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Re: ORNITHISCHIANS :-)



  I'm replying too much for my own good, I can feel the negative
karma building.

George Olshevsky (Dinogeorge@aol.com) wrote: 

<AFAIK, we do not have the pubis; we have a >matrix impression<
of a pubis that has been prepared away(!) so that only a sketch
diagram remains, so that could well be a prepubic process rather
than a propubic pubis.>

  Not even *Lesothosaurus* or *Heterodontosaurus* have a
preopubic process. It is not likely that the prepubic process
points ventrally, either, unless this is an apomorphy of
*Pisanosaurus*. It can be very possible that even the base ornie
had a propubic pelvic orientation, as this is the case with
every dinosauromorph except *Herrerasaurus* and ornithischians
higher than *Pisanosaurus,* and the eumaniraptorans (and let's
not forget the segnosaurs!); as it is a very early ornithischian
(almost Mid-Triassic), is it not possible to have a propubic
orientation?

<They're close-packed and lack a cingulum, and quite strongly
resemble the teeth of heteros and psittacosaurs. Detailed
comparison is badly needed.>

  Anything that isn't an ankylosaur, stegosaur, and some
ornithopods, lack a cingulum. The teeth are not as close-packed
as heterodontosaurs, or *Lesothosaurus,* and the distal and
mesial margins of the teeth are apparent in lateral view.
 
<Heteros almost certainly had a Late Triassic evolutionary
history, presently unknown or represented by a few misc teeth.>

  The Upper Stormberg is Late Triassic, Rhaetic I beleive. So
*Heterodontosaurus* and *Lycorhinus* along with Moroccan
*Abrictosaurus* are LT taxa as well.

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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