Rileyasuchus

Taxobox
name = "Rileyasuchus"
fossil_range = Late Triassic


image_width =
regnum = Animalia
phylum = Chordata
classis = Sauropsida
infraclassis = Archosauromorpha
unranked_ordo = Crurotarsi
ordo = Phytosauria
genus = "Rileyasuchus"
genus authority = Kuhn, 1961
subdivision_ranks=Species
subdivision= *"R. bristolensis" (von Huene, 1902 [originally "Rileyia"] ) (type)

"Rileyasuchus" (meaning "Riley’s crocodile") is a genus of phytosaur from the Rhaetian (Late Triassic) of England. It has a confusing history, being associated with the taxonomy of "Palaeosaurus" and "Thecodontosaurus", and being a replacement name for a preoccupied genus ("Rileya", which had already been used by Howard (or Ashmead; it's unclear which one has priority, but they apparently are the same animal) in 1888 for a hymenopteran).Howard, L.O. (1888). The chalcid genus "Rileya". Canadian Entomology 20:191-195.] Ashmead, W.H. (1888). A revised generic table of the Euryrtominae, with descriptions of new species. Pt I. Entomol. Am. 4:41-43.]

History and Taxonomy

Friedrich von Huene named the new genus for two vertebrae and a humerus from deposits in Bristol.von Huene, F. (1902). Überischt über die Reptilien der Trias. "Geologische und Paläontologie Abhandlungen, Neu Folge" 8:97-156. [German] ] He had recognized it as a phytosaur by 1908 (by which point a few "Palaeosaurus" species had been added to the genus).von Huene, F. (1908). On phytosaurian remains from the Magnesian Conglomerate of Bristol ("Rileya platyodon"). "Annals and Magazine of Natural History", series 8 1:228-230.]

It seems to have sat unrecognized for most of the 20th century, except for 1961 when Oskar Kuhn renamed it from "Rileya" to "Rileyasuchus".Kuhn, O. (1961). "Die Familien der rezenten und fossilen Amphibien und Reptilien." Meisenbach:Bamberg, 79 p. ] Adrian Hunt in 1994 (doctoral dissertation) first suggested that it was a herrerasaurid, although this was never published.Hunt, A.P. (1994). Unpublished doctoral dissertation, [http://dml.cmnh.org/2000Feb/msg00297.html discussed here] ] Benton "et al." (2000) indicated that the type specimen was actually a chimera composed of a phytosaur humerus and "Thecodontosaurus" vertebrae.Benton, M.J, Juul, L., Storrs, G.W., and Galton, P.M. (2000). Anatomy and systematics of the prosauropod dinosaur "Thecodontosaurus antiquus" from the upper Triassic of southwest England. "Journal of Vertebrate Paleontology" 20(1):77-108.] It is best regarded as a "nomen dubium".

Paleobiology

As a phytosaur, it would have been a semi-aquatic crocodile-like predator.

References

External links

* [http://dml.cmnh.org/2000Feb/msg00297.html "Rileyasuchus" as herrerasaurid]