''Picrodon'' is the name given to a genus of

archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...

, possibly a

sauropodomorph Sauropodomorpha ( ; from Greek, meaning "lizard-footed forms") is an extinct clade of long-necked, herbivorous, saurischian dinosaurs that includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had lo ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

, 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 ...

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 ...

which was possibly synonymous with the dubious archosaur '' Avalonianus''. The type, and only species, ''P. herveyi'', was named in 1898.H. G. Seeley. 1898. On large terrestrial saurians from the Rhaetic Beds of Wedmore Hill, described as '' Avalonia sanfordi'' and ''Picrodon herveyi''. Geological Magazine, decade 4 5:1-6

Discovery and naming

In 1894, W. A. Sanford described the fossil remains of what he considered to be two large

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

s discovered near

Westbury-on-Severn Westbury-on-Severn is a rural village in England that is the centre of the large, rural parish, also called Westbury-on-Severn. Location The village is situated on the A48 road (between Minsterworth and Newnham on Severn) and bounded by the R ...

Glastonbury Glastonbury ( , ) is a town and civil parish in Somerset, England, situated at a dry point on the low-lying Somerset Levels, south of Bristol. The town had a population of 8,932 in the 2011 census. Glastonbury is less than across the River ...

(

Westbury Formation The Westbury Formation is a geological Formation (geology), formation in England, one of the Penarth Group. It dates back to the Rhaetian.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Triassic, Europe)." In: Weishampel, David B. ...

) by Eev. Sydenham H. A. Hervey and Sanford himself.''Proceedings of the Somerset Archaeological Society'' - vol. xl, 1894, p. 234

Harry Govier Seeley Harry Govier Seeley (18 February 1839 – 8 January 1909) was a British paleontologist. Early life Seeley was born in London on 18 February 1839, the second son of Richard Hovill Seeley, a goldsmith, and his second wife Mary Govier. When his fa ...

described the fossils and named two genera: ''

Avalonia Avalonia was a microcontinent in the Paleozoic era. Crustal fragments of this former microcontinent are terranes in parts of the eastern coast of North America: Atlantic Canada, and parts of the East Coast of the United States, East Coast of the ...

'' (preoccupied; now '' Avalonianus'') and ''Picrodon''; both are based solely on teeth. Only a single

tooth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...

, holotype BMNH R2875, belonging to ''P. herveyi'' is known, making the remains insufficient to make judgments on its diet or its classification; although it is agreed that ''Picrodon'' was an archosaur to some degree.

Classification

Sanford (1894) classified ''Picrodon'' as a

, while Seeley (1898) classified ''Picrodon'' as a

saurian Sauria is the clade of diapsids containing the most recent common ancestor of Archosauria (which includes crocodilians and birds) and Lepidosauria (which includes squamates and the tuatara), and all its descendants. Since most molecular phyl ...

. More modern research however almost certainly places ''Picrodon'' within Archosauria;

Peter Malcolm Galton Peter Malcolm Galton (born 14 March 1942 in London) is a British vertebrate paleontologist who has to date written or co-written about 190 papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosau ...

(1985) suggested that ''Picrodon'' may have been a basal sauropodomorph. Currently, its exact phylogenetic placement within Archosauria remains unknown.

References

Archosaurs Triassic archosaurs Fossil taxa described in 1898 {{paleo-archosaur-stub es:Picrodon fr:Picrodon it:Picrodon solus