J is for Judiceratops
Judiceratops tigris was a chasmosaurine ceratopsid from the Late Cretaceous of Montana, USA, living about 78 million years ago. Announced just a few months ago in early 2013, it’s significant for being the earliest known example of a chasmosaur, a group that includes one of the most famous dinosaurs of all, Triceratops.
The purpose of ceratopsids’ elaborate horns and bony head frills is still unclear. Being relatively fragile in many species, they probably weren’t much use as a defense against predators – so it’s likely they functioned much like horns and antlers in modern ungulates, used in sexual selection and display.