Re: Thunder-Lizards

[Tim Williams <twilliams_alpha@hotmail.com>]

Mike Taylor wrote:

> You have read Remes's SVPCA abstract on the web-site?
> http://www.svpca.org/years/2004_leicester/abstracts/svpca-papers_a.htm#abst60

To quote from Remes' abstract:

"The existence of the North American genus Barosaurus in Africa is 
surprising, since terrestrial faunal exchange between Laurasia and Gondwana 
during the Late Jurassic is considered improbable due to marine barriers."

This could also undermine the notion that _Brachiosaurus altithorax_ 
(Morrison) and _Brachiosaurus brancai_ (Tendaguru) belong in the same genus. 
 And I know how much Mike loves the name "Giraffatitan"!  :-)

> From a previous message:

> ["_Gigantosaurus_" _africanus_ = "_Barosaurus_" _africanus_ = _Tornieria 
> africanus_, the latter combination proposed independently by Remes, 
> presented at SVPCA 2004, and by Upchurch et al. 2004. "_Gigantosaurus_" 
> _dixeyi_ = _Malawisaurus dixeyi_.  "_Gigantosaurus_" _robustus_ = 
> _Janenschia robusta_ =? _Tendaguria_.  I think that about wraps it up for 
> "_Gigantosaurus_" :-) ]

Very nicely.  And I think you're right on the money when you suggest that 
_Janenschia_ and _Tendaguria_ might be the same after all.  _Janenschia 
robusta_ is known from limb bones, and _Tendaguria tanzaniensis_ is known 
from presacral vertebrae that were previously referred to _J. robusta_.  
Both the limbs and the vertebrae come from a VERY heavily-built sauropod.  
The caudal vertebrae are procoelous, and (like the presacrals) were removed 
from _J. africana_ by Bonaparte et al. (2000).  The latter study split the 
material three ways (limb bones, dorsals, caudals), due to their lack of 
association.  This is probably the best course of action until further 
material can prove that the limb bones +/- presacrals +/- caudals belong in 
a single taxon.

_Janenschia_ is currently regarded as a titanosaur based upon characters in 
the limb bones (contra Bonaparte et al. [2000] who suggested camarasaurid 
affinities).  The pronounced procoely of the caudals is also consistent with 
titanosaurs.  _Tendaguria_ shows a combination of basal sauropod and 
neosauropod characters in the presacral vertebrae.  The dorsals of 
_Tendaguria_ are certainly very weird, with short neural spines and enormous 
transverse processes.

Cheers

Tim