Rileyasuchus Explained

Rileyasuchus is a genus of phytosaur from the Rhaetian (Late Triassic) Magnesian Conglomerate 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 Ashmead, and Howard both in 1888 for a hymenopteran).^{[1] [2]}

History and taxonomy

Friedrich von Huene named the new genus for two vertebrae and a humerus from deposits in Bristol.^[3] He had recognized it as a phytosaur by 1908 (by which point a few Palaeosaurus species had been added to the genus).^[4]

It seems to have sat unrecognized for most of the 20th century, except for 1961 when Oskar Kuhn renamed it from Rileya to Rileyasuchus.^[5] Adrian Hunt in 1994 (doctoral dissertation) first suggested that it was a herrerasaurid, although this was never published.^[6] Benton et al. (2000) indicated that the type specimen was actually a chimera composed of a phytosaur humerus and Thecodontosaurus vertebrae.^[7] It is best regarded as a nomen dubium.

Paleobiology

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

External links

• Rileyasuchus as herrerasaurid

Notes and References

1. Howard, L.O. (1888). The chalcid genus Rileya. Canadian Entomology 20:191-195.
2. Ashmead, W.H. (1888). A revised generic table of the Euryrtominae, with descriptions of new species. Pt I. Entomol. Am. 4:41-43.
3. von Huene, F. (1902). Überischt über die Reptilien der Trias. Geologische und Paläontologie Abhandlungen, Neu Folge 8:97-156. [German]
4. 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.
5. Kuhn, O. (1961). Die Familien der rezenten und fossilen Amphibien und Reptilien. Meisenbach:Bamberg, 79 p.
6. Hunt, A.P. (1994). Unpublished doctoral dissertation, discussed here
7. 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.