Delphinida

Delphinoidea are the largest group of toothed whales, including 66 genera in 6 families. The largest living member of the superfamily is the orca, which can reach 6 tons, while the smallest is the vaquita.

Lipotidae is a possibly extinct family of river dolphins containing the critically endangered/functionally extinct Chinese river dolphin baiji and the fossil genus Parapontoporia from the Pacific coast of North America during the Late Miocene and Pliocene The genus Prolipotes, which is based on a mandible fragment from Neogene coastal deposits in Guangxi, China, has been classified as an extinct relative of the baiji, but is dubious. The oldest known member of the family is Eolipotes from the Late Miocene of Japan.

Delphinida is a clade of cetaceans in the parvorder Odontoceti, the toothed whales. It includes all modern oceanic dolphins, porpoises, and their relatives, such as Lipotidae and Iniidae. thumb|left|Short-beaked common dolphin (Delphinus delphis)