''Chaenophryne'' is a genus of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Oneirodidae Oneirodidae, the dreamers are a family of marine ray-finned fishes belonging to the order Lophiiformes, the anglerfishes. These fishes are deepwater fishes found in the Atlantic, Indian and Pacific Oceans, and it is the most diverse family of f ...

, the dreamers, a family of deep-sea

anglerfish The anglerfish are ray-finned fish in the order Lophiiformes (). Both the order's common name, common and scientific name comes from the characteristic mode of predation, in which a modified dorsal Fish fin#Ray-fins, fin ray acts as a Aggressiv ...

es. These predatory, deep-sea fishes are found in the tropical and subtropical oceans around the world. Like other deep-sea anglerfishes, they are sexually dimorphic, with the matamorphosed females dwarfing the metamorphosed males. The males are not

sexual parasite Fish reproductive organs include testes and ovaries. In most species, gonads are paired organs of similar size, which can be partially or totally fused. There may also be a range of secondary organs that increase reproductive fitness. The gen ...

Taxonomy

''Chaenophryne'' was first proposed as a

monospecific genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

in 1925 by the British

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish (Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 35,800 species of fish had been described as of March 2 ...

Charles Tate Regan Charles Tate Regan (1 February 1878 – 12 January 1943) was a British ichthyology, ichthyologist, working mainly around the beginning of the 20th century. He did extensive work on fish classification schemes. Born in Sherborne, Dorset, he was ...

when he described ''Chaenophryne longiceps'', giving its type locality as 7°30'N, 79°19'W, off the

Gulf of Panama The Gulf of Panama () is a gulf of the Pacific Ocean off the southern coast of Panama, where most of eastern Panama's southern shores adjoin it. The Gulf has a maximum width of , a maximum depth of and the size of . The Panama Canal connects the ...

at a depth of . The 5th edition of

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

classifies this genus in the family Oneirodidae in the

suborder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Ceratioidei Ceratioidei, the deep-sea anglerfishes or pelagic anglerfishes, is a suborder of marine ray-finned fishes, one of five suborders in the order Lophiiformes, the anglerfishes. These fishes are found in tropical and temperate seas throughout the wor ...

of the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Lophiiformes The anglerfish are ray-finned fish in the order Lophiiformes (). Both the order's common and scientific name comes from the characteristic mode of predation, in which a modified dorsal fin ray acts as a lure for prey (akin to a human angler, ...

Etymology

''Chaenophryne'' is a combination of ''chaeno'', which means "gape", with phryne, meaning "toad". What this name alludes to was not explained by Regan but the first part may refer to the wide mouth of ''C. longiceps''. The second part is a suffix commonly used in the names of anglerfish genera. Its use for these fishes may date as far back as

Aristotle Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...

and

Cicero Marcus Tullius Cicero ( ; ; 3 January 106 BC – 7 December 43 BC) was a Roman statesman, lawyer, scholar, philosopher, orator, writer and Academic skeptic, who tried to uphold optimate principles during the political crises tha ...

, who referred to anglerfishes as "fishing-frogs" and "sea-frogs", respectively, possibly because of their resemblance to frogs and toads.

Species

''Chaenophryne'' has five recognized species classified within it: * '' Chaenophryne draco'' Beebe, 1932 (Smooth-headed dreamer) * '' Chaenophryne longiceps'' Regan, 1925 (Can-opener smooth-headed dreamer) * '' Chaenophryne melanorhabdus'' Regan & Trewavas, 1932 * '' Chaenophryne quasiramifera'' Pietsch, 2007 * '' Chaenophryne ramifera'' Regan & Trewavas, 1932

Characteristics

''Chaenophryne'' dreamers are, like other deep sea anglerfishes,

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, and both the metamorphosed males and females are distinguished from other genera of Oneirodidae by the long and slender suboperculum, which has a tapering point at its upper end, and by having a slightly concave rear edge to the operculum. The metamorphosed females do not have any sphenotic spines, although there are blunt ridges on the parietal and post-temporal bones. The rear edge of the frontal bone is highly curved. They have pigmented skin which clearly extends past the base of the

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

. They have a pigmented snout, the rear nostril is separate from the eye, and there are 17-27 teeth on the lower denticular. The largest species in the genus is ''C. longiceps'' with a maximum published

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

of , while the smallest is ''C. ramifera'' with a maximum published

of .

Distribution and habitat

''Chaenophryne'' dreamers are found in subtropical and tropical waters in the Atlantic, Indian and Pacific Oceans. They are found in the

bathypelagic zone 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 bathypela ...

at depths between .

Biology

''Chaenophryne'' dreamers are predatory, feeding on fishes, cephalopods and crustaceans. The males are dwarfed compared to the females but are non-parasitic.

References

{{Authority control Oneirodidae Marine fish genera Taxa named by Charles Tate Regan