''Rachitrema'' is a poorly known

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

of ichthyosaur from the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

. Its remains were found in France by two independent collectors, towards the end of the nineteenth century. They were only isolated bone fragments.

Classification

The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

is ''R. pellati'', described by Sauvage in 1883. When first described, Sauvage classified it as a

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 ...

.H.-E. Sauvage. 1883. Recherches sur les reptiles trouvés dans l'étage rhétien des environs d'Autun esearch on the reptiles found in the Rhaetian stage of the environs of Autun Annales des Sciences Géologiques 14(3):1-44 Later,

Franz Nopcsa Franz may refer to: People * Franz (given name) * Franz (surname) Places * Franz (crater), a lunar crater * Franz, Ontario, a railway junction and unorganized town in Canada * Franz Lake, in the state of Washington, United States – see ...

referred the genus to

Anchisauridae ''Anchisaurus'' is a genus of basal sauropodomorph dinosaur. It lived during the Early Jurassic Period, and its fossils have been found in the red sandstone of the Portland Formation, Northeastern United States, which was deposited from the He ...

, while

Karl Alfred von Zittel Karl Alfred Ritter von Zittel (25 September 1839 – 5 January 1904) was a German palaeontologist best known for his ''Handbuch der Palaeontologie'' (1876–1880). Biography Karl Alfred von Zittel was born in Bahlingen in the Grand Duchy o ...

referred it to either Zanclodontidae or Megalosauridae. The ichthyosaur nature of ''Rachitrema'' was recognized by

Friedrich von Huene Friedrich von Huene, born Friedrich Richard von Hoinigen, (March 22, 1875 – April 4, 1969) was a German paleontologist who renamed more dinosaurs in the early 20th century than anyone else in Europe. He also made key contributions about v ...

, who synonymized it with '' Shastasaurus''. Sauvage conceded that ''Rachitrema'' was non-dinosaurian, and the ichthyosaur classification of the genus became universally accepted by several authors. McGowan and Motani (2003) considered ''Rachitrema'' dinosaurian without comment. However, recent re-examination of the type material of ''Rachitrema'' reaffirms the ichthyosaurian classification of the genus, with most of the original remains referable to Ichthyosauria, and the rest being indeterminate beyond Reptilia.

References

External links

Dinosaur Mailing List entry, which discusses the genus
Nomina dubia Fossils of France Fossil taxa described in 1883 {{triassic-reptile-stub