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RE: Pterosaurs and ABSRD (sensu Williams)



> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> HPB1956@aol.com
>
> There seems to be growing proof that pterosaurs are derived
> prolacertiforms.
> If correct this would blast, sorry, move pterosaurs out of
> Archosauria and
> even Archosauriformes.
>
>  Quite a distance phylogenetically. I think this underlines again the
> importance of known basal members of a taxon.

*BING*  Good answer!!

> Reminds me of e.g. moving Tyrannosauria outside
> Maniraptoriformes and Troodontidae into Maniratora (thus killing
> Arctometatarsalia?).

Not really, as "Arctometatarsala" = "_Ornithomimus_ and everything closer to
it than to Neornithes".  Thus, in my present phylogeny (or those of, say,
Makovicky & Sues in the _Microvenator_ paper), Arctometatarsalia comprises
only Ornithomimosauria among known taxa.

> But Pterosauria is an extreme case.

Not really.  It's not like turtles, which are bopping between
Lepidosauromorpha and Archosauromorpha and the parareptile groups.  Or like
the basal structure of Eutheria (Xenarthra outside of epitheres, and a
monophyletic Ungulata containing tethytheres, artiodactyls, and
perissodactyls (among others) vs a basal split between a
xenarthran-afrotherian clade and Carnivora closer to Perissodactyla than
either are to Artiodactyla).  Or how about non-angiosperm seed plant
relationships...

>  Regarding the capability of development of hairy or feathery
> integument: if
> pterosaurs did it and dinosaurs too, why not other archosaurs
> phylogenetically in between these? Would be nice to find some
> fossil of e.g.
> Euparkeria with some kind of integument.

Sure would.  Of course, if pterosaurs are derived prolacertiforms, we DO
have the integument of living archosaurs phylogenetically between pterosaurs
and dinosaurs: namely, crocodilians.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796