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Re: Thunder-Lizards



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