''Caulophryne'' is a genus of marine

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

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 ...

Caulophrynidae, the fanfins or hairy anglerfishes. These fishes are found throughout the non-polar oceans of the world.

Taxonomy

''Caulophryne'' was first proposed as

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 1896 by the American

ichthyologists 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 ...

George Brown Goode and Tarleton Hoffman Bean when the described ''Caulophryne jordani''. 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 ''C. jordani'' was collected from the

Gulf Stream The Gulf Stream is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States, then veers east near 36°N latitude (North Carolin ...

off

Long Island, New York Long Island is a densely populated continental island in southeastern New York (state), New York state, extending into the Atlantic Ocean. It constitutes a significant share of the New York metropolitan area in both population and land are ...

at 39°27'N, 71°15'W,

Albatross Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Paci ...

station 2747 from a depth between . ''Caulophryne'' and '' Robia'' are the two genera making up the family Caulophrynidae. 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 the Caulophrynidae within the suborder

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 Lophiiformes, the anglerfishes.

Etymology

''Caulophryne'' is a combination of ''caulis'', which mean" stem", an allusion to the stem-like base of the

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

, with ''phryne'', meaning "toad", a suffix 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.

Species

''Caulophryne'' currently has four recognized species classified within it: *

Characteristics

''Caulophryne'' fanfins have a high degree of

sexual dimorphism 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 ...

, akin to other anglerfish. The females have short, round bodies with large mouths. The lower jaw reaches back past the base of the

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

. The teeth in the jaws are thin, backwards curving and depressible. They have highly elongated

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

and

anal 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 o ...

s, with the soft rays of these fins resembling long threads. There are 8 fin rays in 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 do not have

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

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 epithelia ...

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 receptor Olfactory receptors (ORs), also known as odorant receptors, are chemoreceptors expressed in the cell membranes of olfactory receptor neurons and are responsible for the detection of odorants (for example, compounds that have an odor) which give ...

s. 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. The juveniles have

s that are lost when they metamorphose into adults, although the relict pelvic bones are retained. This genus differs from ''Robia'' in their markedly shorter illicium which measures approximately as opposed to around in ''Robia''. The two genera also differ by the

count Count (feminine: countess) is a historical title of nobility in certain European countries, varying in relative status, generally of middling rank in the hierarchy of nobility. Pine, L. G. ''Titles: How the King Became His Majesty''. New York: ...

and length of the fin rays in the dorsal and anal fins; ''Caulophryne'' possesses between 14 and 22 rays in the dorsal fin with the longest ray being 70% of the fish's

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 ...

; in the anal fin there are between 12 and 19 fin rays with the longest being 60% of standard length. In ''Robia'' there are 6 rays in the dorsal fin, the longest is 65% of the standard length, and 5 rays in the anal fin with the longest being 40% of the standard length. The largest species in the genus is ''C. polynema'' with a maximum published

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

of .

Distribution and habitat

''Caulophryne'' fanfins are found in the Atlantic, Indian and Pacific Oceans where they live 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 ...

Biology

''Caulophryne'' fanfins are predators on other fishes. They reproduce by means of pelagic eggs which hatch into pelagic larvae. The short, rounded larvae have swollen skin and well-developed pectoral and pelvic fins, the pelvic fins being lost as they metamorphose. Both larval males and females have a basic illicium. Metamorphosis starts at a

of . The large, well-developed eyes and olfactory apparatus of the metamorphosed males are used to detect and home in on a species-specific chemical released by the female to attract males. When the male finds a female he bites her and the tissue and circulatory systems of the pair fuse, he becomes a sexual parasite on the female and is nourished by the female through shared blood. For the remainder of his life he is attached to the female and fertilises her eggs. A pair of '' C. jordani'' was observed

in-situ is a Latin phrase meaning 'in place' or 'on site', derived from ' ('in') and ' ( ablative of ''situs'', ). The term typically refers to the examination or occurrence of a process within its original context, without relocation. The term is use ...

by a

submersible A submersible is an underwater vehicle which needs to be transported and supported by a larger ship, watercraft or dock, platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent ope ...

of the Rebikoff-Niggeler Foundation in 2018, which was the first time this genus was observed alive. The extended fin rays were observed to spread all around the female, each independently controlled by muscle, and pinpointed with bioluminescence. It is thought that these filaments fulfill a similar role as a cat's

whiskers Whiskers, also known as vibrissae (; vibrissa; ) are a type of stiff, functional hair used by most therian mammals to sense their environment. These hairs are finely specialised for this purpose, whereas other types of hair are coarser as ta ...

, acting as a "network of sensory antennae, a kind of sphere of tactility around the fish", which would allow the female to detect nearby prey items. The bioluminescence on the rays is speculated to be

mimicry In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. In the simples ...

of a larger or unpalatable organism, such as a

jellyfish Jellyfish, also known as sea jellies or simply jellies, are the #Life cycle, medusa-phase of certain gelatinous members of the subphylum Medusozoa, which is a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animal ...

with stinging tentacles. Alternatively, they may supplement the ilicium in luring prey closer.

References

{{Taxonbar, from=Q2943109 Caulophrynidae Marine fish genera Taxa named by George Brown Goode Taxa named by Tarleton Hoffman Bean