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Re: Nyasasaurus Update




On Wed, 22 Aug 2001 Dinogeorge@aol.com wrote:

> In a message dated 8/21/01 2:26:57 PM EST, amaris@tin.it writes:
> 
> << And what about "Gyposaurus" sinensis?
>    What is the current phylogenetic interpretation of this taxon?
>    I've seen rumor that it's the same as Massospondylus. >>
> 
> It's currently Anchisaurus sinensis, since Gyposaurus was synonymized with 
> Massospondylus by Cooper in his African prosauropod implosion paper
> 
> Cooper, M. R., 1981. "The Prosauropod Dinosaur Massospondylus carinatus Owen 
> from Zimbabwe: Its Biology, Mode of Life and Phylogenetic Significance," 
> Occasional Papers of the National Museums and Monuments, Rhodesia 6(10): 
> 689â??840.
> 
> Ultimately Anchisaurus sinensis may be synonymized as a juvenile of some 
> other Chinese prosauropod or may be made the type species of a new genus. I 
> don't think there's much evidence that Anchisaurus occurred in both China and 
> North America during the Early Jurassic.

"Gyposaurus" sinensis shares no characters with Anchisaurus that are not
found in all, or most, other "prosauropods" (well at least none that I'm
aware of). The only reason the species appears as a basal prosauropod in
Sereno's (1999) cladogram is that it has short blocky cervical vertebrae
(see Galton's reconstruction in Galton and Cluver). However I have some
evidence that suggests that neck elongation in prosauropods happened
quite late in "prosauropod" ontogeny (e.g look at the very short
cervicals of Mussaurus). Also the "G." sinsensis material does share a
lot of derived similarities (possibly even some atapomorphies) with
Lufengosaurus huenei (which is from the same formation as "Gyposaurus"
sinensis). I therefore see no reason to regard "G." sinesis as anything
but juvenile material of Lufengosaurus huenei. 

cheers

Adam Yates