[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: _Turanoceratops tardabilis_



In a message dated 96-02-24 21:41:16 EST, Stang1996@aol.com writes:

>So there are genuine Ceratopids running around Asia?  Weird!  This really
>puts a wrench into theories of where Ceratopids evolved; did
>"Protoceratopids" migrate to North America, evolve into Ceratopids and then
>migrate back?  Or did Ceratopids evolve in Asia and migrate to North America
>and become terribly successful, with only a few "Protoceratopids" migrating
>with them, not evolving into anything?  The second case, in my opinion, is
>the better of the two; but then again, that's my opinion.  I put
>"Protoceratopidae" in quotes because I believe it to be paraphyletic.  Also,
>Has the pterosaur previously called _Ornithodesmus_ been renamed?

Nessov provided a couple of drawings of skulls (_Asiaceratops_,
_Turanoceratops_) with the bits and pieces in place. _T._ has the best chance
of being a ceratopid; the nasal and supraorbital horn cores do resemble those
of pachyrhinosaurines. But note the ages of the specimens--quite a bit
earlier than the ages of the North American forms. I'd say, if Nessov's
concepts pan out, that the pachyrhinosaurines evolved in Asia, then headed
east to North America. But it is odd that no ceratopids are known from
Mongolian and Chinese later Cretaceous localities, only protoceratopids.
(Yes, Protoceratopidae _sensu lato_ is paraphyletic, but the known genera
seem to form a monophyletic clade within this Protoceratopidae _sensu lato_,
and most authors refer only to that clade as Protoceratopidae, keeping things
monophyletic. It's the sister group of Ceratopidae within Neoceratopia.
_Turanoceratops_ might be a neoceratopian that is neither protoceratopid nor
ceratopid but located along the stem of Ceratopidae.)

No, the new pterosaur genus represented by _Onithodesmus latidens_ has not
yet appeared in print as far as I know. (Darren Naish??) It is supposed to be
described by Howse.