From: "Jaime A. Headden" <qilongia@yahoo.com>
To my knowledge, one specimen, a hadrosaurine (*Edmontonia annectens*) shows this, otherwise it has not been reported.
Jordan Mallon
Undergraduate Student, Carleton University Vertebrate Paleontology & Paleoecology
Paleoart website: http://www.geocities.com/paleoportfolio/ AIM: jslice mallon