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Black seadevils | |
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Humpback anglerfish, Melanocetus johnsonii | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Lophiiformes |
Suborder: | Ceratioidei |
Family: | Melanocetidae T. N. Gill, 1879 |
Genus: | Melanocetus Günther, 1864 |
Type species | |
Melanocetus johnsonii Günther, 1864 | |
Species | |
See text. |
Black seadevils are small, deepsea lophiiform fishes of the family Melanocetidae. The five known species (with only two given common names) are all within the genus Melanocetus. They are found in tropical to temperate waters of the Atlantic, Indian, and Pacific Oceans, with one species known only from the Ross Sea.
One of several anglerfish families, black seadevils are named for their intimidating appearance and typically pitch black skin. The humpback anglerfish (Melanocetus johnsonii) was featured on the August 14, 1995, issue of Time magazine, [1] becoming a flagship species for deep sea fauna.
The black seadevil family, Melanocetidae, was first proposed as a subfamily in 1878 by the American biologist Theodore Gill. [2] The only genus in the family is Melanocetus which was proposed as a monospecific genus in 1864 by the German-born British herpetologist and ichthyologist Albert Günther when he described the humpback anglerfish (M. johnsoni). [3] The type locality of M. johnsoni was give as off Madeira. [4] The 5th edition of Fishes of the World classifies the family Melanocetidae in the suborder Ceratioidei of the anglerfish order Lophiiformes. [5]
The black seadevil family, Melanocetidae and the genus name Melanocetus are a combination of melanos meaning "black" and cetus, which means a "large sea creature", typically used to refer to whales. [6] Günther did not explain this choice of name but did note the unform black colour, including the inside of the mouth of M. johnsoni. [7]
The black seadevil family, Melanocetidae, contains the single genus Melanocetus which has six valid species classified within it: [8]
Black seadevils are characterised by a gelatinous, mostly scaleless, globose body, a large head, and generous complement of menacingly large, sharp, glassy, fang-like teeth lining the jaws of a cavernous, oblique mouth. These teeth are depressible and present only in females. Some species have a scattering of epidermal spinules on the body, and the scales (when present) are conical, hollow, and translucent. Like other anglerfishes, black seadevils possess an illicium and esca; the former being a modified dorsal spine —the "fishing rod"—and the latter being the bulbous, bioluminescent "fishing lure". The esca is simple in black seadevils (with either a conical terminus or anterior and posterior ridges in some species), and both it and the illicium are free of denticles.
The bioluminescence is produced by symbiotic bacteria; these bacteria are thought to enter the esca via an external duct (in at least two species, the esca is not luminous until this duct develops, suggesting the bacteria originate from the surrounding seawater). The bacteria, belonging to the family Vibrionaceae, are apparently different in each anglerfish species; the bacteria have yet to be cultured in vitro .
The eyes of black seadevils are small; the pupil is larger than the lens, leaving an aphakic space. Common among deepsea anglerfish is the strong sexual dimorphism in melanocetids: while females may reach a length of 18 cm (7 in) or more, males remain under 3 cm (1 in). Aside from jaw teeth, males also lack lures. Pelvic fins are absent in both sexes. All fins are rounded with slightly incised membranes; the pectoral fins are small. The single dorsal fin is positioned far back from the head, larger than and above the retrorse anal fin.
Females have large, highly distensible stomachs which give the ventral region a flabby appearance. In life, black seadevils are a dark brown to black. The skin is extremely soft and easily abraded during collection or even by simple handling.
The Melanocetidae appear to buck the trend in deepsea anglers, in that the males—despite not feeding as an adult and thus being little more than couriers of sperm —are free-living rather than parasitic. A brief attachment to the female does probably occur, however, as evidenced by a case of mistaken identity: A male humpback anglerfish was found attached to the lip of a female horned lantern fish (Centrophryne spinulosa) of an unrelated (though also nonparasitic) family of anglerfish, Centrophrynidae. Little else is known of their reproduction: They are presumed to not be guarders, releasing buoyant eggs into the water which become part of the zooplankton.
