''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.

Taxonomy

''Caulophryne pelagica'' was first formally described in 1902 as ''Melanocetus pelagicus'' by the German zoologist

August Brauer August Bernhard Brauer (3 April 186310 September 1917) was a German zoologist. Brauer was born in Oldenburg. He studied natural sciences at the Universities of Bonn, Berlin and Freiburg, obtaining his doctorate in 1895 with a thesis on the ciliat ...

with its type locality given as west of the

Chagos Archipelago The Chagos Archipelago () or Chagos Islands (formerly the Bassas de Chagas, and later the Oil Islands) is a group of seven atolls comprising more than 60 islands in the Indian Ocean about 500 kilometres (310 mi) south of the Maldives archi ...

in the Indian Ocean from Valdivia station 228 from a depth of in water with a bottom depth of . This species is classified within the genus '' Caulophryne'' which is one of two genera within the family Caulophrynidae. The 5th edition of ''

Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...

'' classifies the Caulophrynidae within the suborder Ceratioidei of the order Lophiiformes, the anglerfishes.

Etymology

''Caulophryne pelagica'' is a species within the genus ''Caulophryne'', this name is a combination of ''caulis'', which mean" stem", an allusion to the stem-like base of the illicium, with ''phryne'', meaning "toad", a suffix commonly used in the names of anglerfish genera. Its use may date as far back as Aristotle and Cicero, who referred to anglerfishes as “fishing-frogs” and “sea-frogs,” respectively, possibly because of their resemblance to frogs and toads. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''pelagica'' derives from ''pelagios'', meaning "of the open sea", a reference to the

bathypelagic The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The bathypelagic ...

environment the holotype was collected from.

Description

''Caulophryne pelagica'' has a high degree of sexual dimorphism. The females have short, round bodies with large mouths. The lower jaw reaches back past the base of the pectoral fin. The teeth in the jaws are thin, backwards curving and depressible. They have highly elongated 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, with the soft rays of these fins resembling long threads. There are 8 fin rays in the caudal fin. They do not have

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s. The sensory cells of the

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

system are at the tips of the filamentous rays of the dorsal and anal fins. They have a simple esca, or lure, which lacks a bulb but which may have filaments or appendages. The skin is naked and they do not have any dermal spines. The males are much smaller than the females and have more elongated bodies. They have large eyes and large nostrils, with large olfactory receptors. They have no teeth in the jaws, although there are tooth-like structures on the jaw bones which are used to attach to the larger female. The male do not have elongated dorsal and anal fins but so have large pectoral fins. ''C. pelagica'' has a dark coloured illlicium, that has no translucent filaments along its length other than near to the esca and which has a length equivalent to between 18% and 125.8% of the

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

, the longer the fish is, the greater the relative length of the illicium. The esca has between 5 and 7 elongated, filamentous appendages, 2 to 4 unbranched appendages close to its base and 3 or 4 branched appendages near its tip. The dorsal fin has between 14 and 17 soft rays while the anal fin has 12 soft rays. The maximum published total length is for females.

Distribution and habitat

''Caulophryne pelagica'' is found in the eastern Atlantic Ocean, the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region and the Southern Ocean. In the Eastern Atlantic it is known only from the waters off Cape Verde, Gambia, Senegal, Mauritania and Western Sahara. In the Indo-Pacific it has a wide distribution from Somalia and the Madives east to Hawaiiand in the eastern Pacific where it has been collected off Alaska, Baja California, the Gulf of Panama and Ecuador to as far south as 4°S, while in the Southern Ocean it is known from New Zealand and Australia. This species is found in mesopelagic and

zones at depths between .

Biology

''Caulophryne pelagica''s biology is almost unknown. The anglerfishes in this genus are predators using the illicium and ecsa to lure in prey. The males are much smaller than the females and have highly developed sensory apparatus which are used to find the females which the males attach themselves to and become sexual parasites of. There are, howver, no known male specimens for this species.

References

{{Taxonbar, from=Q2583726 Caulophrynidae Deep sea fish Fish described in 1902 Taxa named by August Brauer