RE: oldest sauropod found

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

The paper is:
Yates, A.M. & J. W. Kitching.  2003. The earliest known sauropod dinosaur
and the first steps towards sauropod locomotion. Proceedings: Biological
Sciences DOI 10.1098/rspb.2003.2417.  (don't know what the print data will
be).

If you can access this journal, start at:
http://www.pubs.royalsoc.ac.uk/proc_bio/proc_bio.html

Here's the scuttle-butt:
Antetonitrus ingenipes gen. et sp. nov. (the massive footed pre-thunderer),
Lower Elliot Formation (Norian), South Africa.  Based on partial skeleton of
a single individual.

>From the abstract:
A partial dinosaur skeleton from the Upper Triassic (Norian) sediments of
South Africa is described and named Antetonitrus ingenipes . It provides the
first informative look at a basal sauropod that was beginning to show
adaptations towards graviportal quadrupedalism such as an elongated
forelimb, a modified femoral architecture, a shortened metatarsus and a
changed distribution of weight across the foot. These adaptations allowed
the clade to produce the largest-ever terrestrial animals. However,
A.ingenipes lacked specializations
of the hand found in more derived sauropods that indicate it retained the
ability to grasp. Antetonitrus is older than the recently described
Isanosaurus from Thailand and is the oldest known definitive sauropod.

Interestingly, the phylogenetic analysis finds a sauropodomorpha with a
range of basal forms (Saturnalia, Thecodontosaurus, Efraasia), a
monophyletic Prosauropoda (Rioja., Plateo., Coloradi., and Lufengosaurus and
Massospondylus), and a monophyletic Sauropoda (with Anchisaurus as the
basalmost taxon!!  Anteotonitrus is above Anchisaurus and Melanorosaurus,
but below Isanosaurus and the rest.  Blikanasaurus's position is uncertain.

In any case, Melanorosaurus, Blikanasaurus, and Antetoniturs are all Norian,
and thus the oldest sauropods.  (Isanosaurus is Rhaetian).  Prosauropoda
proper (the monophyletic clade) is equally as old: Plateosaurus and an
unnamed Lower Elliot form are ALSO Norian.  Saturnalia, Azhendohsaurus, and
the two unnamed Madagascan forms are older, but none of these can be safely
placed in the prosauropod-sauropod node.

At present, the electronic appendix is unavailable, but should be online
when the print version is out (I would imagine).

                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