While adults have been trawled from as deep as 3,000 m (9,900 ft), larvae appear to remain in the upper 100 m (330 ft) of the water column and gradually descend with maturity. Males likely outnumber—and mature well before—females by a wide margin.
The females use their bioluminescent "fishing poles" to lure both conspecifics and prey, which include crustaceans and small fish such as lanternfish and bristlemouths; the seadevils' highly distensible stomachs also allow them to swallow prey larger than themselves, which is an important adaptation to life in the lean depths. In contrast with males, females are poor swimmers and spend most of their time motionless, waiting for something to approach their lures. Predators of black seadevils are not well known, but include lancetfish. Bruce Robison of California Monterey Bay Aquarium Research Institute, who led the dive, spotted a Black Seadevil at 600 m (1,900 ft) during an exploration of the Monterey Canyon via a remote-operated diving vehicle on Nov. 22, 2014. [9]
The footballfish form a family, Himantolophidae, of globose, deep-sea anglerfishes found in tropical and subtropical waters of the Atlantic, Indian, and Pacific Ocean. The family contains 23 species, all of which are classified in a single genus, Himantolophus.
Fanfins or hairy anglerfish are a family, Caulophrynidae, of marine ray-finned fishes within the order Lophiiformes, the anglerfishes. The fishes in this family are found almost around the world in the deeper, aphotic waters of the oceans.
Double anglers, the family Diceratiidae, is a small and little known family of rarely encountered marine ray-finned fishes belonging to the order Lophiiformes, the anglerfishes. The two genera and seven species of this family are found in the deeper waters of the tropical and subtropical Atlantic, Indian and Pacific Oceans. They are distinguished from other deep sea anglerfishes by the possession of a second bioluminescent cephalic spine. The fishes in this family were known only from metamorphosed females and the males were not described until 1983.
Thaumatichthyidae, the wolftrap anglers, is a small family of marine ray-finned fishes, also called the wolftrap seadevils, classified within the suborder Ceratioidei, the deep-sea anglerfishes. They have distinctive upper jaws with movable premaxillaries that can be lowered to form a cage-like trap around the much shorter lower jaw.
Bertella is a monospecific genus of marine ray-finned fish belonging to the family Oneirodidae, the dreamers, a family of deep sea anglerfishes. The only species in the genus is Bertella idiomorpha and this can be distinguished from other members of the family by the structure of its hyomandibular bone.
The toothed seadevil, spiny seadevil or netbeard seadevil,, is a rarely seen deep-sea anglerfish found in the mesopelagic and bathypelagic zones in Oceans around the World. It is the only species in the family Neoceratidae, and is unique amongst the deep-sea anglerfish in lacking an illicium and esca, and in having large teeth placed on the outside of its jaws.
Tyrannophryne is a monospecific genus of marine ray-finned fish belonging to the family Oneirodidae, the dreamers, a family of deep-sea anglerfishes. The only species in the gneus is Tyrannophryne pugnax, the tyrant devil. Like other oneirodids, T. pugnax is a bathypelagic fish with a bioluminescent lure. It is known only from two adolescent female specimens, one caught in 1928 near Tahiti-Rarotonga, and the other in 1956 northwest of Bikini Atoll.
The anglerfish are fish of the teleost order Lophiiformes. They are bony fish named for their characteristic mode of predation, in which a modified luminescent fin ray acts as a lure for other fish. The luminescence comes from symbiotic bacteria, which are thought to be acquired from seawater, that dwell in and around the sea.
The humpback anglerfish is a species of black seadevil in the family of Melanocetidae, which means "black whale" in Greek. The species is named after James Yate Johnson, the English naturalist who discovered the first specimen in Madeira in 1863. The common names include anglerfish, viperfish and fangtoothfish.
