Is the taxon rank of XXX species or genus?
Aristonectes
Aristonectes has been recently placed within its own family, along with Tatenectes, Kaiwhekea, and Kimmerosaurus, by O'Keefe and Street (2009), as sister family of the polycotylid cryptoclidoids, but an even more recent study (Otero et al., 2014) has shown Aristonectes to be a derived Elasmosaurid, thus making Aristonectidae synonymous with Elasmosauridae.