Trinacromerum
Trinacromerum is an extinct genus of sauropterygian reptile, a member of the polycotylid plesiosaurs. It contains two species, "T. bentonianum" and "T. kirki". Specimens have been discovered in the Late Cretaceous fossil deposits of what is now modern Kansas and Manitoba. Description. "Trinacromerum" was long. Its teeth show that it fed on small fish. The long flippers of "Trinacromerum" enabled it to achieve high swimming speeds. Its physical appearance was described by Richard Ellis as akin to a "four-flippered penguin." Its name means "three tipped femur". Classification. Below is a cladogram of polycotylid relationships from Ketchum & Benson, 2011