An ossified tendon trellis in Chasmosaurus (Ornithischia:Ceratopsidae). 2007. R. Holmes and C. Organ. J. Paleo. 81: 411-414.
A nice note by my old CMN colleague, Rob Holmes, and Chris Organ on a feature not previously reported for ceratopsians.
The critter is C. irvinensis. You can see a nice animation of the animal pulling itself out of its rocky matrix and walking away HERE. The video is from the display at the CMN in Ottawa.