Xinpusaurus: Difference between revisions

'''''Xinpusaurus''''' is an extinct [[genus]] of [[thalattosaur]] from the [[Late Triassic]] of [[Guanling]] in [[Guizhou, China]]. Several species have been named since 2000: the [[type species]] ''X. suni'' along with the species ''X. bamaolinensis'' and ''X. kohi''. A 2013 study proposed that all three species are [[synonym (taxonomy)|synonymous]] with each other, in which case ''X. suni'' would be the only valid species, although a 2014 study argued that ''X. kohi'' was also valid.<ref name=LJ13>{{cite journal |last=Liu |first=J. |year=2013 |title=On the taxonomy of ''Xinpusaurus'' (Reptilia: Thalattosauria) |journal=Vertebrata PalAsiatica |volume=51 |issue=1 |pages=17–23 |url=http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/201301/P020130131404692609056.pdf}}</ref><ref name=":0">{{Cite journal|url=http://www.palaeodiversity.org/pdf/07/04Palaeodiversity_7-14_Maisch_3.pdf|title=On the morphology and taxonomic status of ''Xinpusaurus kohi'' JIANG et al., 2004 (Diapsida: Thalattosauria) from the Upper Triassic of China|last1 = Maisch | first1 = M.W. | journal = Palaeodiversity | volume = 7 | pages = 47–59 | date = 2014}}</ref> A fourth species, ''X. xingyiensis'', was described in 2016.<ref name=":1">{{Cite journal |last1=Li |first1=Z.-G. |last2=Jiang |first2=D.-Y. |last3=Rieppel |first3=O. |last4=Motani |first4=R. |last5=Tintori |first5=A. |last6=Sun |first6=Z.-Y. |last7=Ji |first7=C. |date=2016-11-01 |title=A new species of Xinpusaurus (Reptilia, Thalattosauria) from the Ladinian (Middle Triassic) of Xingyi, Guizhou, southwestern China |url=https://www.researchgate.net/publication/309411833 |journal=Journal of Vertebrate Paleontology |volume=36 |issue=6 |pages=e1218340 |doi=10.1080/02724634.2016.1218340 |bibcode=2016JVPal..36E8340L |issn=0272-4634 |s2cid=132418823}}</ref>

''Xinpusaurus'' is a thalattosaur, a group of triassic marine reptiles with long, paddle-like tails and short legs with independently movable digits. Specifically, it is a member of the group thalattosauroidea, which are characterized by their downturned [[premaxilla]]e. ''Xinpusaurus'' had a short neck, a massive [[Quadrate bone|quadrate]], and one of the few braincases preserved in thalattosaurs. The lower jaws of this genus show two different forms of [[dentary]]-[[Suprangular|surangular]] sutures, either a v-shaped suture with the surangular cutting into the dentary from the side (type 1) or an oblique suture with the surangular underlying the dentary (type 2). ''X. bamaolinensis'' preserves a type 2 suture while ''X. kohi'' has a type 1 suture. ''X. suni''<nowiki/>'s suture differs between specimens while ''X. xingyiensis'' seems to have a type 2 suture.<ref name="LJ13" /> The dentary is also narrow and shorter than the snout, with robust, pointed teeth in the front of its jaws and broad crushing teeth in the back of its jaws, suggesting that it fed on hard-shelled prey, although these adaptations are not as extreme as those of ''[[Concavispina]]'', which had exclusively short and blunt teeth.<ref name="LZLH13">{{Cite journal|last1=Liu|first1=J.|last2=Zhao|first2=L. J.|last3=Li|first3=C.|last4=He|first4=T.|year=2013|title=Osteology of ''Concavispina biseridens'' (Reptilia, Thalattosauria) from the Xiaowa Formation (Carnian), Guanling, Guizhou, China|journal=Journal of Paleontology|volume=87|issue=2|pages=341|doi=10.1666/12-059R1.1|bibcode=2013JPal...87..341L |s2cid=83684967}}</ref> This genus also has a uniquely upward-curving [[maxilla]], a wide proximal end of the [[humerus]], and a [[Radius (bone)|radius]] with a convex lateral edge and concave medial edge.<ref name=":1" />

{{EureptiliaThalattosauria|N.}}