List of marginocephalian type specimens
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This list of specimens is a comprehensive catalogue of all the type specimens and their scientific designations for each of the genera and species that are included in the clade marginocephalia.
Marginocephalia is a clade of ornithischian dinosaurs that includes some of the most well-known Mesozoic animals, such as Triceratops and Pachycephalosaurus. The group is united by, and is named for, the presence of a bony margin formed mostly from the parietal and squamosal bones at the posterior end of the skull. Although the first marginocephalian known to scientists, Agathaumas, was described in 1872 by Edward Drinker Cope,[1] the clade itself was not recognized until the latter part of the 20th century when Paul Sereno first united the two major groups, ceratopsians and pachycephalosaurians into a single clade.[2]
Marginocephalians first appeared in the Jurassic period as small bipedal animals.[3] However, they saw an apparent increase in diversity during the Early Cretaceous period which culminated in the emergence of megafaunal forms by the end of the period that weighed in excess of five metric tons.[4] Most of their diversity is known from North America and Asia, with a few remains attributed to the group from Europe,[5] South America,[6] and Australia.[7]