Distribution
Cusk-eels live in temperate and tropical oceans throughout the world. They live close to the sea bottom, ranging from shallow water to the hadal zone. One species, '' Abyssobrotula galatheae'', was recorded at the bottom of the Puerto Rico Trench, making it the deepest recorded fish at .Ecology
Cusk-eels are generally very solitary in nature, but some species have been seen to associate themselves with tube worm communities. Liking to be hidden when they are not foraging, they generally associate themselves within muddy bottoms, sinkholes, or larger structures that they can hide in or around, such as caves, coral crevices, or communities of bottom-dwelling invertebrates, with some parasitic species of cusk-eel actually living inside of invertebrate hosts, such as oysters, clams and sea cucumbers. Cusk-eels generally feed nocturnally, preying on invertebrates, crustaceans and other small bottom-dwelling fishes.Phylogeny
Due to the inconsistencies in specific morphological characteristics in closely related species, attempts to use different characteristics, such as the position of pelvic fins, to classify Ophiididae into distinct families have proven highly unsatisfactory. Overall, Ophidiidae are classified based on whether or not they practice viviparity and the structures they contain that are associated with bearing life.Characteristics
Cusk-eels are characterized by a long, slender body that is about 12–13 times as long as it is deep. The largest species, '' Lamprogrammus shcherbachevi'', grows up to in length, but most species are shorter than . Their dorsal and anal fins are typically continuous with the caudal fin (with exception to a few species), forming a long, ribbon like fin around the posterior of the cusk-eel's body. This caudal fin will often be seen to be reduced to a fleshy or bony point, especially when confluent with the dorsal and anal fins. The dorsal fin to anal fin ray ratio is approximately 1.5:1, leading to the dorsal fin typically being longer than the anal. The pectoral fins of cusk-eels are typically longer than the length of their head. Unlike true eels of the order Anguilliformes, cusk-eels have ventral fins that are developed into a forked barbel-like organ below the mouth. In true eels by contrast, the ventral fins are never well-developed and usually missing entirely. Cusk-eels have large mouths relative to their heads, with the upper jaw reaching beyond the eye, and paired nostrils on either side of the head. In cusk-eels, scales are potentially absent; when present, they are small.Reproduction
Unlike their close relatives, the viviparous brotulas of the family Bythitidae, cusk-eel species are egg-bearing, orConservation status
While a few species are fished commercially – most notably the pink cusk-eel, ''Genypterus blacodes'' – and several species of the order Ophidiiformes are listed as vulnerable, not enough information has been gathered about Ophidiidae as a whole to determine their conservation status.Genera
The cusk-eel family contains about 240 species, grouped into 50 genera: * Genus †'' Ampheristus'' Subfamily Brotulotaenilinae * Genus '' Brotulotaenia'' Subfamily Neobythitinae * Genus '' Abyssobrotula'' * Genus '' Alcockia'' * Genus '' Apagesoma'' * Genus '' Barathrites'' * Genus '' Barathrodemus'' * Genus '' Bassogigas'' * Genus '' Bassozetus'' * Genus '' Bathyonus'' * Genus '' Benthocometes'' * Genus '' Dannevigia'' – Australian tusk * Genus '' Dicrolene'' * Genus '' Enchelybrotula'' * Genus '' Epetriodus'' – needletooth cusk * Genus '' Eretmichthys'' * Genus '' Glyptophidium'' * Genus '' Holcomycteronus'' * Genus '' Homostolus'' – filament cusk * Genus '' Hoplobrotula'' * Genus '' Hypopleuron'' – whiptail cusk * Genus '' Lamprogrammus'' * Genus '' Leptobrotula'' * Genus '' Leucicorus'' * Genus '' Luciobrotula'' * Genus '' Mastigopterus'' * Genus '' Monomitopus'' * Genus '' Neobythites'' * Genus '' Neobythitoides'' * Genus '' Penopus'' * Genus '' Petrotyx'' * Genus '' Porogadus'' * Genus '' Pycnocraspedum'' * Genus '' Selachophidium'' – Gunther's cusk-eel * Genus '' Sirembo'' * Genus '' Spectrunculus'' * Genus '' Spottobrotula'' * Genus '' Tauredophidium'' * Genus '' Tenuicephalus'' * Genus '' Typhlonus'' * Genus '' Ventichthys'' – East-Pacific ventbrotula * Genus '' Xyelacyba'' Subfamily Ophidiinae * Genus '' Cherublemma'' – black brotula * Genus '' Chilara'' – spotted cusk-eel * Genus '' Genypterus'' * Genus '' Lepophidium'' * Genus '' Menziesichthys'' * Genus '' Ophidion'' * Genus '' Otophidium'' * Genus '' Parophidion'' * Genus '' Raneya'' – banded cusk-eelGallery
References
{{Authority control Taxa named by Constantine Samuel Rafinesque Extant Maastrichtian first appearances