Re: Re:Abelisaur & Titanosaur migratory routes

[Thomas_R_HOLTZ@umail.umd.edu (th81)]

>>1) No Abelisaur or Titanosaurs have been found in the northern parts of
>>North America and Asia with any certainity.  
>
>Oke
>
>>2) Assumption made that Abelisaurs & Titanosaurs originated in South
>America.
>
>Why this assumption the oldest Abelisaurid i know of is Tarascosaurus
>salluvicus (Theropoda Neoceratosauria Abelisauridae)  from the Cretaceous
>Late Campanian (83 74 MYA) found in the Fuvelian Beds, ?Bouche-du-Rhone,
>France Europa. While Abelisaurus comahuensis   (Theropoda Neoceratosauria
>Abelisauridae ) is from the Cretaceous Late Maastrichtian (74 65 MYA) of the
>Allen Formation, Rio Negro, Argentina, so later. 

Carnotaurus sastrei, one of the two original members of Abelisauridae, is
Albian (and has been known to be Albian for quite some time).
>
>And the "oldest" Titanosauridae i know Atlantosaurus montanus, is from the
>Late Jurassic Tithonian (152.1 145.6 MYA) from the US and Canada while all
>the South American Titanosauridae are from the Late Cretaceous.
>
The titanosaurian nature of Atlantosaurus is subject to debate, to say the
least.  Furthermore, almost all the dinosaur bearing horizons of the
Morrison are now known to be Kimmeridgian (a recent development,
though, not widely reported yet).  However, Janenschia of the Tendaguru, IS
a Late Jurassic titanosaurian.


Thomas R. Holtz, Jr.
Vertebrate Paleontologist
Dept. of Geology
University of Maryland
College Park, MD  20742
Email:Thomas_R_HOLTZ@umail.umd.edu (th81)
Fax: 301-314-9661
Phone:301-405-4084