| Smoothback angelshark | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Chondrichthyes |
| Order: | Squatiniformes |
| Family: | Squatinidae |
| Genus: | Squatina |
| Species: | S. oculata |
| Binomial name | |
| Squatina oculata Bonaparte, 1840 | |
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| Range of smoothback angelshark (in blue) | |
The smoothback angelshark (Squatina oculata) is an angelshark of the family Squatinidae found in the eastern Atlantic and Mediterranean.
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. Unlike in rays, however, the pectoral fins are clearly separated from the body. They have two dorsal fins and no anal fin. 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 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.
The smoothback angelshark is found on Africa's western coast down to Namibia, as well as in the Mediterranean. It lives in the outer margins of the continental shelf at depths between 20 and 500 meters, although it usually resides in depths above 100 meters.
The data for the biology of this species is limited. It is known to feed on small sharks, bony fish, cephalopods and crabs. Like all angelsharks it is ovoviviparous. The pups are 24–27 centimetres long at birth.
The smoothback angelshark is critically endangered. Like the sawback angelshark (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 sawback angelshark and the angelshark, the Portuguese fisheries authorities in the area off Morocco and Mauritania saw a fall of 95% between 1990 and 1998. The pressure of fisheries on the species distribution is likely to intensify in the future.
A sawshark or saw shark is a member of a shark order bearing a unique long, saw-like rostrum edged with sharp teeth, which they use to slash and disable their prey. There are eight species within the Pristiophoriformes, including the longnose or common sawshark, shortnose sawshark, Japanese sawshark, Bahamas sawshark, sixgill sawshark, African dwarf sawshark, Lana's sawshark and the tropical sawshark.
The angelsharks are a group of sharks in the genus Squatina of the family Squatinidae. They commonly inhabit sandy seabeds close to 150 m (490 ft) in depth. Many species are now classified as critically endangered by the International Union for Conservation of Nature. Once common over large areas of the Northeast Atlantic from Norway, Sweden, Morocco and the Canary Islands, to the Mediterranean and Black Seas, fishing pressure has resulted in significant population decline.
The Izak catshark or simply Izak is a species of catshark, belonging to the family Scyliorhinidae, common off the coasts of South Africa and southern Namibia. It typically inhabits the outer continental shelf at depths of 100–300 m (330–980 ft), with the males found deeper than the females and juveniles. The Izak catshark has a short, wide, flattened head and a robust body tapering to a long, slender tail. It can be identified by its ornate color pattern of dark brown spots or reticulations and blotches on a light yellowish background, as well as by the enlarged dermal denticles over its pectoral fins and along its dorsal midline from the snout to the second dorsal fin. This species reaches 69 cm (27 in) in length, with the males larger than females.
The sand devil or Atlantic angel shark is a species of angelshark, family Squatinidae, native to the northwestern Atlantic Ocean. It occurs off the eastern United States, in the northern Gulf of Mexico, and possibly in parts of the Caribbean Sea. This bottom-dwelling shark is found in shallow inshore waters in summer and fall, and deep offshore waters in winter and spring. The sand devil's flattened body and enlarged pectoral and pelvic fins give it a ray-like appearance. There is a band of enlarged thorns running along the middle of its back. It is gray or brown in color, with scattered small dark spots. This species reaches 1.2–1.5 m (3.9–4.9 ft) in length.
The speckled smooth-hound is a houndshark of the family Triakidae. It is found on the continental shelf of the eastern Pacific, between latitudes 0° and 54° S, at depths between 16 and 50 m. It can reach a length of 130 cm (51 in). Collectively with certain other species of shark, it is known as "tollo".
The peppered catshark is a common but little-known species of catshark, part of the family Scyliorhinidae, inhabiting depths of 130–1,326 m (427–4,350 ft) in the northern Gulf of California. It is found on or near the ocean floor, and conducts seasonal migrations, spending winter in deeper water. Reaching a length of 37 cm (15 in), this species has a slender grayish body with a fine covering of black dots. On the dorsal edge of its caudal fin is a prominent crest of enlarged dermal denticles. It is oviparous, with the reproductive period probably lasting from May to September. The International Union for Conservation of Nature (IUCN) has listed the peppered catshark under Least Concern, as it faces no significant threats from human activity.
