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RE: The hypopubic cup



-----Original Message-----
From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of Henri Rönkkö
 
 
Archaeopteryx is said to have a hypopubic cup. Non-avian theropods, in turn, have pubic boots, even the dromaeosaurs which have most retroverted pubes. Except Rahonavis, of course. I have read some opinions according to which the differences between non-avian and avian dromaeosaurs wouldn't be so clear-cut. Could you enlighten me?
 
Thanks in advance,
Henri Rönkkö
 
The difference between a pubic boot and a "hypopubic cup" is that they have identical morphology (at least between derived non-avian maniraptorans and basal birds).  However, because those people who use the term "hypopubic cup" know a priori that these are non-homologous structures, they have to give them a different name.
 
Note that there is a LOT of diversity in pubic boot morphologies among theropods: compare the little knob of coelophysoids to the somewhat larger structure of true ceratosaurs to those of basal tetanurines to those of derived carnosaurs like Allosaurus and Neovenator and Giganotosaurus to the (proportionately) enormous pubic boots of some basal coelurosaurs like Aristosuchus and Coelurus to (whew) those of tyrannosaurids, ornithomimosaurs, oviraptorosaurs, basal alvarezsaurids, mononykines, basal therizinosaurs, derived therizinosaurs, dromaeosaurids, basal avialians, basal enantiornithines, and so on.
 

                Thomas R. Holtz, Jr.
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