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ceratopsian questions



Re: frills: some illustrations of ceratopsian skulls show a great deal
of vascularization, which I'm told would indicate little covering other
than skin (so heat dispersion is a plausible explanation for those
broad areas of frill).  Perhaps there are muscle- and
ligament-attachment points on certain areas of the frill, such as
around the fenestrae on the parietal/squamosal join (sorry, can't
remember the proper terminology)?

Have, or has, Rolf Johnson and/or John Ostrom published anything
recently on the ceratopsian forelimb?  They had tantalizing abstracts
published in the Society of Vertebrate Paleontology meeting issue in
1990(?) and 1991, but I haven't seen anything since.  I read the Dawn
Adams thesis (U.Cal. 1989) which posits a vertical, parasagittal
weight-bearing posture with a "sprawling" return stroke, based on
photoelastic stress analysis of models of chasmosaurine humeri, and
am curious what others are doing in that area.

And finally (for now)--could those beasties really close their beaks? 
Some of the skulls have such curved predentaries that it looks as if
the beaks would be used for grasping (or puncturing) rather than
shearing.  Some look like they might have occluded against the lower
front edge of the premaxillary, and some just look impossible (perhaps
posthumous damage, or perhaps the animal starved?)  Anyone have a good
explanation?

--Pat
centrosaurine obsessive