[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

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.

Shuvosaurus inexpectatus

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 

Pieter Depuydt