The Hawaiian blackhead triplefin (''Enneapterygius atriceps''), also known as the Hawaiian triplefin in

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

, is a species of

triplefin Threefin or triplefin blennies are blenny, blenniiforms, small Percomorpha, percomorph marine fish of the family Tripterygiidae. Found in tropical and temperate waters of the Atlantic Ocean, Atlantic, Pacific Ocean, Pacific and Indian Oceans, the ...

blenny in the genus ''

Enneapterygius ''Enneapterygius'' is a genus of fish in the family Tripterygiidae found in the Indian and Pacific Ocean. Species There are currently 63 recognized species in this genus: * '' Enneapterygius abeli'' ( Klausewitz, 1960) (Yellow triplefin) * '' ...

''. It is a

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

blenny found in

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

s in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

, from the

Hawaiian Islands The Hawaiian Islands () are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the Pacific Ocean, North Pacific Ocean, extending some from the Hawaii (island), island of Hawaii in the south to nort ...

French Frigate Shoals The French Frigate Shoals (Hawaiian language, Hawaiian: Kānemilohai) is the largest atoll in the Northwestern Hawaiian Islands, located about northwest of Honolulu, Hawaii, Honolulu. Its name commemorates France, French explorer Jean-Fran ...

Laysan Island Laysan (; ) is one of the Northwestern Hawaiian Islands, located northwest of Honolulu. It has one land mass of , about in size. It is an atoll of sorts, although the land completely surrounds Laysan Lake, some above sea level, that has a sa ...

, and

Midway Atoll Midway Atoll (colloquialism, colloquial: Midway Islands; ; ) is a atoll in the North Pacific Ocean. Midway Atoll is an insular area of the United States and is an Insular area#Unorganized unincorporated territories, unorganized and unincorpo ...

. Blennies in this species swim at a depth range of 1–23 metres, and inhabit dead coral and rock. It was originally described by O.P. Jenkins in 1903, as a species of ''

Tripterygion ''Tripterygion'' is a genus of fish in the family Tripterygiidae, the threefin blennies, the species of which are found in the north eastern Atlantic Ocean, the Mediterranean Sea and the Black Sea. Species * '' Tripterygion delaisi'' Cadenat ...

'', but was reassigned to ''Enneapterygius'' by R. Fricke in 1997.

Description

The Hawaiian blackhead triplefin is considered part of the '' Enneapterygius hemimelas'' species group. It is considered a small or medium member of the group, with males reaching a maximum length of 2.6 centimetres. Males can be distinguished from females by their dark head colouring.

References

External links

''Enneapterygius atriceps''
at www.fishwise.co.za
''Enneapterygius atriceps''
at www.discoverlife.org

at www.marinelifephotography.com
''Enneapterygius atriceps''
at

ITIS The Integrated Taxonomic Information System (ITIS) is an American partnership of federal agencies designed to provide consistent and reliable information on the taxonomy of biological species. ITIS was originally formed in 1996 as an interagenc ...

''Enneapterygius atriceps''
at

World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive catalogue and list of names of marine organisms. Content The content of the registry is edited and maintained by scien ...

Hawaiian blackhead triplefiin Fish described in 1903 Taxa named by Oliver Peebles Jenkins {{Tripterygiidae-stub