re: Where have all the ornithischians gone?

[David Peters <davidrpeters@earthlink.net>]

tim williams wrote;

And then there's _Technosaurus_, from the Late Triassic (Norian) of
Texas. I had thought the original
material included both ornithischian and sauropodomorph material, and a
putative ornithischian dentary
was designated as the lectotype. Or am I way off-base and/or out-of-date
about this?


>>>>

This is the kind of material that needs to be looked at with the eye
that MAYBE  the pubis is not retroverted in this taxon, (Is that why it
appears to be mixed up with sauropodomorph material? I don't know and
haven't seen).

Silesaurus is definitely on the list of ornithischians without a
retropubis.

So is Lotosaurus. If you squint (or use PAUP) you can still see the
fabrosaur/pisanosaur in its skull, general proportions and limbs. Teeth
are gone but that happens. So what if it's quadrupedal? Lots of
ornithischians go that way. Pisanosaurus has long enough arms to form a
basal taxon of soon to be quadrupeds. The tarsus is bigger than what you
might expect to see in a dinosaur, but remember its very basal, only a
taxon or two away from crocs. Sure it has autapomorphies, but you'll
find that Lotosaurus is not closer to any other diapsid.

If we had a clade called Paraornithischia, we wouldn't need an 'incerta
sedis' for these taxa.

Of course, then, all of the mystery and some of the fun would disappear.

David Peters
St. Louis