Luskhan

Luskhan (meaning "water spirit chief") is an extinct genus of large pliosaurid plesiosaurs from the Lower Cretaceous of western Russia. The only known species is L. itilensis, first described in 2017 from a well-preserved and nearly complete skeleton discovered in the Ulyanovsk region. As an early-diverging brachauchenine, Luskhan consequently exhibits an intermediate combination of traits seen in more basal (less specialized) and more derived (more specialized) pliosaurs. However, Luskhan departs significantly from other pliosaurs in that it exhibits a lack of adaptations in its skull to feeding on large prey; its slender snout, small teeth, and short tooth rows instead indicate a skull adapted for feeding on small, soft prey. With these features, it is the pliosaur that approaches closest to the distantly-related piscivorous polycotylids, having convergently evolved these traits more than 10 million years apart.

==Discovery and naming== thumb|left|Holotype skull The holotype and only known specimen of Luskhan consists of an almost complete, three-dimensionally preserved pliosaur skeleton, discovered in 2002 by Russian paleontologist Gleb N. Uspensky on the eastern bank of the Volga River, about north of the village of Slantsevy Rudnik in the Ulyanovsk region of western Russia. Deposits in the region consist of dark grey and slightly sandy shale layers and siltite layers, in which carbonate nodules are embedded. The fossil skeleton was found in the g-5 horizon (layer). After its discovery, the specimen was stored in the I.A. Goncharov Ulyanovsk Regional Museum of Local Lore (YKM), under the specimen number YKM 68344/1_262.