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Re: Postosuchus/Rauisuchus



At 12:31 PM 1/9/97 -0500, Aravind wrote:

>The rauisuchids are confused with a host of other pre- dinosaurian
>archosaurs. The rauisuchids in my opinion should include the
>monophyletic assemblage of Rauisuchus, Saurosuchus, Tikisuchus,
>Fasalosuchus, Ticinosuchus (=Mandasuchus?), Heptasuchus? and possibly
>Shuvosaurus. Postosuchus which is termed as a rauisuchid is basically a
>poposaurid. Prestosuchus is also an independent form with nowhere within
>the monophyletic rauisuchids.  

Parrish's cladistic analysis of crocodylotarsan archosaurs (1993, JVP
13:287-308) includes in Rauisuchidae Lotosaurus, Fasolasuchus, Rauisuchus,
and the Kupferzell rauisuchid.  Closer to Crocodylomorpha are the
Poposauridae, containing Poposaurus, Postosuchus, Teratosaurus, and
Bromsgroveia.  The Prestosuchidae (Prestosuchus, Ticinosuchus, and
Saurosuchus) falls outside a crocodylomorph - poposaurid - rauisuchid -
aetosaur clade.

I believe Murray and Long have a different formulation for therauisuchid /
poposaurid / prestosuchid forms, but I don't have a copy of that book yet (I
know: shame, shame...), so I can't post the details.

Also, many of these forms were contemporaries (and possibly predators on)
early dinosaurs, so there are not "pre-dinosaurian".

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

"To trace that life in its manifold changes through past ages to the present
is a ... difficult task, but one from which modern science does not shrink.
In this wide field, every earnest effort will meet with some degree of
success; every year will add new and important facts; and every generation
will bring to light some law, in accordance with which ancient life has been
changed into life as we see it around us to-day."
        --O.C. Marsh, Vice Presidential Address, AAAS, August 30, 1877