Reptilia - Plesiosauria - Elasmosauridae
Parent taxon: Elasmosauridae according to S. P. Welles 1962
Sister taxa: Alexeyisaurus, Alzadasaurus kansasensis, Alzadasaurus tropicus, Callawayasaurus, Callowayosaurus, Cardiocorax, Chubutinectes, Cimoliasaurus, Cimoliasaurus andium, Cimoliasaurus cantabrigiensis, Cimoliasaurus caudalis, Elasmosaurus amalitskii, Elasmosaurus kurskensis, Elasmosaurus orskensis, Elasmosaurus serdobensis, Elasmosaurus sternbergi, Eromangasaurus, Euelasmosaurida, Fluvionectes, Fresnosaurus, Gronausaurus, Jucha, Lagenanectes, Leivanectes, Leurospondylus, Mauisaurus gardneri, Plesiosaurus constrictus, Plesiosaurus crassicostatus, Plesiosaurus gulo, Plesiosaurus gurgitis, Plesiosaurus helmersenii, Plesiosaurus holmesii, Plesiosaurus hoodii, Plesiosaurus mackayii, Plesiosaurus mauritanicus, Plesiosaurus sutherlandi, Pliosaurus gigas, Pliosaurus macrospondylus, Scanisaurus, Stereosaurus, Thalassiosaurus, Thalassiosaurus ischiadicus, Thalassonomosaurus, Thalassonomosaurus nobilis, Wapuskanectes, Weddellonectia, Woolungasaurus, Woolungasaurus glendowerensis, Zarafasaura, Brimosaurus
Subtaxa: Alzadasaurus Ogmodirus
Type: Alzadasaurus
Ecology: aquatic carnivore
Distribution:
• Cretaceous of Canada (1: Northwest Territories collection), United States (2: Kansas, Montana)
Total: 3 collections each including a single occurrence