Family LINOPHRYNIDAE


Common name: Netdevils, Headlight Anglerfishes, Leftvent Anglerfishes, Leftvent Seadevils, Sinistral Seadevils

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Summary:

A spectacular and diverse group of deepsea anglerfishes (Suborder Ceratioidei) with marked sexual dimorphism and sexual parasitism. 

The larger females are short and rounded, with huge heads, short snouts, enormous mouths full of long dagger-like teeth and a spine above each eye.

The conspicuous lure or esca on the snout harbours symbiotic bacteria that are bioluminescent. 

Most species also have an elaborate bioluminescent chin barbel, with the anglerfish producing the luminescence, rahter than bioluminescent bacteria within the barbel. 

Linophrynids also have few dorsal and anal fin rays, and the anus is positioned to the left of the ventral midline of the body.  

The tiny slender males have large telescopic eyes, large nasal organs and denticular teeth. Males are obligate sexual parasites on the larger females.


Cite this page as:
Dianne J. Bray, Leftvent anglerfishes, LINOPHRYNIDAE in Fishes of Australia, accessed 21 Feb 2019, http://fishesofaustralia.net.au/Home/family/195

More Info


Family Taxonomy

Family with 5 genera and 27 species. The genera Borophryne, Haplophryne and Photocorynus are each contain only a single species. the genus Acentrophryne contains 2 species, while the large genus Linophryne contains 22 species. Haplophryne with a single species, and Linophryne with two species are known from Australian waters.

Family Distribution

Linophrynids are found worldwide in all oceans, inhabiting meso- and bathypelagic depths from 100-2000 m

Family Description

Meristic features: Dorsal fin II, 3-4 (rarely 4), Anal fin 2-4 (rarely 2 or 4); Pectoral fin 13-19; Caudal fin 9; Branchiostegal rays 5 (rarely 4) 

Females - Body short, deep, globular to oval in shape; head large, sphenotic head spines well-developed, eye small, nostrils on papillae; mouth very large,  oblique to almost horizontal, extending to rear end of eye or beyond; jaw teeth highly variable, some species with extremely long dagger-like teeth, vomer with fang-like teeth in some. 

Soft dorsal and anal fins far back on body; pelvic fins absent. Illicium short, with a prominent bioluminescent esca; 2 genera have an elaborate hyoid barbel with many light organs. 

Skin completely naked, dermal spinules absent; anus directed to the left side of the body. 

Males - both free living and parasitic males are known for most genera. Free-living males have prominent tubular eyes; large forward-directed olfactory organs with well-separated anterior nostrils; short, stout denticular bones with 3-7 teeth dorsally, 2-13 teeth ventrally. Skin naked, dermal spinules absent  

Family Size

Females reach 27.5 cm; tiny males grow to 29 mm.

Family Colour

Females of most species are overall dark brown to black, except for parts of the esca, the fins and the chin barbel in the genus Linophryne. The Soft Leafvent Angler Haplophryne mollis is unpigmented. The tiny free-living males of Linophryne are dark, while those of other genera are unpigmented. Parasitic males of Haplophryne and Photocorynus are unpigmented, while those of other genera are dark.

Family Feeding

Carnivores. Females attract prey with their bioluminescent lure and elaborate bioluminescent chin barbel (if present). Linophrynids reportedly feed on fishes and crustaceans.

Family Reproduction

Adult female linophrynids have two different bioluminescent systems. The dorsal lure or esca harbours bioluminescent bacteria that emit the light. The light emitted by the chin barbel, however, is intrinsic bioluminescence produced by the anglerfish. 

Reproduction is oviparous, with pelagic eggs and larvae. Larvae are relatively long and slender, with inflated skin, small pectoral fins and lack pelvic fins. They aresexually dimorphic, and female larvae possess a rudimentary illicium and a hyoid barbel rudiment (in 2 genera) by about 10 mm SL. 

Larvae undergo a prolonged development and metamorphose between 15 and 32 mm SL. 
Male linophrynids are thought to be obligate parasites.

Family Commercial

Although of no commercial importance, deep-sea anglerfishes are taken as incidental bycatch in commercial trawls..

Family Conservation

IUCN Red List: Not evaluated.

Family Remarks

As with most deepsea anglerfishes, the females are poor swimmers. The tiny males, however actively seek a mate using their well-developed olfactory organs. Males attach and hold onto females using specialized toothy denticles on the tips of their jaws. Their tissue and presumably blood vessels fuse with that of the female and they become parasites.

Family Biology


Author

Dianne J. Bray

References


Bertelsen, E. 1951. The ceratioid fishes. Ontogeny, taxonomy, distribution and biology. Dana Rept. 39, 276 pp.

Bertelsen, E. 1980. Notes on Linophrynidae V: A revision of the deepsea anglerfishes of the Linophryne arborifer-group (Pisces, Ceratioidei). Steenstrupia 6(6): 29-70.

Bertelsen, E. 1982. Notes on Linophrynidae VIII: A review of the genus Linophryne, with new records and descriptions of two new species. Steenstrupia 8(3): 49-104.

Bertelsen, E. 1984. Ceratioidei: Development and relationships. pp. 325-334, In Moser, H.G., W.J. Richards, D.M. Cohen, M.P. Fahay, A.W. Kendall, Jr. & S.L. Richardson (eds). Ontogeny and Systematics of Fishes. Spec. Publ. No. 1, Amer. Soc. Ichthy. Herpet., ix + 760 pp.

Hansen, K. & P. J. Herring. 1977. Dual bioluminescent systems in the anglerfish genus Linophryne (Pisces: Ceratioidea). J. Zool. London 182: 103-124.

Herring, P. J. & O. Munk. 1994. The escal light gland of the deep-sea anglerfish Haplophryne mollis (Pisces: Ceratioidei), with observations on luminescence control. J. Mar. Biol. Assn. U.K. 74: 747-763.

Pietsch, T.W. 1999. Linophrynidae. Netdevils (deepsea anglerfishes), p. 2037, In Carpenter, K.E. & V.H. Niem. Species identification guide for fisheries purposes. The living marine resources of the western central Pacific. Batoid fishes, chimeras and bony fishes. Part 1 (Elopidae to Linophrynidae). FAO, Rome.

Pietsch, T.W. 2005. Dimorphism, parasitism, and sex revisited: modes of reproduction among deep-sea ceratioid anglerfishes (Teleostei: Lophiiformes). Ichthyol. Res. 52: 207-236.

Pietsch, T.W. 2009. Oceanic Anglerfishes: Extraordinary Diversity in the Deep Sea. University of California press, 576 pp.

Pietsch, T.W. & Kenaley, C.P. 2005. Linophrynidae. Leftvent Seadevils. Version 06 November 2005. http://tolweb.org/Linophrynidae/22027/2005.11.06 in The Tree of Life Web Project, http://tolweb.org/

Widder, E.A. 2010. Bioluminescence in the Ocean: Origins of Biological, Chemical, and Ecological Diversity. Science 7: 704-708.