''Monognathus'', or onejaw, is the only genus of the family Monognathidae of deep-sea eels. The name comes from the Greek ''monos'' meaning “one” and ''gnathos'' meaning “jaw”, a reference to the large mouth in comparison with the rest of the fish, and also the absence of an upper jaw ( maxilla and premaxilla bones are absent).

Description

The dorsal and

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

s lack bony supports and the pectoral fins are missing. The snout has a fang connected to glands, which are venomous in adults. These eels are virtually blind, with rudimentary eyes and small olfactory organs, although the male olfactory organs are enlarged, perhaps suggesting a method of "sniffing out" a mate. Typical lengths are from 4 to 10 cm (1.5–4 in), the maximum length recorded is 15.9 cm (6.3 in).

Distribution

They are found at depths of over 2,000 m (6,600 ft), and are found in all oceans.

Species

The fifteen known species are: * ''

Monognathus ahlstromi ''Monognathus ahlstromi'', the paddletail onejaw, is an ocean-dwelling eel found in the North Pacific Ocean off of the coast of the United States. It is found up to a depth of 2,000 m.

'' Raju, 1974 (Paddletail onejaw) * '' Monognathus berteli'' J. G. Nielsen & Hartel, 1996. * '' Monognathus bertini'' Bertelsen & J. G. Nielsen, 1987. * ''

Monognathus boehlkei ''Monognathus boehlkei'' is a deep-sea eel inhabiting all oceans at depths up to 2,000 meters. Little is known of this species. Description The species is characterized by a distinctive high number of anal fin rays and a short, blunt head with ...

'' Bertelsen & J. G. Nielsen, 1987. * '' Monognathus bruuni''

Bertin Bertin ( la, Bertinus; 615 – ''c''. 709 AD), also known as Saint Bertin the Great, was the Franks, Frankish abbot of a monastery in Saint-Omer later named the Abbey of Saint Bertin after him. He is venerated as a saint by the Catholic and Ort ...

, 1936. * '' Monognathus herringi'' Bertelsen & J. G. Nielsen, 1987. * '' Monognathus isaacsi'' Raju, 1974. * ''

Monognathus jesperseni ''Monognathus'', or onejaw, is the only genus of the family Monognathidae of deep-sea eels. The name comes from the Greek ''monos'' meaning “one” and ''gnathos'' meaning “jaw”, a reference to the large mouth in comparison with the rest o ...

, 1936. * ''

Monognathus jesse ''Monognathus'', or onejaw, is the only genus of the family Monognathidae of deep-sea eels. The name comes from the Greek ''monos'' meaning “one” and ''gnathos'' meaning “jaw”, a reference to the large mouth in comparison with the rest o ...

'' Raju, 1974. * '' Monognathus nigeli'' Bertelsen & J. G. Nielsen, 1987. * '' Monognathus ozawai'' Bertelsen & J. G. Nielsen, 1987. * '' Monognathus rajui'' Bertelsen & J. G. Nielsen, 1987. * ''

Monognathus rosenblatti ''Monognathus'', or onejaw, is the only genus of the family Monognathidae of deep-sea eels. The name comes from the Greek ''monos'' meaning “one” and ''gnathos'' meaning “jaw”, a reference to the large mouth in comparison with the res ...

'' Bertelsen & J. G. Nielsen, 1987. * ''

Monognathus smithi ''Monognathus'', or onejaw, is the only genus of the family Monognathidae of deep-sea eels. The name comes from the Greek ''monos'' meaning “one” and ''gnathos'' meaning “jaw”, a reference to the large mouth in comparison with the res ...

'' Bertelsen & J. G. Nielsen, 1987. * ''

Monognathus taningi ''Monognathus'', or onejaw, is the only genus of the family Monognathidae of deep-sea eels. The name comes from the Greek ''monos'' meaning “one” and ''gnathos'' meaning “jaw”, a reference to the large mouth in comparison with the res ...

, 1936.

References

Monognathidae Deep sea fish Marine fish genera Taxa named by Léon Bertin {{Saccopharyngiformes-stub