RE: Antorbital fenestrae in troodontids

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Nicholas Gardner
>
> Hm.  HP Mahon's post has gotten me into a bit of thinking and a
> question has
> popped up.  Are maxillary fenestrae and accessory antorbital
> fenestrae the
> same thing?  If not, which is the enlarged one present in Troodontids?  I
> would assume at least that it's the accessory antorbital fenestra (AXF of
> Norell et al. 2000).

"Accessory antorbital fenestra" is the older term for "maxillary fenestra"
(prior to Witmer's new terminology). Incidentally, "secondary accessory
antorbital fenestra", or similar words, were used for the promaxillary
fenestra.

Based on the skull of _Sinovenator_ (the only troodontid to clearly exhibit
both the promaxillary and maxillary fenestrae), the enlarged opening in
Troodontidae IS the maxillary fenestra.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
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Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
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