 25
presacrals and a caudosacral in the sacrum whereas Massospondylus and
Lufengosaurus have 24 and a dorsosacral. There are also some thumb and
skull characters linking Massospondylus, Yunnanosaurus, Jingshanosaurus
and Coloradisaurus to the exclusion of Plateosaurus. I can't find any
characters that unite Lufengo with Plateo to the exclusion of Masso
(Sereno used two but these don't stand up to scrutiny). Coloradisaurus
shares some characters with Plateosaurus but an equal amount with
Massospondylus as well. Like I said earlier I can't wait to synthesize
all my new observations but I have a whole heap of distractions in my
way at the moment.

cheers

Adam Yates