What is "hydralmosaurus"

Hydralmosaurus (meaning "salt water lizard") is a genus of elasmosaurid plesiosaur. It is known only from a single specimen discovered in Late Cretaceous (late Santonian - early Campanian age) rocks of Nebraska, USA. Hydralmosaurus was coined as a new genus for " Elasmosaurus" serpentinus in 1943 by Samuel Paul Welles. A 2016 study found it to be synonymous with Styxosaurus.