Sphenotitan

{{Short description|Extinct genus of reptiles}}

{{Automatic taxobox

| fossil_range = Late Triassic {{fossilrange|Norian}}

| image = Sphenotitan skull.svg

| image_upright = 1.25

| image_caption = Skull diagram

| taxon = Sphenotitan

| authority = Martínez et al., 2013

| type_species = {{extinct}}Sphenotitan leyesi

| type_species_authority = Martínez et al., 2013

}}

Sphenotitan is an extinct genus of rhynchocephalian reptile, known from the Late Triassic (Norian) Quebrada del Barro Formation of Argentina.{{Cite journal | last1 = Martinez | first1 = R. N. | last2 = Apaldetti | first2 = C. | last3 = Colombi | first3 = C. E. | last4 = Praderio | first4 = A. | last5 = Fernandez | first5 = E. | last6 = Malnis | first6 = P. S. | last7 = Correa | first7 = G. A. | last8 = Abelin | first8 = D. | last9 = Alcober | first9 = O. | doi = 10.1098/rspb.2013.2057 | title = A new sphenodontian (Lepidosauria: Rhynchocephalia) from the Late Triassic of Argentina and the early origin of the herbivore opisthodontians | journal = Proceedings of the Royal Society B: Biological Sciences | volume = 280 | issue = 1772 | pages = 20132057 | year = 2013 | pmid = 24132307| pmc = 3813332}} It is the earliest known member of the herbivorous Elienodontinae, and the only one known from the Triassic.{{Cite journal |last1=Simões |first1=Tiago R. |last2=Kinney-Broderick |first2=Grace |last3=Pierce |first3=Stephanie E. |date=2022-03-03 |title=An exceptionally preserved Sphenodon-like sphenodontian reveals deep time conservation of the tuatara skeleton and ontogeny |journal=Communications Biology |language=en |volume=5 |issue=1 |page=195 |doi=10.1038/s42003-022-03144-y |issn=2399-3642 |pmc=8894340 |pmid=35241764}} It was a large-sized sphenodontian, with an estimated skull length of over {{Convert|10|cm|in}}. The skull is roughly triangular in shape, and had large upper temporal fenestrae. The region of the skull in front of the eye socket (preoribital region) is short. The premaxillae form a beak, with a cutting edge similar to a chisel. The teeth of Sphenotitan, like other elienodontines, were large and wide, and designed for shredding vegetation, with blade-like palatal teeth on the roof of the mouth.