Skull of Pachycephalosaurus at the Denver Museum of Nature & Science. Photo © 1996 Pamela J.W. Gore, Georgia Perimeter College.
Visitors examine a Triceratops skull in the Valley Life Sciences Building, UC Berkeley campus. Photo by Dave Smith, © UC Museum of Paleontology.
The Marginocephalia ("fringed heads") are a clade of extinct herbivorous
dinosaurs that inherited a slight shelf or frill at the back of their skull from their common
ancestor back in the Early/mid Cretaceous period. This "margin" was elaborated
differently in the two main subgroups of the Marginocephalia. You are probably
familiar with some of these taxa they include the "bone-headed"
pachycephalosaurs (above left) and the frilled
Ceratopsians, such as the early
Protoceratops and the famous Triceratops (at right).
Marginocephalia is one of three major groups of the
"bird-hipped" dinosaurs. They are
closely related to the
Ornithopoda and some scientists suggest that the origin of
Marginocephalia may lie within that group, close to the