Re: Holes in Frills

[Nick Longrich <longrich@stardot.com>]

On Thu, 5 Dec 1996 gpb6845@msu.oscs.montana.edu wrote:

> Possibly, but if that's the case, it makes one wonder why Triceratops
> closed up it's fenestrae when it's frill was proportionally as big (if
> not bigger) than most Centrosaurines.  I happen to think GSP's
> assertations in Dinosaurs Past and Present II (and possibly elsewhere)
> that the jaw muscles of ceratopians probably extended to nearly the
> end of the frill and that the peculiar "tounges" of bone in
> Centrosaurus' (or Monoclonius' or Eucentrosaurus' or whatever the hell
> they call it now) frill

        A while back I took a look at an AMNH Centrosaurus skull. I am 
not an expert but I came away completely convinced that the 
muscle-attachment hypothesis was wrong. The reason is that the spikes 
looked just like the hornlets around the frill, and this would be very 
puzzling if they supported muscle instead of horn. 
        Also it seems strange that this feature, if highly functional, is 
not found in more centrosaurines, centrosaurines seem to have been much 
more consevervative in their general anatomy than they were with display 
features. 
        The frill in general may also have served the purpose of 
protecting the neck from the bites of tyrannosaurs. Notice the heavy neck 
armor seen in nodosaurs and ankylosaurs, which was more than likely not 
used to protect against damage during intraspecific combat. There was an 
asian ankylosaur ( it was at the Russian dinos exhibit; can't remember the 
genus) which has taken its eight neck  spikes and fused them into a 
massive pair of half-circular collars each  bearing four low, stout 
spines. Neck armor may have been very important in the late Cretaceous.

        Nick L.