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Re: SHUVOSAURUS INEXPECTATUS the story
Shuvosaurus again popped up on the list, and rather than arguing
about Dr. Chatterjees idea's and respectability, I'd choose to give
the whole story of Shuvosaurus as it has been published thus far.
Each may draw his own conclusions.
Genus and species established on a nearly complete small skull (17cm
long) with lower jaw and a dorsal vertebra; referred material consists
i.a. of a second partial skull with atlas, anterior part of two
dentaries, a vertebral arch and a right scapula. All material was
recovered from the Upper Dockum, near the town of Post in Texas,
together with remains of metoposaurs, aetosaurs, prosauropods,
phytosaurs, and (importantly,see further) rauisuchians and poposaurs.
(Chatterjee: Shuvosaurus, a new theropod. National Geographic Research
& Exploration 9(3), p 274-285; See also Glut's Dinosaur Encyclopedia
under the appropriate heading)
Chatterjee placed S. in Ornithomimosauria on the basis of several
characters (jugal reduced, edentulous jaws, postorbital extended to
ventral level of orbit, quadrate strongly inclined, descending
anteriorly, lower temporal opening reduced to a vertical slit, upper
temporal opening depressed from skull roof to occiput, supraoccipital
with dorsolateral concavities. Chatterjee noticed even three
synapomorphies which S. shared with Dromiceiomimus: frontal
participating in formation of orbital rim, lower temporal opening
subdivided by forwardly projecting bar of quadratojugal, antorbital
fossa extending forward to the premaxillary contact. Chatterjee
allowed however for an alternative phylogenetic interpretation of S.:
that it could be an independent Triassic convergence of the
ornithomimosaurian skull morphology.
This alternative scenario was advocated by Long and Murry, who were
of the opinion that Chatterjees assignment of Shuvosaurus to
Ornithomimosauria, based solely on cranial characters was rather
weakly supported (they don't go in much further detail, mind you).
Long and Murry remarked that the Shuvosaurus skull matched in size,
proportions and presevation the holotype skeleton of the lightly
build and highly derived rauisuchian Chatterjeea elegans, found at
the same locality and completely headless. They also mentioned the
find of a Chatterjeea ilium together with an edentulous right
premaxilla, very similar to the Shuvosaurus one, in a bone
concentration of Revuelto Creek. Long and Murry however recognized
their statement could be proved as yet, and kept the genera
Shuvosaurus and Chatterjeea as distinct.
(Long and Murry: Carnian and Norian tetrapods of the American
Southwest. NMMNH Bulletin 1997).
Hope this adds to the discussion