Re: Rauhut's Thesis

["Mickey Mortimer" <Mickey_Mortimer11@msn.com>]

ekaterina amalitzkaya wrote-

> Fascinating treatise by Dr. Rauhut. Many question apart from the most
> general one how much can the matrix preparation be trusted.

I trust the matrix more than most other theropod matrices, as Rauhut has
seen nearly all specimens (or casts of them) firsthand and includes a list
of these.  Also, there is a very long section describing the characters that
gives examples of specimens or publications that show the presemce of each
character in each taxon.  My own experience coding "segnosaurids" for my
upcoming post has shown me at least that taxon's coding is completely
accurate.

> So this part of the tree appears to be an artefact arising through the
> inclusion of Shuvosaurus- the Coelophysids should be monophyletic. So Dr.
> Rauhut has now refuted the idea that Shuvosaurus may be a Lotosuchus like
> basal archosaur?

"An artifact" would suggest that the topology was incorrect.  More taxa
should always be included if they are complete enough (Holtz, 2000).
Shuvosaurus is a theropod based on- inverted L-shaped and exposed on the
skull roof; presence of a deep basisphenoid recess; ectopterygoid with
expanded medial part and deep ventral fossa.  It does not resemble
Lotosuchus ecept for being toothless.  You can read Rauhut's detailed
reasoning as to Shuvosaurus' relationships here-
http://blackwidow.informatics.sunysb.edu/anatsci/files/Rauhut_97.doc

> Does Dr. OR
> mention anything about the new Jurassic theropods he discovered recently?

Which ones would those be?

> This part is somewhat Sereno like? what was the fate of Cryolophosaurus in
> Dr. ORs analysis?

Cryolophosaurus was not included because the association of postcrania with
the skull is still uncertain, the initial description is very brief and
Oliver's attempts to see the material were unsuccessful.

> Have you tried removing Acro to see if it affects the picture in any way??

Nope.  Been too busy with other things, but sounds like a good idea once I
get some time.

> Some years ago Dr. OR
> had published a little paper on a sickle claw, teeth and pedal elements
from
> Sudan. May be he could enlighten us as to whether this was Troodont or a
> Dromaeosaur. Would the presence of these in Africa not be unexpected by
the
> current paleogeographical considerations?

(sorry if Oliver wanted to answer this, as it is addressed to him).  The
Sudanese material is not troodontid, but rather deinonychosaurian (in my
phylogeny of (Trood (Drom, Aves)) anyway).  The teeth have much larger
posterior serrations than anterior serrations ("velociraptorine") and
smaller serrations than troodontids.  A deinonychosaur in Africa is not
unexpected, as they are present in Argentina (Megaraptor) and England
(Nuthetes, Ornithodesmus) at about the same time, and these faunas had much
in common.

> So were there Deinonychosaurs in South America or India? If the relative
> large Unenlagia is not exactly a Deinonychosaur and closer to the birds
but
> not one as yet then what exactly was it. Should we not expect similar
forms
> in SA and Ind are there any indications of such?

No coelurosaurs have ever been verified from India, although Weishampel et
al. (1990) lists ornithomimid remains (perhaps alvarezsaurid or small
abelisauroid?).  Megaraptor seems to be a deinonychosaur
(http://www.cmnh.org/fun/dinosaur-archive/2001Feb/msg00415.html), and there
is a second taxon closely related to it (Martinez, Lamanna, Smith, Casal and
Luna 1999) from the Bajo Barreal Formation.

Mickey Mortimer