RE: Herrerasaurus ... again

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

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of B tH
>
> Does anyone know of any recent work done on the "direct" 
> ancestor of this early dino?
> 
> I'm intrigued by this guy because he was so (relatively) big. 
>  If H is considered one of the earliest known dinos, then 
> there must be something still in the ground or undescribed at 
> this point that indicates a smaller, earlier form, right?

Herrerasaurus, Eoraptor, Panphagia, and Pisanosaurus are all the same age,
and indeed from the same unit. At present there are know dinosaurs known
which are definitively older: they must exist, but haven't been found yet.

There are some intriguing footprints from Argentina in the Middle Triassic
that *might* be dinosaurian, but they could be from a close sister group (or
from yet another damn dino-mimic among the crurotarsans... No evidence for
that yet, but you can't trust those stem-crocs ;-).

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
http://www.geol.umd.edu/~tholtz/
Fax: 301-314-9661               

Faculty Director, Earth, Life & Time Program, College Park Scholars
http://www.geol.umd.edu/~jmerck/eltsite/
Faculty Director, Science & Global Change Program, College Park Scholars
http://www.geol.umd.edu/sgc
Fax: 301-314-9843

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA