Cetaceans and Hippopotamuses

Whippomorpha is the clade containing the Cetacea (whales, dolphins, etc.) and their closest living relatives, the hippopotamuses, named by Waddell et al. (1999). It is defined as a crown group, including all species that are descendants of the most recent common ancestor of Hippopotamus amphibius and Tursiops truncatus. This would be a subgrouping of the Cetartiodactyla (which also includes pigs and ruminants). How recently whales and hippos share a common ancestor is unclear, though the genetic