Caulophryne polynema is a species of marine ray-finned fish belonging to the family Caulophrynidae, the fanfins. This species is a deepwater species which is found in the Atlantic and Pacific Oceans. Like other deepwater anglerfishes it shows extreme sexual dimorphism with the males being much smaller than the females and acting as sexual parasites of the females.
Diceratias is a genus of deep sea marine ray-finned fish belonging to the family Diceratiidae, the double anglers. These fishes are found in the Eastern Atlantic and Indo-Pacific regions.
Danaphryne is a monospecific genus of marine ray-finned fish belonging to the family Oneirodidae, the dreamers, a family of deep sea anglerfishes. The only species in the genus is Danaphryne nigrifilis which is found in the tropical and temperate regions of all of the world's oceans.
Oneirodes is a genus of is a genus of marine ray-finned fish belonging to the family Oneirodidae, the dreamers, a family of deep sea anglerfishes. These predatory, deep-sea fishes are found around the world. This is the type genus, and the most speciose genus, of the family Oneirodidae. They are sexually dimorphic but, like most taxa within their family, the small males are free living and are not sexual parasites on the larger females. Only the females are used to identify the species in this genus as no species specific charaxcters have been found for males.
Puck pinnata, the mischievous dreamer, is a species of marine ray-finned fish belonging to the family Oneirodidae, the dreamers, a family of deep-sea anglerfishes. This species is known from four metamorphosed female specimens each collected from four separate locations, three in the Pacific Ocean and one in the Atlantic Ocean. As with all other species in the family, it is a pelagic, deep-water fish that is a member of the abyssal ecosystem. It is the only known species in the monospecific genus Puck.
Pentherichthys is a monospecific genus of marine ray-finned fish belonging to the family Oneirodidae, the dreamers, a family of deep-sea anglerfishes. The only species in the genus is Pentherichthys atratus which is found in the bathypelagic zones of the tropical and subtropical Atlantic, Indian and Pacific Oceans. The males of this species are dwarfed and are not parasitic on the females.
Caulophryne pelagica is a species of marine ray-finned fish belonging to the family Caulophrynidae, the fanfins. This species is a deepwater species which is found in the eastern Atlantic, Indian Ocean, Pacific Ocean and Southern Ocean. Its biology is little known but similar species show extreme sexual dimorphism with the very small makes seeking out and attaching themselves to the much larger females and becoming parasites of the females.
Caulophryne jordani, the fanfin angler, is a species of marine ray-finned fish belonging to the family Caulophrynidae, the fanfins. This species is a deepwater species which is found in Oceanic waters around the world. Like other deepwater anglerfishes it shows extreme sexual dimorphism with the males being much smaller than the females and acting as sexual parasites of the females.
Diceratias bispinosus, the two-rod angler, is a species of deep sea marine ray-finned fish belonging to the family Diceratiidae, the double anglers. This species is found in the Indo-Pacific region.
Chaenophryne draco, the smooth dreamer, or smooth-headed dreamer, is a species marine ray-finned fish belonging to the family Oneirodidae, the dreamers, a family of deep sea anglerfishes. This predatory, deep-sea fish is found in the tropical and subtropical oceans around the world. Like other deep-sea anglerfishes it is sexually dimorphic with the matamorphosed females dwarfing the metamorphosed males, the males are not sexual parasites.
Ceratioidei, the deep-sea anglerfishes or pelagic anglerfishes, is a suborder of marine ray-finned fishes, one of four suborders in the order Lophiiformes, the anglerfishes. These fishes are found in tropical and temperate seas throughout the world. One of the better known traits of the deep-sea anglerfishes is their extreme sexual dimorphism where the males are many times smaller than the females, the males seek out females and use their sharp teeth to clamp onto the females where he remains for the rest of his life, in some species he becomes part of the female. This is the only known natural example of a process called parabiosis. Another common trait of deep-sea anglerfishes is that they use bioluminescence on their esca to attract prey in the darkness of the deep oceans they inhabit.