Spiclypeus

Phylogeny: Dinosauria > Ornithischia > Genasauria > Neornithischia > Cerapoda > Marginocephalia > Ceratopsia > Neoceratopsia > Coronosauria > Ceratopsoidea > Ceratopsidae > Chasmosaurinae

Overview: With its enormous head, bony frill and numerous horns, Spiclypeus is a good example of a dinosaur in the family Ceratopsidae. Ceratopsids were the most derived members of the larger clade Ceratopsia. Members of said lineage started out as mostly small and bipedal creatures, in most cases lacking such large frills or horns, though all had parrot-like beaks. Spiclypeus and its kin, due to having such gigantic skulls, had evolved quadrupedal movement, though this trait appeared fairly late into the evolution of ceratopsians. Ceratopsids are most easily distinguished from each other by their cranial ornamentation, which was often unique to each species or genus. Spiclypeus possessed a frill with a notable forward bend towards its apex, fringed by triangular hornlets (epiparietals). On its snout was a fairly small horn, though above its brow was a pair of slightly longer ones. These features acted as both defensive and display structures, to ward off predators or rivals among its own kind.

Spiclypeus belonged to the ceratopsid subfamily Chasmosaurinae. Chasmosaurines tended to have longer, narrower snouts and more elongated frills. These frills usually had large, paired openings which were covered by tissue and skin in life, which made them not overly useful for defense (these fills possibly had striking patterns or other such display features). Being a chasmosaurine made Spiclypeus a close relative of the famous Triceratops, which also belonged to this subfamily, though it was a lot more derived than this genus. Spiclypeus was most closely related to ceratopsids like Kosmoceratops and Pentaceratops. Described as a genus in 2016, Spiclypeus takes its name from Latin, meaning “spiked shield”, in reference to its spined frill. Fossils of the animal were first unearthed in what is now Montana, in the mid-2000’s, from rock layers of the Judith River Formation. It coexisted with other herbivores including fellow ceratopsids, hadrosaurs and pachycephalosaurs, as well as carnivores like Gorgosaurus and Daspletosaurus (two large tyrannosaurid genera).