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Re: Gondwanan theropods: new papers by Novas and colleagues



Thomas Holtz wrote-

> However, the pubic anatomy of Unquillosaurus is
> more congruent with that present in metornithine coelurosaurians, a group
> including Alvarezsauridae, Therizinosauroidea, Oviraptorosauria,
> Deinonychosauria, and Aves. Derived features present in Unquillosaurus
> include: opisthopubic pelvis, pubic pedicle of ilium craniocaudally wide,
> ventral margin of pubic pedicle strongly concave, cranial process of pubic
> foot short, and length of pubic foot less than 30 percent of pubic total
> length. Moreover, some traits shared with early avians (e.g., pubic foot
> proximodistally tall and craniocaudally short), suggest that this dinosaur
> may be more closely related to birds than suspected.

Hmm.  Not sure what I think about this.  Some non-maniraptoriformes have
many of these characters too.  Taxa like Yangchuanosaurus, "Szechuanoraptor"
and Piatnitzkysaurus have pubes angled only 15 degrees forward from
vertical.  Many tyrannosaurids' pubes have a proximal shaft only 5 degrees
forward or less from vertical, and other basal coelurosaurs are similar.
Most tetanurines have anteroposteriorly elongate pubic peduncles.
Gorgosaurus (Lambe, 1917) is an example of a more basal taxon with a concave
pubic peduncle.  A reduced cranial pubic boot is plesiomorphic for
tetanurines (Piatnitzkysaurus, "Szechuanoraptor", megalosauroids,
Monolophosaurus, Marshosaurus, sinraptorids, compsognathids, Coelurus,
etc.).  A similar statement could be made for pubic boot length, which only
reaches >30% in groups like allosaurids, Giganotosaurus, tyrannosaurids and
some basal coelurosaurs.  I always figured the cross-hatching in Powell's
illustration meant the pubic boot was broken posteriorly.  Finally, taxa
like Allosaurus and tyrannosaurids have pubic feet that are as
proximodistally tall as Unquillosaurus.  I'll have to see the paper for a
final opinion though.
For my two year old opinion on Unquillosaurus, see
http://dml.cmnh.org/2002Aug/msg00397.html .

>  1) Indosuchus and
> Indosaurus are abelisaurids, as recognized by previous authors, but
> available information is not enough to judge whether they are synonyms; 2)
> Laevisuchus indicus is a small abelisauroid, related to Noasaurus and
> Masiakasaurus on the basis of their peculiar cervical vertebrae; 3) the
> controversial taxa "Compsosuchus", "Dryptosauroides", "Ornithomimoides",
and
> "Jubbulpuria" are represented by isolated vertebrae corresponding to
> different portions of the neck and tail, and also exhibit abelisauroid
> features;

Anyone else confused by the lack of any reference to Coeluroides?  Think it
was lost?

Mickey Mortimer
Undergraduate, Earth and Space Sciences
University of Washington
The Theropod Database - http://students.washington.edu/eoraptor/Home.html