†unranked clade Elasmosaurinae
Reptilia - Plesiosauria - Elasmosauridae
Synonym: Styxosaurinae Otero 2016
Parent taxon: Euelasmosaurida according to J. P. O'Gorman 2019
See also Otero 2016, Serratos et al. 2017 and Welles 1962
Sister taxa: Libonectes, Thalassomedon
Subtaxa: Albertonectes Elasmosaurus Hydrotherosaurus Nakonanectes Styxosaurus Terminonatator
Distribution:
• Cretaceous of Canada (2: Alberta, Saskatchewan collections), Japan (7), United States (12: California, Kansas, Montana, Nebraska, South Dakota, Wyoming)
Total: 21 collections each including a single occurrence