Morphology of Western Pond Turtle (Actinemys), Blanding’s Turtle (Emydoidea), and European Pond Turtle (Emys). These far-flung species are still sometimes considered members of the genus Emys, however molecular phylogeny has cast doubt on whether or not they form a real group and morphology has shown several significant differences. Emydoidea has the most pronounced differences, including elongate neck vertebrae, an elongate skull and large thoracic rib heads.
Fritz, U. et al. (2011) Competing generic concepts for Blanding’s, Pacific and European pond turtles (Emydoidea, Actinemys and Emys)—Which is best?. Zootaxa 2791 41–53