RE: Antarctosaurus mandible

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Marco Auditore
>
> Hi to all dinolist members.
> I want to know if, in light of the discovery of the new titanosaur
> Rapetosaurus, is possible that the partial dentary originally assigned by
> Von Huene to Antarctosaurus wichmannianus, and then assigned to the
> rebbachisaurids, was in fact the mandibles of Antarctosaurus or, at least,
> of titanosaurian nature.

Although that does remain a possibility, the A. wichmannianus mandible
shares features with Nigersaurus that are not found in titanosaur skulls
(like Rapetosaurus):
*The teeth are arrayed in rows only along the anterior margin (not unlike
grazing rhinos, among other taxa); in Rapetosaurus the teeth extend down
most of the length of the dentary
*The dentary forms a real nice right angle between the tooth-bearing surface
and the ramus leading posteriorly to the post-dentary bones; in Rapetosaurus
(and other titanosaurs), the dentary is more gently curved.

So the weight of the evidence points to A. wichmannianus being a
rebbachisaurid.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796