Selmasaurus

Selmasaurus Temporal range: Late Cretaceous, Santonian 86.3–83.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Selmasaurus johnsoni mounted skull in the Rocky Mountain Dinosaur Resource Center in Woodland Park, Colorado.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Clade:	†Mosasauria
Family:	†Mosasauridae
Clade:	†Russellosaurina
Clade:	†Selmasaurini
Genus:	†Selmasaurus Wright & Shannon, 1988
Species
†S. russelli Wright & Shannon, 1988 (type) †S. johnsoni Polcyn & Everhart, 2008

Selmasaurus is an extinct genus of marine lizard belonging to the mosasaur family. It is classified as part of the Plioplatecarpinae subfamily alongside genera like Angolasaurus and Platecarpus. Two species are known, S. russelli and S. johnsoni; both are exclusively known from Santonian deposits in the United States.

Selmasaurus is unique among the mosasaurs in that its skull is unusually akinetic, meaning that it is incapable of widening to swallow larger prey. Most mosasaurs have skulls which possess "coupled kinesis" (mesokinesis and streptostyly), that is, parts of the jaw can open widely to accommodate large prey.