- Art Gallery -

Steno bredanensis

Steno bredanensis, Photo: Michael Lahanas

Cladus: Eukaryota
Supergroup: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Mammalia
Subclassis: Theria
Infraclassis: Placentalia
Superordo: Cetartiodactyla
Ordo: Cetacea
Subordo: Odontoceti
Infraordines: Delphinida
Superfamilia: Delphinoidea
Familia: Delphinidae
Genus: Steno
Species: Steno bredanensis

References

* Steno bredanensis on Mammal Species of the World.
* Mammal Species of the World: A Taxonomic and Geographic Reference, 2 Volume Set edited by Don E. Wilson, DeeAnn M. Reeder
* 180415 Delphinidae Report on ITIS

Vernacular names
Internationalization
日本語: シワハイルカ
Türkçe: Pürüzlü dişli yunus

------------

The Rough-toothed Dolphin (Steno bredanensis) is a fairly large dolphin that can be found in deep warm and tropical waters around the world.
Naming and discovery

The species was first described by Georges Cuvier in 1823. The genus name Steno, of which this species is the only member, comes from the Greek for 'narrow', referring to the animal's beak - which is a diagnostic characteristic of the species. The specific name honours van Breda, who studied Cuvier's writings. The common name refers to the thin lines of enamel that run vertically down the dolphin's teeth.

Physical description

The characteristic feature of this dolphin is its conical head and slender nose. The flippers are set back further along the body than in other similar dolphins (at sea this dolphin may be confused with the Spinner, Spotted and Bottlenose Dolphins.) The dorsal fin is pronounced.

The lips, throat and belly are pinkish-white. The flanks are a light grey and the back and dorsal fin a much darker grey. The dolphin grows up to about 2.5m in length and weighs about 150kg.

The species is social. Group sizes are commonly as large as fifty and groups as large as 100 have been reported. The dolphin has not been observed to bow-ride but does "skim" - swim with their heads and chin above the surface of the water.

Population and distribution

The distribution and population of the Rough-toothed Dolphin is poorly understood. Most of the research activity concerning the dolphin has been directed in the eastern Pacific Ocean where a population estimate of 150,000 has been obtained. There have been numerous reports from other warm seas, usually as a result of by-catches. Populations of unknown sizes exist in the Mediterranean and Caribbean Seas and the Atlantic, Indian. Live sightings are almost universally made far off-shore beyond the continental shelf.

Conservation

The population is not believed to be threatened by human activities. A small number of individuals have been harpooned by Japanese whalers. Others have been caught in seine nets by trawlers fishing for tuna.

Captivity

Rough-toothed dolphins adapt well to captivity and have proven to be intelligent and creative. Less than a dozen Rough-toothed dolphins live in various dolphinariums around the world.

References

* Hammond, P.S., Bearzi, G., Bjørge, A., Forney, K., Karczmarski, L., Kasuya, T., Perrin, W.F., Scott, M.D., Wang, J.Y., Wells, R.S. & Wilson, B. (2008). Steno bredanensis. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 26 February 2009. Database entry includes justification for why this species is listed as data deficient
* Steno bredanensis pp. 269-280, by J Maigret in Handbuch der Säugetiere Europas. Band 6: Meeressäuger Teil 1A: Wale und Delphine 1 Niethammer J, Krapp F, (Eds.) (1995).

Biology Encyclopedia

Mammals Images

Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License