Systematics and phylogeny of Stegosauria (Dinosauria: Ornithischia).

SYNOPSISStegosauria is a clade of ornithischian dinosaurs characterised by a bizarre array of dermal armour extending, in two parasagittal rows, from the cervical region to the end of the tail. Although Stegosaurusis one of the most familiar of all dinosaurs, little is known regarding the evolutionary history of this clade.Alpha-level taxonomic revision of all proposed stegosaur taxa shows that 11 species of stegosaur can be regarded as valid on the basis of autapomorphies. These are: Dacentrurus armatusand Loricatosaurus priscus(gen. nov.) from Europe; Kentrosaurus aethiopicusand Paranthodon africanusfrom Africa; Tuojiangosaurus multispinus, Chungkingosaurus jiangbeiensis, Huayangosaurus taibaii, Gigantspinosaurus sichuanensisand Stegosaurus homheni(comb. nov.) from China; and Stegosaurus mjosi(comb. nov.) and Stegosaurus armatusfrom North America.A cladistic analysis of Stegosauria (the first to be based upon direct observation of all relevant specimens) is presented, which indicates that Tuojiangosaurus, Loricatosaurusand Paranthodonare sister taxa to Stegosaurus. Stegosaurinae can be defined as all stegosaurs more closely related to Stegosaurusthan to Dacentrurus; Stegosauridae is defined as all stegosaurs more closely related to Stegosaurusthan to Huayangosaurus; and Huayangosauridae can be defined as all stegosaurs more closely related to Huayangosaurusthan to Stegosaurus. This study is also the first phylogenetic analysis to include Gigantspinosaurus, which is recovered as the most basal stegosaur. [ABSTRACT FROM AUTHOR]