Brownsnout spookfish
Brownsnout spookfish | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Argentiniformes |
Family: | Opisthoproctidae |
Genus: | Dolichopteryx |
Species: | D. longipes
|
Binomial name | |
Dolichopteryx longipes (Vaillant, 1888)
| |
Synonyms[2] | |
Aulostoma longipes Vaillant, 1888 |
The brownsnout spookfish or brown-snout spookfish (Dolichopteryx longipes) is a species of
Bahamas, the Greater Antilles, and the Gulf of Mexico, and in the Pacific Ocean it is known from the California Current region and the South China Sea. It is found in the mesopelagic and bathypelagic zones at a depth of 500–2,400 meters (1,600–7,900 ft), but usually occurs below 1,000 meters (3,300 feet). In the Gulf of Mexico it is found shallower, at 310–460 meters (1,020–1,510 ft).[3][6]
Description
The body of D. longipes is slender, the depth 12.6–14.3% of the
gut, a line of chromatophores below the lateral line to the position of dorsal fin, and two blotches on the base of the tail. The snout is dusky in color.[6] The maximum known length is 18 cm (7.1 in).[3]
Biology and ecology
The diet of D. longipes consists primarily of
eggs and larvae. The larvoid juveniles and adults are covered in a gelatinous sheath. Flexion (the curvature of the notochord in the formation of the caudal fin) occurs at around a standard length of 13 mm (0.51 in), and metamorphosis at a standard length of 30 mm (1.2 in). The pectoral and pelvic fins form early, as does the stomach on the left side.[7]
Adult D. longipes exhibit
paedomorphic characteristics found in the juveniles of other opisthoproctids, such as poorly developed muscles (for example the lack of ventral muscles, meaning the gut is enclosed only by the peritoneum and the skin), rudimentary scales and coloration, and the placement of the pectoral and pelvic fins on peduncles that are not connected to the body by muscles. Developed gonads have been observed in a 36 mm (1.4 in) male and a 40 mm (1.6 in) female.[8] Their lifespan is 5 years.[7]
Eyes
D. longipes is unusual in that it uses both
lens to focus its image, as in other fishes. However, inside the diverticulum the light is reflected and focused onto the retina by a curved composite mirror derived from the retinal tapetum, composed of many layers of small reflective plates possibly made of guanine crystals, acting as the reflector equivalent of a Fresnel lens.[9] The split structure of the D. longipes eye allows the fish to see both up and down at the same time. In addition, the mirror system is superior to a lens in gathering light. It is likely that the main eye serves to detect objects silhouetted against the sunlight, while the diverticulum serves to detect bioluminescent flashes from the sides and below.[4]
References
- ^ a b Knudsen, S. (2015). "Dolichopteryx longipes". . Retrieved 12 June 2022.
- ^ a b Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Dolichopteryx longipes". Catalog of Fishes. California Academy of Sciences. Retrieved 12 June 2022.
- ^ a b c d Froese, Rainer; Pauly, Daniel (eds.) (2022). "Dolichopteryx longipes" in FishBase. February 2022 version.
- ^ a b c
Wagner, H.J.; Douglas, R.H.; Frank, T.M.; Roberts, N.W.; Partridge, J.C. (27 January 2009). "A novel vertebrate eye using both refractive and reflective optics". PMID 19110427.
- ^ a b Smith, L. (8 January 2009). "Fish with four eyes can see through the deep sea gloom". Times Online. London, UK: Times Newspapers. Retrieved 14 March 2009.
- ^ a b c
McEachran, J.D. & Fechhelm, J.D. (1998). Fishes of the Gulf of Mexico: Myxiniformes to Gasterosteiformes. University of Texas Press. ISBN 0-292-75206-7.
- ^ a b
"Brownsnout spookfish" (PDF). Ichthyoplankton Information System. Alaska Fisheries Science Center. National Oceanographic and Atmospheric Administration. July 2008. Retrieved 14 March 2009.
- ^
Cohen, D.M. (29 June 1960). "New records of the opisthoproctid genus Bathylychnops, with a notice of neoteny in the related genus Dolichopteryx". JSTOR 1440218.
- ^ Wallace, John (20 March 2014). "Double-duty deep sea fish eye has one mirrored and one refractive lens system". Optics. Laser Focus World.