{{Short description|Extinct genus of reptiles}} {{Automatic taxobox | fossil_range = Late Triassic<br />~{{Fossil range|235.0|221.5}} | image = Miodentosaurus BW.jpg | image_caption = Life restoration | taxon = Miodentosaurus | authority = Cheng ''et al.'', 2007 | type_species = '''''Miodentosaurus brevis''''' | type_species_authority = Cheng ''et al.'', 2007 }}
'''''Miodentosaurus''''' is a genus of thalattosaurian (a type of extinct marine reptile) from the Late Triassic of China. It is one of several thalattosaurs found in the Xiaowa Formation, also known as the Wayao Member of the Falang Formation. The genus name "''Miodentosaurus''" translates to "Few toothed-lizard" while the species name "''brevis''" means "short", in reference to its short snout.<ref name=":0">{{Cite journal|last1=Cheng|first1=Yen-Nien|last2=Wu|first2=Xiao-Chun|last3=Sato|first3=Tamaki|date=2007|title=A new Thalattosaurian (Reptilia: Diapsida) From the Upper Triassic of Guizhou, China|url=https://www.researchgate.net/publication/311584721|journal=Vertebrata PalAsiatica|volume=45|issue=3|pages=246–260}}</ref>
== Description == ''Miodentosaurus'' is a thalattosaur, a group of marine reptiles with long, paddle-like tails and short legs with independently movable digits. It was a large member of the group, with a complete specimen measuring {{convert|4.4|m|ft}} long.<ref name=":2"/> ''Miodentosaurus'' is specifically an Askeptosauroid, a specific group of thalattosaurs with rather straight snouts. Despite being closely related to ''Askeptosaurus'' (a thalattosaur with a very long and toothy snout), ''Miodentosaurus'' had a quite short snout (shorter than the rest of the head) with only a few conical teeth on the premaxillae and dentaries. Although this snout configuration is not known in any other thalattosaurians, ''Miodentosaurus'' does share a number of other features with Askeptosauroids, such as having 10 neck vertebrae and a large pineal foramen.<ref name=":1">{{Cite journal|last1=Wu|first1=Xiao-Chun|last2=Cheng|first2=Yen-Nien|last3=Sato|first3=Tamaki|last4=Shan|first4=Hsi-Yin|date=2009|title=''Miodentosaurus brevis'' Cheng et al. 2007 (Diapsida: Thalattosauria): Its postcranial skeleton and phylogenetic relationships|url=https://www.researchgate.net/publication/272822304|journal=Vertebrata PalAsiatica|volume=47|issue=1|pages=1–20}}</ref>
Apart from its unique cranial features, ''Miodentosaurus'' also has characteristically flat front claws and the two specimens known were both more than four meters long, making it one of the largest thalattosaurs known.<ref name=":2">{{Cite journal|last1=Zhao|first1=Li-Jun|last2=Sato|first2=Tamaki|last3=Liu|first3=Jun|last4=Li|first4=Chun|last5=Wu|first5=Xiao-Chun|date=2010|title=A new skeleton of ''Miodentosaurus brevis'' (Diapsida: Thallatosauria) with a further study of the taxon|url=http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/201002/P020100202389848150350.pdf|journal=Vertebrata PalAsiatica|volume=48|issue=1|pages=1–10}}</ref>
== History and specimens == The holotype of ''Miodentosaurus brevis'', NMNS 004727 / F003960, is a well-preserved and fairly complete articulated skeleton. It was discovered in the Carnian-age Xiaowa Formation (or Wayao Member of the Falang Formation) of China, where other thalattosaurs as ''Anshunsaurus huangguoshuensis'' and ''Concavispina biseridens'' were found. The skull and mandibles were the first elements described in 2007,<ref name=":0" /> while the postcranial skeleton was described in 2009.<ref name=":1" />
An even more complete specimen, ZMNH M8742, was described in 2010. This specimen is one of the most complete thalattosaur skeletons known and also depicts pelvic, metatarsal, and coracoid features different from those of the holotype, showing instances of individual variation within the genus.<ref name=":2" />
A 2023 study by Chai ''et al''. suggested that ''Miodentosaurus'' may actually represent the same animal as the contemporary ''Wayaosaurus'', which was named in 2007, based on similarities in the skull, dorsal vertebrae, and pubis. This would render ''Miodentosaurus'' a subjective junior synonym of that genus. They also speculated that it is possible the two represent distinct species within the same genus.<ref name=Wayaosaurus2023>{{Cite journal |last1=Chai |first1=Jun |last2=Lu |first2=Hao |last3=Jiang |first3=Da-Yong |last4=Motani |first4=Ryosuke |last5=Druckenmiller |first5=Patrick S. |last6=Tintori |first6=Andrea |last7=Kelley |first7=Neil P. |date=2023-10-23 |title=Reidentification of ''Wayaosaurus bellus'' and the conservative trunk and tail shape of Thalattosauria |journal=Historical Biology |language=en |pages=1–20 |doi=10.1080/08912963.2023.2264886 |s2cid=264474151 |issn=0891-2963|url=https://figshare.com/articles/journal_contribution/24425832 |url-access=subscription }}</ref>
== References == {{Portal|Paleontology}} {{Reflist}}
{{Thalattosauria|N.}} {{Taxonbar|from=Q1014885}}
Category:Thalattosauria Category:Late Triassic reptiles of Asia Category:Triassic China Category:Fossils of China Category:Fossil taxa described in 2007 Category:Prehistoric reptile genera