Re: Theropod Questions

["Scott Hartman" <scott_hartman@hotmail.com>]

(1) What did oviraptorids eat? I have read that eggs, molluscs (shellfish), 
live vertebrates and carrion as possibilities. Could the jaws be used to 
break open bones?

    I've always favored an omniverous ratite-like diet.  However, the 
remains of a  lizard and a juvenile dromaeosaur have been found in oviraptor 
nests, which is suggestive of a more meat oriented diet, (although the 
dietary meat/plant ratio could have changed through ontogeny, perhaps wiht 
more meat being comsumed during youth, whne high growth rates may have 
created higher nutritional requirements).  Oviraptors do have fairly strong 
jaws, so cracking thin-walled bones seems possible.  On the other hand, the 
bizzare jaws don't open as wide as other theropods, so this activity would 
be restricted to small diameter bones.

(2) Did compsognathids (Compsognathus+Sinosauropteryz), Coelurus and
Ornitholestes have a semilunate carpal?

   Actually, even in _Allosaurus_ the homologous carpal serves as a poorly 
developed functional analog, and tthe similarity is greater in 
compsognathus.  In phylogenetic terms, however, I believe the semi-lunate 
carpal is restricted to maniraptorans.  I'm sure Tom Holtz can shed light on 
this.

(3) Why was the semilunate carpal enlarged in oviraptorosaurs and
deinonychosaurs?

   The semilunate carpal allows lateral flexion of the hand. As I metioned 
above, this is possible (to a greatly reduced degree) in allosaurs, but the 
extreme development in dromsaesaurs and oviraptosaurs is (at least 
primatively) most likely to keep large arm feathers out of the way when not 
in use.

Hopefully this is useful to you.

Scott Hartman

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