''Rileyasuchus'' is a

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 ...

phytosaur Phytosaurs (Φυτόσαυροι in greek) are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs belong to the order Phytosauria. Phytosauria and Phytosauridae are often considered to be equivalent ...

from the

Rhaetian The Rhaetian is the latest age of the Triassic Period (in geochronology) or the uppermost stage of the Triassic System (in chronostratigraphy). It was preceded by the Norian and succeeded by the Hettangian (the lowermost stage or earliest age ...

(

Late Triassic The Late Triassic is the third and final epoch (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch ...

)

Magnesian Conglomerate The Magnesian Conglomerate is a geological formation in Clifton, Bristol in England (originally Avon), Gloucestershire and southern Wales, present in Tytherington, Durdham Down and Cromhall Quarry. It dates back to the Rhaetian stage of the Late ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

. It has a confusing history, being associated with the taxonomy of ''

Palaeosaurus ''Palaeosaurus'' (or ''Paleosaurus'') is a genus of indeterminate archosaur known from two teeth found in the Bromsgrove Sandstone Formation and also either the Magnesian Conglomerate or the Avon Fissure Fill of Clifton, Bristol, England (orig ...

'' and ''

Thecodontosaurus ''Thecodontosaurus'' ("socket-tooth lizard") is a genus of herbivorous basal sauropodomorph dinosaur that lived during the late Triassic period (Rhaetian age). Its remains are known mostly from Triassic "fissure fillings" in South England. ''The ...

'', and being a replacement name for a preoccupied genus (''

Rileya ''Rileya'' is a genus of parasitoid hymenopteran named and described in 1888. It belongs to the Eurytomidae.Riley, C.V.; Ashmead, W.H.; Howard, L.O. (1894) Report upon the parasitic Hymenoptera of the island of St. Vincent., JOURBOOK: Journal of ...

'', which had already been used by Ashmead, and Howard both in 1888 for a

hymenopteran Hymenoptera is a large order (biology), order of insects, comprising the sawfly, sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are Par ...

).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 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 ...

named the new genus for two

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

e and a

humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a roun ...

from deposits in

Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...

.von Huene, F. (1902). Überischt über die Reptilien der Trias. ''Geologische und Paläontologie Abhandlungen, Neu Folge'' 8:97-156.

erman Erman Rašiti may refer to: Given name * Erman Bulucu (born 1989), Turkish footballer * Erman Eltemur (born 1993), Turkish karateka * Erman Güraçar (born 1974), Turkish footballer * Erman Kılıç (born 1983), Turkish footballer * Erman Kunter (b ...

/ref> 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 Oskar Kuhn (7 March 1908, Munich – 1990) was a German palaeontologist. Life and career Kuhn was educated in Dinkelsbühl and Bamberg and then studied natural science, specialising in geology and paleontology, at the University of Munich, fr ...

renamed it from ''Rileya'' to ''Rileyasuchus''.Kuhn, O. (1961). ''Die Familien der rezenten und fossilen Amphibien und Reptilien.'' Meisenbach:Bamberg, 79 p.

Adrian Hunt Adrian is a form of the Latin given name Adrianus or Hadrianus. Its ultimate origin is most likely via the former river Adria from the Venetic and Illyrian word ''adur'', meaning "sea" or "water". The Adria was until the 8th century BC the main ...

in 1994 (doctoral dissertation) first suggested that it was a

herrerasaurid Herrerasauridae is a family of carnivorous dinosaurs, possibly basal to either theropods or even all of saurischians, or even their own branching from dracohors, separate from dinosauria altogether. They are among the oldest known dinosaurs, fi ...

, although this was never published.Hunt, A.P. (1994). Unpublished doctoral dissertation
discussed here
/ref> Benton ''et al.'' (2000) indicated that the

type specimen In biology, a type is a particular wiktionary:en:specimen, specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to a ...

was actually a

chimera Chimera, Chimaera, or Chimaira (Greek for " she-goat") originally referred to: * Chimera (mythology), a fire-breathing monster of Ancient Lycia said to combine parts from multiple animals * Mount Chimaera, a fire-spewing region of Lycia or Cilicia ...

composed of a phytosaur humerus and ''

'' 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 In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

''.

Paleobiology

As a phytosaur, it would have been a semi- aquatic

crocodile Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...

-like

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

References

External links

''Rileyasuchus'' as herrerasaurid
{{Taxonbar, from=Q15378969 Phytosaurs Late Triassic reptiles of Europe Taxa named by Oskar Kuhn Prehistoric reptile genera