''Tricuspisaurus'' is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

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 ...

of reptile originally described as a trilophosaurid; 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, Antarc ...

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

Glamorgan , HQ = Cardiff , Government = Glamorgan County Council (1889–1974) , Origin= , Code = GLA , CodeName = Chapman code , Replace = * West Glamorgan * Mid Glamorgan * South Glamorgan , Motto ...

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 (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ...

British fissure deposits. 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 Greek, meaning 'different teeth') is an animal which possesses more than a single tooth morphology. In vertebrates, heterodont pertains to animals where teeth are differentiated into different forms. For example, ...

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 , lord_ ...

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 ...

. 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 Paul E. Olsen (born August 4, 1953) is an American paleontologist and author and co-author of a large number of technical papers. Growing up as a teenager in Livingston, New Jersey, he was instrumental in Riker Hill Fossil Site being named a Na ...

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