Re: Bakker's Brontosaurus and Late Cretaceous populations

[Tim Williams <twilliams_alpha@hotmail.com>]

Mike Taylor wrote:

> Just to be picky --

And just to be even pickier...  :-)

> _Cathetosaurus_ Jensen 1988 was indeed sunk into _Camarasaurus_ (as the new 
> species _C. lewisi_) by McIntosh et al. 1996,

...I think this synonymy was first done by Miller, McIntosh, Stadtman and 
Gillette (1992).

Anyways, there might be reason to quibble the referral of _Cathetosaurus 
lewisi_ to _Camarasaurus_ (as _Camarasaurus lewisi_) given that the ilium of 
_C. lewisi_ is reported to be angled somewhat upwards and forwards, as in 
brachiosaurids and other titanosauriforms.  This might be a synapomorphy it 
shares with the titanosauriforms; or an autapomorphy of _C. lewisi_ within 
_Camarasaurus_; or it may mean nothing at all.  Having never seen the _C. 
lewisi_ material, I am reluctant to comment on whether the ilium was tilted 
upward in titanosauriform fashion.

> If it seems odd that the brachiosaur "Ultrasauros" should be sunk into a 
> diplodocid, that's because Jensen inexplicably nominated a dorsal as the 
> holotype of "U." instead of the indisputably brachiosaurid scapula that is 
> most associated with that name.

And apparently, the "Ultrasaurus" scapula isn't really all that large...

> The others you mentioned are less emphatic, though.  The only published 
> attempt to synonymising _Seismosaurus_ Gilette 1991 with _Diplodocus_ (so 
> far as I know) is Lucas and Heckert (2000); and all they have to say is 
> "previously misrepresented as [...] a new genus,
> _Seismosaurus_, but clearly not distinct from Diplodocus (B. Curtice, pers. 
> comm., 2000)".  I'm not particularly convinced by a pers. comm. for that,

Nevertheless, Lucas and Heckert were convinced enough to cough up the new 
combination _Diplodocus hallorum_.

> and apparently Gillette is readying a  defence of _Seismosaurus_, so I 
> suspect we've not seen the last of Sam.

Yeah!!  Go Sam!

> Curtice doesn't really commit himself one way or the other; and his 
> analysis has in any case now
> been superseded by McIntosh's (2005) new _Barosaurus_ monograph, which 
> reaffirms the genus _Supersaurus_ as distinct from _B._

Yes, AFAIK the combination _Barosaurus vivianae_ has yet to be formally 
proposed.  I haven't seen or read McIntosh (2005), so thanks for the tip.

> Hope that's helpful to someone out there.

Yes, definitely.

Cheers

Tim