Abyssosaurus

Abyssosaurus is a derived cryptoclidid plesiosaur from the Upper Hauterivian (Lower Cretaceous) of the Menya River, Chuvashia, Russia. It was named and described in 2011 by Alexander Yu Berezin (Berezin 2011). A partial skull associated with the holotype specimen (MChEIO, no. PM/1) was not described in the original 2011 paper but was discovered later in …