Cephalorhynchus

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Cephalorhynchus
Temporal range: Holocene
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Commdolph01.jpg
Commerson's dolphin
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Artiodactyla
Infraorder: Cetacea
Family: Delphinidae
Subfamily: Lissodelphininae
Genus: Cephalorhynchus
Gray, 1846
Type species
Delphinus heavisidii [1]
Gray, 1828
Species

C. commersonii
C. eutropia
C. heavisidii
C. hectori

Cephalorhynchus is a genus in the dolphin family Delphinidae.

Extant species

It consists of four species:

ImageScientific nameCommon nameDistribution
Commerson Dolphin closer.jpg Commerson's dolphin C. commersoniiArgentina including Puerto Deseado, in the Strait of Magellan and around Tierra del Fuego, and near the Falkland Islands, near the Kerguelen Islands in the southern part of the Indian Ocean
Black dolphins around isla gordon.jpg Chilean dolphin C. eutropiacoast of Chile
Heaviside-Delphin.jpg Heaviside's dolphin C. heavisidiicoast of northern Namibia at 17°S and as far south as the southern tip of South Africa
Hector'sDolphinsCloudyBay 21Feb2012 AnjanetteBaker.tif Hector's dolphin C. hectoricoastal regions of New Zealand

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 in 2006 indicated the two species traditionally assigned to the genus Lagenorhynchus , the hourglass dolphin 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. [2]

According to a study in 1971, 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. [3]

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<span class="mw-page-title-main">Heaviside's dolphin</span> Species of mammal

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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 moved to other genera. In addition, the extinct species Lagenorhynchus harmatuki is also classified in this genus.

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Sagmatias was a genus of dolphins, defined in 1866 by Edward Drinker Cope with Peale's dolphin as type species, described as Sagmatias amblodon. It has been proposed to resurrect the genus to include four species of oceanic dolphins currently classified in the genus Lagenorhynchus. Mitochondrial DNA studies have indicated that Pacific white-sided dolphin, Peale's dolphin, dusky dolphin and hourglass dolphin are more closely related to dolphins in the Lissodelphininae subfamily, than to the two other members of the genus: Atlantic white-sided dolphin and white-beaked dolphin. This phylogenetic relationship is further supported by cladistic analysis of morphological characters. However, resurrection of the genus Sagmatias has not been accepted by the Society for Marine Mammalogy's taxonomic Committee, because the finer details of the phylogenetic relationships between the four species in the proposed Sagmatias genus and the four species of dolphins in the genus Cephalorhynchus remains to be resolved. Genetic and bioacoustical evidence suggest that Peale's dolphin and hourglass dolphin are closer related to the Cephalorhynchus species than to the Pacific white-sided dolphin and dusky dolphin, which, if true, would make the genus Sagmatias paraphyletic.

<span class="mw-page-title-main">Burrunan dolphin</span> Subspecies of mammal

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References

  1. Wilson, D. E.; Reeder, D. M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. ISBN   978-0-8018-8221-0. OCLC   62265494.
  2. May-Collado, Laura; Agnarsson, Ingi (2006). "Cytochrome b and Bayesian inference of whale phylogeny" (PDF). Molecular Phylogenetics and Evolution. 38 (2): 344–54. Bibcode:2006MolPE..38..344M. doi:10.1016/j.ympev.2005.09.019. ISSN   1055-7903. OCLC   441745572. PMID   16325433 . Retrieved 2 February 2013.
  3. Schevill, W.E.; Watkins, W.A. (15 January 1971). "Pulsed sounds of the porpoise Lagenorhynchus australis". Breviora. 366: 1–10. ISSN   0006-9698. OCLC   80876226.