''Tricuspisaurus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

of reptile originally described as a

trilophosaurid Trilophosaurs are lizard-like Triassic allokotosaur reptiles related to the archosaurs. The best known genus is '' Trilophosaurus'', a herbivore up to long. It had a short, unusually heavily built skull, equipped with massive, broad flattened c ...

; it was later considered likely to be a

procolophonid Procolophonidae is an extinct family of small, lizard-like parareptiles known from the Late Permian to Late Triassic that were distributed across Pangaea, having been reported from Europe, North America, China, South Africa, South America, Antar ...

, but recent analyses have affirmed the original classification. Fossils are known from the

Ruthin Quarry Ruthin ( ; cy, Rhuthun) is a market town and community in Denbighshire, Wales, in the south of the Vale of Clwyd. It is Denbighshire's county town. The town, castle and St Peter's Square lie on a hill, skirted by villages such as Pwllglas ...

in Glamorgan,

Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...

, one of several

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 ...

Early Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma ...

British fissure deposits British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories, and Crown Dependencies. ** Britishness, the British identity and common culture * British English ...

. Like some trilophosaurs, it has an

edentulous Toothlessness, or edentulism, is the condition of having no teeth. In organisms that naturally have teeth, it is the result of tooth loss. Organisms that never possessed teeth can also be described as edentulous. Examples are the members of the ...

, or toothless beak. ''Tricuspisaurus'' gets its name from its

heterodont In anatomy, a heterodont (from Ancient Greek, Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology (biology), morphology. In vertebrates, heterodont pertains to animals where teeth are differentiate ...

dentition, which includes ''tricuspid'' teeth, or teeth with three cusps. The

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

, ''T. thomasi'', was named in 1957 along with the possible trilophosaur '' Variodens inopinatus'' from

Somerset ( en, All The People of Somerset) , locator_map = , coordinates = , region = South West England , established_date = Ancient , established_by = , preceded_by = , origin = , lord_lieutenant_office =Lord Lieutenant of Somerset , lor ...

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 ...

. Although originally classified as a trilophosaur, ''Tricuspisaurus'' was reclassified as a procolophonid in 1993 by paleontologists

Hans-Dieter Sues Hans-Dieter Sues (born January 13, 1956) is a German-born American paleontologist who is Senior Scientist and Curator of Vertebrate Paleontology at the National Museum of Natural History of the Smithsonian Institution in Washington, DC. He receiv ...

and Paul E. Olsen. This was due to similarities between its tricuspid teeth and those of the newly described procolophonid '' Xenodiphyodon''. Along with ''Tricuspisaurus'', ''Variodens'' and ''

Trilophosaurus jacobsi ''Trilophosaurus'' (Greek language, Greek for "lizard with three ridges") is a lizard-like trilophosaurid allokotosaur known from the Late Triassic of North America. It was a herbivore up to 2.5 m long. It had a short, unusually heavily built sku ...

'' were also considered to be procolophonids. More recently described cranial material from ''T. jacobsi'' indicates that it is still likely to be a trilophosaur.

References

Allokotosaurs Late Triassic reptiles of Europe Prehistoric reptile genera {{triassic-reptile-stub