Terminonatator. Danielle Serratos, Druckenmiller, and Benson could not resolve the position of Elasmosaurus in 2017, but they noted that Styxosaurinae would be a synonym of Elasmosaurinae if Elasmosaurus did fall within the group. In 2021 a new topology placed Cardiocorax as a sister taxon of Libonectes, representing an older lineage of elasmosaurids in the Maastrichtian. Topology A: Benson et al. (2013) Topology B: Otero (2016) The family Elasmosauridae was erected by Cope in 1869, and anchored on the genus Elasmosaurus. References External links "Lepidosauromorpha: Elasmosauridae." Palaeos.com Plesiosaurs Cretaceous plesiosaurs Maastrichtian extinctions Prehistoric reptile families