{"id":20838,"date":"2023-06-07T13:24:57","date_gmt":"2023-06-07T05:24:57","guid":{"rendered":"https:\/\/chinosaur.com\/?p=20838"},"modified":"2023-06-07T13:24:57","modified_gmt":"2023-06-07T05:24:57","slug":"the-definition-of-dinosaurs","status":"publish","type":"post","link":"https:\/\/chinosaur.com\/index.php\/2023\/06\/07\/the-definition-of-dinosaurs\/","title":{"rendered":"The definition of dinosaurs"},"content":{"rendered":"

Under\u00a0phylogenetic nomenclature<\/a>, dinosaurs are usually defined as the group consisting of the\u00a0most recent common ancestor<\/a>\u00a0(MRCA) of\u00a0Triceratops<\/a><\/i>\u00a0and\u00a0modern birds<\/a>\u00a0(Neornithes), and all its descendants.[10]<\/a><\/sup>\u00a0It has also been suggested that Dinosauria be defined with respect to the MRCA of\u00a0Megalosaurus<\/a><\/i>\u00a0and\u00a0Iguanodon<\/a><\/i>, because these were two of the three genera cited by\u00a0Richard Owen<\/a>\u00a0when he recognized the Dinosauria.[11]<\/a><\/sup>\u00a0Both definitions result in the same set of animals being defined as dinosaurs: “Dinosauria =\u00a0Ornithischia<\/a>\u00a0+\u00a0Saurischia<\/a>“. This definition includes major groups such as\u00a0ankylosaurians<\/a>\u00a0(armored herbivorous quadrupeds),\u00a0stegosaurians<\/a>\u00a0(plated herbivorous quadrupeds),\u00a0ceratopsians<\/a>\u00a0(bipedal or quadrupedal herbivores with\u00a0neck frills<\/a>),\u00a0pachycephalosaurians<\/a>\u00a0(bipedal herbivores with thick skulls),\u00a0ornithopods<\/a>\u00a0(bipedal or quadrupedal herbivores including “duck-bills<\/a>“),\u00a0theropods<\/a>\u00a0(mostly bipedal carnivores and birds), and\u00a0sauropodomorphs<\/a>\u00a0(mostly large herbivorous quadrupeds with long necks and tails).[12]<\/a><\/sup><\/p>\n

Birds are the sole surviving dinosaurs. In traditional\u00a0taxonomy<\/a>, birds were considered a separate\u00a0class<\/a>\u00a0that had evolved from dinosaurs, a distinct\u00a0superorder<\/a>. However, a majority of contemporary paleontologists concerned with dinosaurs reject the traditional style of classification in favor of\u00a0phylogenetic<\/a>\u00a0taxonomy; this approach requires that, for a group to be natural, all descendants of members of the group must be included in the group.[13]<\/a><\/sup>\u00a0Birds belong to the dinosaur subgroup\u00a0Maniraptora<\/a>, which are\u00a0coelurosaurs<\/a>, which are theropods, which are saurischians.[14]<\/a><\/sup><\/p>\n

Research by Matthew G. Baron,\u00a0David B. Norman<\/a>, and Paul M. Barrett in 2017 suggested a radical revision of dinosaurian systematics. Phylogenetic analysis by Baron\u00a0et al.<\/i>\u00a0recovered the Ornithischia as being closer to the Theropoda than the Sauropodomorpha, as opposed to the traditional union of theropods with sauropodomorphs. This would cause sauropods and kin to fall outside traditional dinosaurs, so they re-defined Dinosauria as the last common ancestor of\u00a0Triceratops horridus<\/i>,\u00a0Passer domesticus<\/a><\/i>\u00a0and\u00a0Diplodocus carnegii<\/a><\/i>, and all of its descendants, to ensure that sauropods and kin remain included as dinosaurs. They also resurrected the clade\u00a0Ornithoscelida<\/a>\u00a0to refer to the group containing Ornithischia and Theropoda.[15]<\/a><\/sup>[16]<\/a><\/sup><\/p>\n","protected":false},"excerpt":{"rendered":"

Under\u00a0phylogenetic nomenclature, dinosaurs are usually defined as the group consisting of the\u00a0most recent common ancestor\u00a0(MRCA) of\u00a0Triceratops\u00a0and\u00a0modern birds\u00a0(Neornithes), and all its […]<\/p>\n","protected":false},"author":1,"featured_media":20839,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-20838","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"_links":{"self":[{"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/posts\/20838","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/comments?post=20838"}],"version-history":[{"count":1,"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/posts\/20838\/revisions"}],"predecessor-version":[{"id":20840,"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/posts\/20838\/revisions\/20840"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/media\/20839"}],"wp:attachment":[{"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/media?parent=20838"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/categories?post=20838"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chinosaur.com\/index.php\/wp-json\/wp\/v2\/tags?post=20838"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}