Mikko's Phylogeny Archive Front page   Taxonomic history of the genus Styxosaurus Welles, 1943

After O'Keefe, 2001

    †Styxosaurus Welles, 1943
        †Alzadasaurus
        †Thalassiosaurus
        †Thalassonomosaurus

    †Styxosaurus snowii (Williston, 1890) Welles, 1943
        †Alzadasaurus kansasensis
        †Alzadasaurus pembertoni
        †Thalassiosaurus ischiadicus
        †Thalassonomosaurus marshi

    †Styxosaurus browni Welles, 1952
        [is now jr. synon. of †Hydralmosaurus serpentinus (Cope, 1877) Welles, 1943 sensu O'Keefe, 2001]
        [Treated as a valid species of genus Styxosaurus by Sato, 2003]

Reference(s):

O'Keefe, F. R., 2001: A cladistic analysis and taxonomic revision of the Plesiosauria (Reptilia: Sauropterygia).
–Acta Zoologica Fennica: Vol. #213, pp. 1-63

Sato, T., 2003: Terminonatator ponteixensis, a new elasmosaur (Reptilia: Sauropterygia) from the Upper Cretaceous of Saskatchewan.
–Journal of Vertebrate Paleontology: Vol. 23, #1, pp. 89-103