†Callawayasaurus Carpenter 1999 (elasmosaur)
Vertebrata - Sauropterygia - Elasmosauridae
Full reference: K. Carpenter. 1999. Revision of North American elasmosaurs from the Cretaceous of the Western Interior. Paludicola 2(2):148-173
Parent taxon: Elasmosauridae according to O. Hampe 2013
Sister taxa: Albertonectes, Alexeyisaurus, Alzadasaurinae, Aristonectinae, Callowayosaurus, Cimoliasaurus, Elasmosaurinae, Elasmosaurus, Eromangasaurus, Gronausaurus, Hydralmosaurus, Hydrotherosaurus, Leurospondylus, Libonectes, Mauisaurus, Scanisaurus, Stereosaurus, Styxosaurus, Terminonatator, Thalassiosaurus, Thalassomedon, Thalassonomosaurus, Tuarangisaurus, Wapuskanectes, Zarafasaura, Morturneria
Subtaxa: Callawayasaurus colombiensis
Ecology: aquatic carnivore