Re: RE:Elaphrosaurus and Abelisaur taxonomy

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

>       Elaphrosaurus:  Ok, boss, but are you SURE it's not
>tetanuran?

(Relatively) certain.  In my dissertation, it came out as a basal
tetanurine, but all my more recent analyses (as well as those of
Sereno et al.) find it to be a ceratosaur, as Paul suggeted in PDW.

>       Poikilopleuron and Megalosaurus synonymized?

I'll wait on this until Laura Canning publishes.

>       Torvosaurus:    Yes it's claws may be massive, but what
>good could they be in a running (or running/jumping) attack?
>Does anyone have any ideas about how it would use them arms?

Good question, but they had one hell of a grip!

>       Abelisaurid orbits:  Senor HolTz, I think you missed my
>point, which was, admittedly, a weak one.  The Abelisaurid
>Orbital bar continues the margin of the upper orbit in a
>smooth circle, curving upwards.  Tyrannosaur and Acrocanthosaur
>orbital bars don't seem to do this (except for, if memory
>serves, an Albertosaur (A. sarcophagus?) figured by Paul in
>_PDW_), but instead they bulge out in a lump from the
>postorbital bar.

True.  In all these cases, however, this may form the bottom edge of
the muscle attachments for the eye.  Abelisaurids are simply more
specialized in this.

>       I still cannot recall which, but either
>Eustreptospondylus or Piatznykisaurus appears to be VERY similar to
>to other alleged "megalosaurs".

As you noted before, the plexus of basal tetanurines have a lot of
symplesiomorphies, but very few (recognized) synapomorphies on which
to hang a clade.

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

"There are some who call me...  Tim."