''Haplophryne mollis'', the ghostly seadevil or soft leftvent angler, is a species of

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 ...

in 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 ...

Linophrynidae and is the only species in the genus ''Haplophryne''. It is found in 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 bathypela ...

and

mesopelagic zone The mesopelagic zone (Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light, and begins ...

s of tropical and subtropical parts of the world's oceans at depths down to about .

Taxonomy

''Haplophryne'' 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 1912 by the English

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 ...

with ''Aceratias mollis'' as its only species and its

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

monotypy 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 ...

. ''A. mollis'' was first formally described in 1902 by the German

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

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 cilia ...

with its type locality given as the central Indian Ocean from a depth of , collected on the

Valdivia Expedition The ''Valdivia'' Expedition, or ''Deutsche Tiefsee-Expedition'' (German Deep Sea Expedition), was a scientific expedition organised and funded by the German Empire under Kaiser Wilhelm II and was named after the ship which was bought and outfit ...

. 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 taxon in the family Linophrynidae, within 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 ...

, the deep sea anglerfishes, 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

''Haplophryne'' is a combination of ''haplo'' and ''phryne''. ''Haplo'' means "single", Regan did not explain this what this alluded to but it may be to the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''A. mollis'', a male which was "without nasal papillae". ''Phryne'', which means "toad", is commonly used in the names of anglerfish genera. Its use 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. 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 ...

, ''mollis'', means "soft" an allusion to the thick, soft and unpigmented skin of the holotype.

Description

Adult female ''Haplophryne mollis'' are much larger than adult males, with a maximum length of , but is a more common length. As in other angler fish, the front dorsal fin is replaced by a lure (

illicium ''Illicium'' is a genus of flowering plants treated as part of the family Schisandraceae,

or esca) that protrudes forward and over the mouth to attract prey, but in this species this just consists of a flap of skin and there is no "fishing rod". The fish has spine-like ornamentation above the eyes and at the corners of the jaws. The head is large and angular, with a very wide mouth armed with numerous small teeth in both jaws. The dorsal fin, which has no spines but consists of three soft rays, is set far back on the body; the anal fin also has three soft rays and the tail is rounded. Unlike most other deepsea anglerfish, ''H. mollis'' lacks pigmentation, and both sexes appear pallid and translucent, with the musculature and portions of the skeleton clearly showing through the skin. Free-living males only grow to about , and differ from the adult and juvenile females by the noticeable lack of a short, bubble-like esca and having comparatively small fins. Juvenile females lack the spinous ornamentation on the head.

Distribution

Because of the great depths at which this fish lives, it is seldom encountered by humans. In 2009 it was reported that 88 known female specimens had been observed. The type specimen was described by the German zoologist

in 1902 from the Indian Ocean. Another Indian Ocean specimen was a free-living male caught off

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

. Other specimens have been trawled from the Atlantic Ocean, the

Caribbean Sea The Caribbean Sea is a sea of the Atlantic Ocean, North Atlantic Ocean in the tropics of the Western Hemisphere, located south of the Gulf of Mexico and southwest of the Sargasso Sea. It is bounded by the Greater Antilles to the north from Cuba ...

and the

Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...

, between 55°N and 40°S. Further specimens have been found in the Pacific Ocean off eastern Australia,

New Caledonia New Caledonia ( ; ) is a group of islands in the southwest Pacific Ocean, southwest of Vanuatu and east of Australia. Located from Metropolitan France, it forms a Overseas France#Sui generis collectivity, ''sui generis'' collectivity of t ...

and

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

, with isolated findings near

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

and in 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 ...

. It is found in the

and

s of tropical and subtropical parts of the world's oceans at depths down to about .

Life cycle and ecology

Male ''H. mollis'' are at first free-living, but when they have found a female, they latch onto her with their teeth. In most anglerfish the point of attachment for the male is on the belly, close to the

anus In mammals, invertebrates and most fish, the anus (: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the ''exit'' end of the digestive tract (bowel), i.e. the opposite end from the mouth. Its function is to facil ...

, but in ''H. mollis'' the attachment site can be anywhere on the head or body, and in one case, a male attached to the female's esca (lure). The males orient themselves in random directions, and there may be more than one male per female. A papilla, or conical fleshy protuberance, grows at the site of attachment which may assist the male to establish a good grip. The mouth of the male is partially blocked by the papilla, but an opening usually remains at either side which suffices for allowing a flow of water over the gills. As time passes, the male becomes fused to the female and their tissues combine. The male can be considered as a

parasite Parasitism is a Symbiosis, close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the Host (biology), host, causing it some harm, and is Adaptation, adapted str ...

of the female but only about 30% of mature females encountered have an attached male, so many females may never encounter a mate, and remain in a solitary, non-reproductive state for the duration of their lives.

References

External links

* * {{Taxonbar, from=Q2134412 Linophrynidae Marine fish Fish described in 1902 Taxa named by August Brauer Monotypic vertebrate genera Monotypic fish genera Monotypic marine fish genera Monotypic ray-finned fish genera