page_title: Palaeosaurus
section_title: Nineteenth century
hierarchical_section_title: Palaeosaurus / History and classification / Nineteenth century
caption_attribution_description: A picture from the first issue of "Il Politecnico" by Carlo Cattaneo (1839)
context_page_description: Palaeosaurus is a genus of indeterminate archosaur known from two teeth found in either the Magnesian Conglomerate or the Avon Fissure Fill of Clifton, Bristol, England. It has had a convoluted taxonomic history.
  Richard Owen's mistake of associating prosauropod skeletal remains with the carnivorous teeth which Riley and Stutchbury called Palaeosaurus, combined with von Huene's Teratosaurus minor, which was also a combination of carnivore and prosauropod remains, led paleontologists to view prosauropods as carnivorous animals for quite a long time. This error made it into several textbooks and other dinosaur reference works.
context_section_description: In 1836, two British scientists, Henry Riley and Samuel Stutchbury, briefly and informally published on two new fossil teeth found in or near the city of Bristol, England, which they called Palaeosaurus cylindrodon and Palaeosaurus platyodon. Riley and Stutchbury did not mean to assign these species to Saint-Hilaire's genus of teleosaurids; they simply did not know the name had been used. Thecodontosaurus was also named in this publication. Only in 1840 do Riley and Stutchbury fully describe their two species of Palaeosaurus, each based on a single sharp tooth from the Late Triassic Period. The spellings were then corrected to read Paleosaurus cylindrodon and Paleosaurus platyodon.
  In 1842, Sir Richard Owen created the name Dinosauria. In the same publication, he attempted to redescribe Riley and Stutchbury's Paleosaurus and Thecodontosaurus, which he did not consider to be dinosaurs. Not knowing of the change in spelling, he changed the name back to Palaeosaurus, and this spelling was followed by all subsequent authors until 1959. Owen assigns other bones to Palaeosaurus, which would later be re-classified to the prosauropod dinosaur Thecodontosaurus. Contrary to Owen, in 1870, Thomas Henry Huxley described both Thecodontosaurus and Palaeosaurus as dinosaurs for the first time. He considered Palaeosaurus platyodon to be synonymous with Thecodontosaurus antiquus, most likely due to the Thecodontosaurus bones that Owen assigned to the former genus. However, Huxley regarded P. cylindrodon as an unrelated carnivorous theropod.
  American paleontologist Edward Drinker Cope named a third species, Palaeosaurus fraserianus, in 1878, for an isolated tooth found in Triassic rocks in Pennsylvania. Today these are regarded as those of a sauropodomorph. In 1881, a fourth species is created, Palaeosaurus stricklandi; these are now recognized to be those of a phytosaur.
caption: The earliest drawing captioned Palaeosaurus (incorrectly captioned as Paleosaurus)- although this now lost fossil was probably not a Palaeosaurus (drawn in 1839 by Carlo Cattaneo for the first issue of "Il Politecnico")
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