 A 2009 study by Druckenmiller and Russel recovered "Umoonasaurus" as a pliosauroid and a possible member of Polycotylidae.In 2010, Ketchum and Benson found "Umoonasaurus" to be a member of Leptocleididae, although finding that family to belong to Plesiosauroidea instead of Pliosauroidea.