The jack-knifefish (''Eques lanceolatus'') is a species 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 ...

Sciaenidae Sciaenidae is a family (biology), family of ray-finned fishes belonging to the Order (biology), order Acanthuriformes. They are commonly called drums or croakers in reference to the repetitive throbbing or drumming sounds they make. The family co ...

, the drums and croakers. It is native to the western

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

, where its distribution extends along the eastern coasts of the Americas from the Carolinas in the United States to

Brazil Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...

, including the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

. Other common names include donkey fish and lance-shaped ribbonfish.

Taxonomy

The jack-knifefish was first formally described as ''Chaetodon lanceolatus'' in 1758 by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in the 10th edition of his ''

Systema Naturae ' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...

'' with its type locality given, erroneously as India, when it should have been the Bahamas. In 1793 the German

physician A physician, medical practitioner (British English), medical doctor, or simply doctor is a health professional who practices medicine, which is concerned with promoting, maintaining or restoring health through the Medical education, study, Med ...

and

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

Marcus Elieser Bloch Marcus Elieser Bloch (1723–1799) was a German physician and naturalist who is best known for his contribution to ichthyology through his multi-volume catalog of plates illustrating the fishes of the world. Brought up in a Hebrew-speaking Jewish ...

described a new species, ''Eques americanus'', from the Western Atlantic and placed it in the new monospecific genus ''Eques''. Bloch's genus name was considered to be preoccupied by a name Linnaeus had used for a subgenus of ''

Papilio ''Papilio'' is a genus in the swallowtail butterfly family, Papilionidae, as well as the only representative of the tribe Papilionini. The word ''papilio'' is Latin for butterfly. It includes the common yellow swallowtail ('' Papilio machaon'') ...

'', and

Constantine Samuel Rafinesque Constantine Samuel Rafinesque-Schmaltz (; 22 October 178318 September 1840) was a French early 19th-century polymath born near Constantinople in the Ottoman Empire and self-educated in France. He traveled as a young man in the United States, ult ...

created ''Equites'' to replace Bloch's ''Eques'', however, Linnaeus's name is considered to be invalid so ''Eques'' is now considered valid. Fishbase treats the genus as monospecific with this species as the only species but other authorities include the spotted drum (''Equetus punctatus'') in the genus, treating ''Equetus'' as a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''Eques''. This taxon has been placed in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Sciaeninae by some workers, but 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 ...

'' does not recognise subfamilies within the Sciaenidae which it places in 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 ...

Acanthuriformes Acanthuriformes is a large, diverse order of mostly marine ray-finned fishes, part of the Percomorpha clade. In the past, members of this clade were placed in the suborders Acanthuroidea and Percoidea of the order Perciformes, but this treatment ...

Description

This fish reaches about 25 centimeters in maximum length. The first dorsal fin is very tall. The body is gray in color with three brown or black bands. The first two bands are small and vertical, and the third extends from the tip of the tall dorsal fin down the body to the tip of the tail fin.

Habitat

This marine fish is mostly found along coasts in waters up to 60 meters deep, especially in reef habitat.

Biology

This species feeds on small invertebrates, and sometimes detritus.

Uses

This species is sometimes kept in marine aquaria. It can be bred in captivity.

Conservation

This species is not considered to be threatened. The aquarium trade does not significantly impact populations, even though it is valuable and easy to collect from the wild. It has a wide distribution, and in many areas it is a common species.

References

External links

* {{Taxonbar, from=Q1497325 Eques Fish described in 1758 Taxa named by Carl Linnaeus Fish of the Dominican Republic Fish of the Atlantic Ocean Marine fish of Brazil