Marginocephalia
Marginocephalia is a clade of ornithischian dinosaurs characterized by a bony shelf or margin at the back of the skull, a fringe that was most likely used for display. It contains two major groups: the thick-skulled Pachycephalosauria and the horned Ceratopsia. Its members were primarily herbivores, ranging from small facultative bipeds and quadrupeds in the more primitive forms to large, obligately quadrupedal animals among the more derived ones. The group first appeared in the Jurassic and became more common through the Cretaceous. The earliest marginocephalians are known from Asia, and the group later spread into North America.
Diagnosis
- Parietosquamosal shelf or frill projecting from the posterior margin of the skull
- Rostral bone at the tip of the upper jaw (in ceratopsians) or thickened skull roof (in pachycephalosaurs)
- Short postorbital region of the skull
- Reduction of the supratemporal fenestra
- Herbivorous dentition with leaf-shaped or shearing teeth
Clades within Marginocephalia
- Ceratopsia 92 genera
- Pachycephalosauria 19 genera
Genera placed directly in Marginocephalia
- Albalophosaurus Barremian (125.8–121.4 Ma)Japanincertae sedisunder dispute
- Micropachycephalosaurus Campanian (83.6–72.2 Ma)Chinaincertae sedisunder dispute
References
- Sereno, P. C. (1986). Phylogeny of the bird-hipped dinosaurs (Order Ornithischia). National Geographic Research 2(2): 234-256. sereno1986a