''Stephanolepis hispidus'', the planehead filefish, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

bony fish Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ...

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 ...

Monacanthidae.

Description

Planehead filefish grow to a maximum length of , but are more typically about long. Their colour is cryptic, being a more or less mottled pale brown, olive, or green on a light-coloured background, sometimes with darker brown splotches and streaks. The fish are laterally compressed and deep bodied. Their snout is elongated with a terminal mouth. The large yellow eyes are set high on the head and above is a prominent retractable spine. This is the anterior of the two spines associated with the long dorsal fin, which also has 29 to 35 soft rays. The anal fin has no spines and between 30 and 35 soft rays. Theie pectoral fins are small and the tail fin is large and fan-shaped, often with two darker-coloured bands.''Stephanolepis hispidus'' (Linnaeus, 1766)
FishBase. Retrieved 2012-01-04.''Stephanolepis hispidus''
Marine Species Identification Portal. Retrieved 2012-01-04. Planehead filefish are

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 ...

. In mature males, the second soft ray of the dorsal fin becomes greatly elongated and the scales on either side of the caudal peduncle develop into a patch of bristles. The elongated ray reaches between 104 and 128 mm. Females do not develop secondary sexual characteristics. They tend to have greater body depth than males, but variation in this trait exists in both sexes and overlap in measurements are recorded.

Distribution and habitat

The planehead filefish is found in the Atlantic Ocean at depths of up to . Its range extends from

Nova Scotia Nova Scotia is a Provinces and territories of Canada, province of Canada, located on its east coast. It is one of the three Maritime Canada, Maritime provinces and Population of Canada by province and territory, most populous province in Atlan ...

Uruguay Uruguay, officially the Oriental Republic of Uruguay, is a country in South America. It shares borders with Argentina to its west and southwest and Brazil to its north and northeast, while bordering the Río de la Plata to the south and the A ...

in the west and from the

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

Angola Angola, officially the Republic of Angola, is a country on the west-Central Africa, central coast of Southern Africa. It is the second-largest Portuguese-speaking world, Portuguese-speaking (Lusophone) country in both total area and List of c ...

in the east. It is found near the seabed on reefs and over sandy and muddy sea floors. It is often found among ''

Sargassum ''Sargassum'' is a genus of brown macroalgae ( seaweed) in the order Fucales of the Phaeophyceae class. Numerous species are distributed throughout the temperate and tropical oceans of the world, where they generally inhabit shallow water and ...

'' seaweed.

Biology

In the Canary Islands, the growth and ageing of the planehead filefish have been studied. Spawning takes place in the summer and the age of the fish is established by using the fast and slow growth rings found in the anterior dorsal fin spine. The species has a lifespan of about three years and reaches half its final length by the end of its first year.

Uses

The planehead filefish can be used for human consumption. In the Canary Islands, it is caught in fish traps and at one time was considered to be a by-catch, incidental to the capture of other, more desirable fish. Since the 1980s, though, it has become a target species in its own right and by 2000, concerns about overfishing had arisen.

References

External links

* {{Taxonbar, from=Q107054337 Monacanthidae Fish described in 1766 Fish of the Atlantic Ocean Fish of Africa Fish of North America Fish of South America Fish of West Africa Taxa named by Carl Linnaeus