RE: Brachytrachelopan mesai [was Short-necked dinosaur challenges accepted theory]

[Tim Williams <twilliams_alpha@hotmail.com>]

Jaime A. Headden wrote:

>   My initial comment on the animal is that it's not as "upsetting" of any
> theory as it might be touted as in the press, but then that's what gets it 
> in
> _Nature_ and popularized.... *Isisaurus* also has a fairly short neck, and 
> it's
> likely most saltasaurids were short-necked, given their smaller size may 
> have
> prevented long-necks from being neccessary in any sense of forage, feeding
> enveloped, etc.

Nevertheless, _Brachytrachelopan_ does seem to have an even shorter neck 
than these short-necked titanosaurs.

>   The name is rather confusing in an etymological standpoint: the Mesa 
> family's
> short-necked sheep-shepherd.

Or "the Mesa family's short-necked shepherd-god".

> <Interestingly, the cladogram shows _Amphicoelias_ as a basal diplodocoid -
> more basal than _Suuwassea_, rebbachisaurids and dicraeosaurids (like
> _Brachytrachelopan_).  This must be based on new and undescribed material 
> of
> _Amphicoelias_.>
>
>   Or a reinterpretation of the known material?

Could be - but there is not much to go on if only the type specimens for 
_Amphicoelias altus_ and _A. fragillimus_ are used.  New (and better) 
_Amphicoelias_ is known:

Wilson, J.A. and Smith, M.B. (1996): New remains of Amphicoelias Cope 
(Dinosauria: Sauropoda) from the Upper Jurassic of Montana and diplodocoid 
phylogeny. J. Vert. Paleont. 16 (3, Suppl.): 73A.

Cheers

Tim