Cerapoda ("ceratopsians" and "ornithopods") is a clade of the

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

order Ornithischia, that includes

pachycephalosaurs Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, most pachycephal ...

ceratopsians Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic ...

and

ornithopods Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world ...

Classification

Cerapoda is divided into two groups:

Ornithopoda Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (), that started out as small, bipedal running grazers and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous worl ...

("bird-foot") and

Marginocephalia Marginocephalia (/mär′jə-nō-sə-făl′ē-ən/ Latin: margin-head) is a clade of ornithischian dinosaurs that is characterized by a bony shelf or margin at the back of the skull. These fringes were likely used for display. There are two clad ...

("fringed heads"). The latter group includes the

Pachycephalosauria Pachycephalosauria (; from Greek παχυκεφαλόσαυρος for 'thick headed lizards') is a clade of ornithischian dinosaurs. Along with Ceratopsia, it makes up the clade Marginocephalia. With the exception of two species, most pachycepha ...

("thick-headed lizards") and Ceratopsia ("horned faces"). The following taxonomy follows Richard J. Butler, Paul Upchurch and David B. Norman, 2008 (and Butler ''et al.'', 2011) unless otherwise noted. Cerapoda was first named by Sereno in 1986 and defined by him as "'' Parasaurolophus walkeri'' Parks, 1922, '' Triceratops horridus'' Marsh, 1889, their most recent common ancestor and all descendants". In 2021, Cerapoda was given a formal definition under the

PhyloCode The ''International Code of Phylogenetic Nomenclature'', known as the ''PhyloCode'' for short, is a formal set of rules governing phylogenetic nomenclature. Its current version is specifically designed to regulate the naming of clades, leaving the ...

: "The smallest clade containing ''

Iguanodon bernissartensis ''Iguanodon'' ( ; meaning 'iguana-tooth'), named in 1825, is a genus of iguanodontian dinosaur. While many species have been classified in the genus ''Iguanodon'', dating from the late Jurassic Period to the early Cretaceous Period of Asia, Eu ...

'' Boulenger in Beneden, 1881, ''

Pachycephalosaurus wyomingensis ''Pachycephalosaurus'' (; meaning "thick-headed lizard", from Greek ''pachys-/'' "thick", ''kephale/'' "head" and ''sauros/'' "lizard") is a genus of pachycephalosaurid dinosaurs. The type species, ''P. wyomingensis'', is the only known species, ...

'' (Gilmore, 1931), and '' Triceratops horridus'' Marsh, 1889."Madzia D, Arbour VM, Boyd CA, Farke AA, Cruzado-Caballero P, Evans DC. 2021. The phylogenetic nomenclature of ornithischian dinosaurs. ''PeerJ'' 9:e1236

/ref> The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

below follows a 2011 analysis by paleontologists Richard J. Butler, Jin Liyong, Chen Jun and

Pascal Godefroit Pascal Godefroit is a Belgian paleontologist. He discovered dinosaurs like '' Olorotitan'' in 2003. Godefroit is the director of earth and life sciences This list of life sciences comprises the branches of science that involve the scientific st ...

References

* * Ornithischians Bajocian first appearances Maastrichtian extinctions Taxa named by Paul Sereno {{ornithischian-stub