Re: Antentonitirus pro-nun-see-a-shun?

["Tim Williams" <twilliams_alpha@hotmail.com>]

Mickey Mortimer wrote:

> First, as Holtz said, Blikanosaurus and Melanorosaurus are equally old.
> Isn't Euskelosaurus too, indeterminate or not?

There may be other Late Triassic sauropods besides these.  The Isalo 
Formation of Madagascar has yielded at least two sauropod taxa: 
_Lapparentosaurus madagascariensis_, and an unnamed _Bothriospondylus_ 
species.  The Isalo Formation was previously estimated to be of Middle 
Jurassic (Bathonian) age, but Flynn et al. (1999) imply that the entire 
Isalo Group may be of Triassic age.  Prosauropod material was recovered from 
the older "Isalo II", and given as Middle Triassic age.

> Not that I'm against using this definition of Sauropoda, but people have to 
> realize it's more of a change in taxonomy than knowledge that's giving us 
> so many early/basal sauropods.

A good point.  _Blikanasaurus_, _Melanorosaurus_ and _Anchisaurus_ have not 
suddenly become more "sauropod-like".  As Mickey said, what's happened is 
that the name "Sauropoda" has slid further down the sauropodomorph tree, 
pulled there by the reorganization of basal sauropodomorphs.  By dint of its 
stem-based definition, the composition of Sauropoda is at the mercy of 
_Plateosaurus_ and its relative position in sauropodomorph phylogeny.




Tim


References

Flynn, J.J. et al. (1999).  A Triassic fauna from Madagascar, including 
early dinosaurs.  Science 286 (5440): 763-765.

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