''Cephalorhynchus'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

in the

dolphin A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Delphinidae Oceanic dolphins or Delphinidae are a widely distributed family of dolphins that live in the sea. Close to forty extant species are recognised. They include several big species whose common names contain "whale" rather than "dolphin", such as the ...

Extant species

It consists of four species: The species have similar physical features—they are small, generally playful, blunt-nosed dolphins—but they are found in distinct geographical locations. A phylogenetic analysis by indicated the two species traditionally assigned to the genus ''

Lagenorhynchus ''Lagenorhynchus'' is a genus of oceanic dolphins in the infraorder Cetacea, presently containing six extant species. However, there is consistent molecular evidence that the genus is polyphyletic and several of the species are likely to be move ...

'', the

hourglass dolphin The hourglass dolphin (''Lagenorhynchus cruciger'') is a small dolphin in the family Delphinidae that inhabits offshore Antarctic and sub-Antarctic waters. It is commonly seen from ships crossing the Drake Passage, but has a circumpolar dis ...

''L. cruciger'' and Peale's dolphin ''L. australis'' are actually phylogenetically nested among the species of ''Cephalorhynchus'', and they suggest these two species should be transferred to the genus ''Cephalorhynchus''. Some acoustic and morphological data support this arrangement, at least with respect to Peale's dolphin. According to , Peale's dolphin and the ''Cephalorhynchus'' species are the only dolphins that do not whistle (no acoustic data are available for the hourglass dolphin). Peale's dolphin also shares with several ''Cephalorhynchus'' species the possession of a distinct white "armpit" marking behind the pectoral fin.

References

* * Oceanic dolphins Cetacean genera Animals that use echolocation Taxa named by John Edward Gray {{whale-stub