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Relevant to the earlier discussions of the snout of Utahraptor:
A quick scan of the figures in _The Dinosauria_ (Weishampel et al.,
figures from Ostrom's original work on the genus) shows Deinonychus
[sic?] with a "keyhole-shaped" orbit similar to Allosaurus and a
steeply sloped, smooth, ventrally convex upper rostral margin (the
nasals curve down to a small premaxilla). Paul, in _Predatory
Dinosaurs of the World_, shows Deinonychus (Velociraptor) with a V.
mongoliensis-like narial crest extending above less inclined nasals,
and a large, square orbit.
Examination of the figures show that Deinonychus' frontal, the bone
which would determine the width of the dorsal margin of the orbit, and
the posterior process of the Maxilla, which would determine the length
of the snout and therefore the shape of the snout, were both unknown.
Also, the lacrimal, forming the anterior margin of the orbit, looks
like it could very easily be interpreted as articulating in a more
vertical position, giving the animal a larger, square orbit. In fact,
for the Ostrom orbit to work, the frontal would have had to be much
smaller than is figured for related species (Velociraptor (Paul,
ibid.), Dromaeosaurus (Weishampel et al., ibid.), Archaeopteryx (Paul,
ibid., and a paleo text I cannot recall at present)).
As an aside, the sclerotic [sic again?] ring mounted casts of
Deinonychus is about half the diameter of that figured by Paul. I
believe the ring was reconstructed in both cases. I the former case,
it leads to a positively tiny eye, much smaller (relative to skull
size) than in other dromaeosaurs and Archaeopteryx, which is obvious
in any restoration of the Ostrom "morphotype".
Does anyone have any insight as to how this confusion has come about,
and/or what the resolution is?
Jonathan R. Wagner