The smoothback angelshark (''Squatina oculata'') is an

angelshark The angelsharks are a group of sharks in the genus ''Squatina'' of the family Squatinidae. They commonly inhabit sandy seabeds close to in depth. Many species are now classified as critically endangered by the International Union for Conservat ...

of the

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 ...

Squatinidae found in the eastern

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

and

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

Description

The smoothback angelshark can reach a length of up to 1.6 metres. As with other angelsharks, its body is flattened by very wide pectoral fins, giving it the appearance of a long

ray Ray may refer to: Fish * Ray (fish), any cartilaginous fish of the superorder Batoidea * Ray (fish fin anatomy), a bony or horny spine on a fin Science and mathematics * Ray (geometry), half of a line proceeding from an initial point * Ray (g ...

. Unlike in rays, however, the pectoral fins are clearly separated from the body. They have two

dorsal fins A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

and no

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 ...

. The shark is grey-brown with small, round black and white spots and a distinctive white neck spot. The bases and tips of the pectoral fins have symmetrical dark spots, as well as the base of the tail and the lower edge of the dorsal fins. Eyespots with white edges may be present. The outer edges of the dorsal and

caudal fins Fins are distinctive anatomical features composed of bony spine (zoology), spines or Ray (fish fin anatomy), 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 bon ...

are white, those of the thoracic and pelvic fins dark. Enlarged spines are located in the snout area and around the eyes, but not on the back. The eyes are on the top of the head with a strong concave surface between them. The outer nostrils are covered with short barbels. The spiracles are large. There are five lateral, lower gill openings. The nasal valves are either only slightly fringed or smoothly edged, the barbels either forked or lobed.

Distribution

The smoothback angelshark is found on

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

's western coast down to

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

, as well as in the

. It lives in the outer margins of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

at depths between 20 and 500 meters, although it usually resides in depths above 100 meters.

Biology

The data for the biology of this species is limited. It is known to feed on small sharks,

bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilag ...

cephalopods A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, an ...

and crabs. Like all angelsharks it is

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...

. The pups are 24–27 centimetres long at birth.

Threats and relationship with humans

The smoothback angelshark is critically endangered. Like the

sawback angelshark The sawback angelshark (''Squatina aculeata'') is an angelshark of the family Squatinidae It is one of rarest species of sharks known to date, and one of the three species of angelsharks that inhabits the Mediterranean. The Sawback angelshark li ...

(''Squatina aculeata'') found in the same habitat, this species used to be very common. It is most threatened by the intensive fishing in coastal areas and continental shelves by drift nets, gillnets and longlines, which affects most of its range off the African coast. The sharks are caught as by-catch, causing the stock to plummet dramatically in the last 50 years. The species has therefore disappeared in large areas of the northern Mediterranean and in African coastal waters. Together with two related species, the

and the

, the Portuguese fisheries authorities in the area off

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to ...

and

Mauritania Mauritania (; ar, موريتانيا, ', french: Mauritanie; Berber: ''Agawej'' or ''Cengit''; Pulaar: ''Moritani''; Wolof: ''Gànnaar''; Soninke:), officially the Islamic Republic of Mauritania ( ar, الجمهورية الإسلامية ...

saw a fall of 95% between 1990 and 1998. The pressure of fisheries on the species distribution is likely to intensify in the future.

Description

Distribution

Biology

Threats and relationship with humans

References

Further reading