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

Carnosaurs, taxonomy, the usual...[Part 2]



Stan Friesen writes:

>All recent cladograms place _Ornitholestes_ well within the coelurosaur
>clade.  Greg Paul was apparently wrong about that. (Actually, if GP had
>been right it would have to have been moved to Carnosauria anyway).

        Actually, most of them place it as the first or second branch
(depending, as T.R. Holtz points out, on whether Compsognathus is used),
although there it is repeatedly referred, frequently with little
justification (see _The Dinosauria_ for details) to the Maniraptora (sensu
Gauthier).  It is not Maniraptora sensu Holtz, but is placed as a basal
Maniraptoriform, for what that's worth.  So far, all Coelurosaurs are
Maniraptoriforms except Compsognathus, and it's so weird that we probably
shouldn't count it.
        Anyway, Paul was not really wrong, he was just looking at it the
wrong way.  Ornitholestes *is* similar to Allosaurus.  There is a good
reason for this.  Allosaurus is a derived Avetheropod, but, when you cut
out the taxa referred to the "carnosaurs" (see _The Dinosauria) by coding
them individually (at which point most of them slide down the Tetanurae to
the Intertheropoda, or Spinosauroidea and Megalosauroidea), you get
allosaurs being a close outgroup of the Coelurosaurs.  Ornitholestes, as a
basal (again, not "well within") coelurosaur, *should* look a lot like
Allosaurus.
        Fun thing to do with your cladogram:  Run it with all dinosaurs
except Coelurosaurs, but including Ornitholestes.  Guess what,
Ornitholestes becomes an allosaur (and, incidentally, you can make the old
Carnosauria (sensu Gauthier) monophyletic).  And that's probably how it
looked for a million years or so in the Mid-Jurassic.
        Wagner

P.S.  Anyone willing to allow that Segnoaurs might be very late Spinosaurs?