''Rileyasuchus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

phytosaur Phytosaurs (Φυτόσαυροι in Greek, meaning 'plant lizard') are an extinct group of large, mostly semiaquatic Late Triassic archosauriform or basal archosaurian reptiles. Phytosaurs belong to the order Phytosauria and are sometimes ref ...

from the

Rhaetian The Rhaetian is the latest age (geology), age of the Triassic period (geology), Period (in geochronology) or the uppermost stage (stratigraphy), stage of the Triassic system (stratigraphy), System (in chronostratigraphy). It was preceded by the N ...

(

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 a ...

) Magnesian Conglomerate of

England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...

. 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 (or ...

'' and ''

Thecodontosaurus ''Thecodontosaurus'' ("socket-tooth lizard") is a genus of herbivorous basal sauropodomorph dinosaur that lived during the late Triassic period (Carnian? age). Its remains are known mostly from Triassic "fissure fillings" in South England. ''T ...

'', 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 Hymenoptera is a large order of insects, comprising the 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 parasitic. Females typi ...

).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

In 1902, Friedrich von Huene named the new genus for two

vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...

e and a

humerus The humerus (; : humeri) 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 (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

from deposits in

Bristol Bristol () is a City status in the United Kingdom, cathedral city, unitary authority area and ceremonial county in South West England, the most populous city in the region. Built around the River Avon, Bristol, River Avon, it is bordered by t ...

.von Huene, F. (1902). Überischt über die Reptilien der Trias. ''Geologische und Paläontologie Abhandlungen, Neu Folge'' 8:97-156. erman/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 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
discussed here
/ref> Benton ''et al.'' (2000) indicated that the

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

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 ...

''. ''Rileya'' was named after

palaeontologist Paleontology, also spelled as palaeontology or palæontology, is the scientific study of the life of the past, mainly but not exclusively through the study of fossils. Paleontologists use fossils as a means to classify organisms, measure geolo ...

and

surgeon In medicine, a surgeon is a medical doctor who performs surgery. Even though there are different traditions in different times and places, a modern surgeon is a licensed physician and received the same medical training as physicians before spec ...

Henry Riley who helped to discover the first known fossils in

in 1834.

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 more loosely to include ...

-like

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

References

External links

''Rileyasuchus'' as herrerasaurid
{{Taxonbar, from=Q15378969 Phytosauria Late Triassic reptiles of Europe Taxa named by Oskar Kuhn Prehistoric reptile genera Fossil taxa described in 1961