RE: Sauroposeidon

[tidwell@ix.netcom.com]

On 11/03/99 15:52:06 Tom Holtz writes:
>It is most assuredly not too recent for a brachiosaur, as at least SOME of
>the _Astrodon_/_Pleurocoelus_ material (contemporaneous with
>"Sauroposeidon") seems to be brachiosaurid.  Furthermore, there is now
>evidence of titanosaurs in North America by the mid-Cretaceous.

Yes, brachiosaurs have been found in the early-mid Cretaceous of Utah.  Some 
SVP attendees saw 
two new brachiosaurs from the Cedar Mountain Formation, at DMNH two weeks ago.  

Tom raises a valid point concerning the blurring of the lines defining 
brachiosaurs and 
titanosaurs.  In researching our latest specimens, I have encountered great 
frustration in 
attempting to nail down sufficiently robust characters to support proper 
identification of the  
of new taxa coming to light in the EK. But eventually, we'll get a handle on 
just what kind of 
critters we are dealing with. So, with all of the ongoing sauropod research in 
the Early - Mid 
Cretaceous, the next few years will be VERY exciting! 

Virginia Tidwell
Denver Museum of Natural History
2001 Colorado Blvd.
Denver, CO  80205
303-370-6403
tidwell@ix.netcom.com


>Of course, there is the whole question now of what other than _Brachiosaurus
>altithorax_ and _B. (sometimes _Giraffatitan_) brancai_ IS a brachiosaurid.
>It may be that "Brachiosauridae" in the old more inclusive sense includes a
>paraphyletic grade of titanosaur outgroups.
>
>               Thomas R. Holtz, Jr.