Ceratopsian Frills

[Amado Narvaez <anarvaez@umd5.umd.edu>]

I was looking through my copy of _Dinosaurs, Mammals and Cavemen: The Art 
of Charles R. Knight_ and something about the classic T. rex vs 
Triceratops mural prompts this question. In the "old days" the frill of 
ceratopsians was a smooth, curving line. Many artists and animators 
today, however, show the frill as having triangular features. In the 
Lambert book _The Ultimate Dinosaur_ they're called "epocipital bone," 
which is also used to describe the "horns" on the frill of Styracosaurus. 
Is there really evidence for epocipital bone on the frill of Triceratops, 
or is this artistic interpretation? Is epocipital bone characteristic of 
all the ceratopsians, including Protoceratops?

----- Amado Narvaez
      anarvaez@umd5.umd.edu