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Re: What came before Eoraptor?...was:Re: [Fwd: MEGALANCOSAUR notes from Ruben.

Larry Febo wrote-

> Even so,...has anyone postulated what group may have held the ancestors
> Eoraptor? If prolacertiforms have all these "birdlike" characteristics,
> addition to preorbital fenestrae, and possible bipedal posture as seen on
> Dave Peter`s website:
> http://home.stlnet.com/~azero/Pterosaur_Origins.html  )
> Then it would appear (to me) that they would make pretty good candidates
> predinosaurian forms, even if one didn`t go for the "trees down"
> Can anyone suggest a better group?

Assuming Eoraptor is a basal dinosaur and not a basal theropod, which is
currantly controversial, the next outgroup to the Dinosauria would be
Pseudolagosuchus.  Going further down the tree brings you to Marasuchus,
then to Lagerpeton.  Lagosuchus belongs somewhere in this group, as may
Saltopus (though this genus's position is far from certain) and Lewisuchus
(which has also recently been classified as a crurotarsan).  A dinosaur
possibly phylogenetically close to Eoraptor is Guiabasaurus, although the
two have never been in an analysis together.  The next closest outgroup to
the Dinosauria after Lagerpeton may be the Pterosauria, although some people
think they were related to prolacertiforms instead.

Mickey Mortimer