Re: Lewisuchus, a Dinosauriform

["Jaime A. Headden" <qilongia@yahoo.com>]

Ken Kinman (kinman@hotmail.com) wrote:

<Well, some workers still think herrerasaurs are basal
dinosauriforms rather than theropods, and that even Eoraptor may
be more derived than herrerasaurs.>

  This doesn't affect the position of non-dinosaurian
dinosauromorphs, which are still more primitive than
*Herrerasaurus* or *Eoraptor* (unless you have an alternative
hypothesis).

<I could be wrong, but I don't think it matters if Lagosuchus is
a nomen dubium. Family Lagosuchidae could still be the valid
family name.>

  A valid family name of what? Because *Lagosuchus* is the
definitive genus for the group, it must be included in the
diagnosis of the group. However, the type is crap and
non-diagnostic according to those who've made a point to study
the material first hand, including Arcucci, Sereno, and Rauhut.
Material formerly assigned to *Lagosuchus* has been removed on
the basis of being diagnostic but not-referrable to the type of
*Lagosuchus* because it (according to Arcucci, and Arcucci and
Sereno) cannot be compared sufficiently from any plausible
ancestor, descendant, *Marasuchus*, *Psuedolagosuchus*, and for
the most part, *Lagerpeton* (though there are differences from
the last) and as such it is a metataxon.

  Thus, *Lagosuchus* and it's group, Lagosuchidae, are useless
phylogenetically (and this was done without cladistics, too; see
Arcucci and Sereno, 1993 and 1994, in successive issues of JVP
[13(4) and 14(1) respectively]....).

=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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