Fanfins or hairy anglerfish are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

, Caulophrynidae, of marine

ray-finned fishes Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or h ...

within the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Lophiiformes 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 (the esca or illicium) acts as a lure for other fish. The luminescence c ...

, the anglerfishes. The fishes in this family are found almost around the world in the deeper,

aphotic The aphotic zone (aphotic from Greek prefix + "without light") is the portion of a lake or ocean where there is little or no sunlight. It is formally defined as the depths beyond which less than 1 percent of sunlight penetrates. Above the aphot ...

waters of the oceans.

Taxonomy

The fanfin family, Caulophrynidae, was first proposed 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, 33,400 species of fish had been described as of October ...

George Brown Goode and

Tarleton Hoffman Bean Tarleton Hoffman Bean (October 8, 1846 – December 28, 1916) was an American ichthyologist. Biography and education Tarleton Hoffman Bean was born to George Bean and Mary Smith Bean in Bainbridge, Pennsylvania, on October 8, 1846. He attended ...

. 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. This family was thought to be basal within the

suborder Order ( la, ordo) 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 ...

Ceratioidei of the anglerfish order Lophiiformes, but

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analyses have recovered it as forming a

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

containing Gigantactinidae,

Neoceratiidae The toothed seadevil, spiny seadevil or netbeard seadevil, ''(Neoceratias spinifer)'', is a rarely seen deep-sea anglerfish found in the mesopelagic and bathypelagic zones of the western central Pacific Ocean. It is the only species in the famil ...

, and Linophrynidae, and so they are deeply embedded within the suborder. However,

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

studies show that the familial relationships within the Ceratoidei are still to be fully resolved and Caulophrynidae may be the most basal taxon in the suborder.

Etymology

The fanfin family, Caulophrynidae, takes its name from the genus ''Caulophryne''. This name 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 (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...

and

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

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

Genera

The fanfin family, Caulophrynidae, contains the following two genera:

Characteristics

Fanfins have a high degree of

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

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

pectoral 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 ...

. 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 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 ...

. 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 simlpe

esca 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 (the esca or illicium) acts as a lure for other fish. The luminescence co ...

, 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 ri ...

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 are the only ceratoid anglerfishes to have

s. The largest species of fanfin is '' Caulophryne polynema'' with a maximum published

total 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 ...

of .

Distribution and habitat

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 bathypelagic ...

Biology

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

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 ...

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.

References

{{Taxonbar, from=Q1478708 Caulophrynidae Ceratioidei Deep sea fish Taxa named by George Brown Goode Taxa named by Tarleton Hoffman Bean