The sawback angelshark 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 lives in sandy and muddy bottoms of the ocean at depths of 30-500m.
The eastern angelshark is an angelshark of the family Squatinidae.
The African angelshark is an angelshark of the family Squatinidae.
The Argentine angelshark is an angelshark of the family Squatinidae.
The Australian angelshark is a species of angelshark, family Squatinidae, found in the subtropical waters of southern Australia from Western Australia to New South Wales between latitudes 18°S and 41°S, at depths down to 255 m (840 ft). Its length is up to 1.52 m (5 ft). Reproduction is ovoviviparous, with up to 20 pups in a litter.
The Pacific angelshark is a species of angelshark, family Squatinidae, found in the eastern Pacific Ocean from Alaska to the Gulf of California, and from Ecuador to Chile, although those in the Gulf of California and southeastern Pacific may in fact be separate species. The Pacific angelshark inhabits shallow, coastal waters on sandy flats, usually near rocky reefs, kelp forests, or other underwater features. This species resembles other angel sharks in appearance, with a flattened body and greatly enlarged pectoral and pelvic fins. Characteristic features of this shark include a pair of cone-shaped barbels on its snout, angular pectoral fins, and a brown or gray dorsal coloration with many small dark markings. It attains a maximum length of 1.5 m (4.9 ft).
The Taiwan angelshark is an angelshark in the family Squatinidae. The Taiwan angelshark is one of four species of Squatina in the waters around Taiwan and Japan. It is a demersal, ray-like shark that grows to 1–2 meters in length.
The Japanese angelshark is a species of angelshark, family Squatinidae, found in the northwestern Pacific Ocean off China, Japan, and Korea. It is a bottom-dwelling shark found in sandy habitats down to 300 m (980 ft) deep. This species has the flattened shape with wing-like pectoral and pelvic fins typical of its family, and grows to 1.5 m (4.9 ft) or more in length. Its two dorsal fins are placed behind the pelvic fins, and a row of large thorns occurs along its dorsal midline. Its upper surface is cryptically patterned, with numerous squarish dark spots on a brown background.
Squatina squatina, the angelshark or monkfish, is a species of shark in the family Squatinidae, that were once widespread in the coastal waters of the northeastern Atlantic Ocean. Well-adapted for camouflaging itself on the sea floor, the angelshark has a flattened form with enlarged pectoral and pelvic fins, giving it a superficial resemblance to a ray. This species can be identified by its broad and stout body, conical barbels, thornless back, and grayish or brownish dorsal coloration with a pattern of numerous small light and dark markings. It measures up to 2.4 m (7.9 ft) long.
The Indonesian angelshark is a rare species of angelshark, family Squatinidae, known only from a few specimens collected from fish landing sites in southern Indonesia. It is thought to inhabit the deep waters of the continental slope. Reaching at least 1.34 m (4.4 ft) long, this species has a flattened, ray-like shape and a well-developed tail and caudal fin. It is characterized by the absences of fringes on its nasal barbels and thorns down the midline of its back, as well as by its relatively plain grayish-brown dorsal coloration with dark saddles beneath the dorsal fin bases and a black leading margin on the underside of the pectoral fins. The International Union for Conservation of Nature (IUCN) has classified it as Critically Endangered due to significant fishing pressure.
The Philippines angelshark is a species of angelshark, family Squatinidae, known only from a 33 cm (13 in) long immature female caught in the Philippines, where it is the only known representative of its family. It has a flattened body and head with greatly expanded pectoral and pelvic fins, and is greenish above with brown spots. Identifying traits of this species include the spiracles, which are more widely spaced than the eyes and bear papillae on the posterior inner rims, and the relative positions of the two dorsal fins. Additionally, S. caillieti lacks fringes on its barbels, enlarged thorns along the middle of its back, and ocelli ("eyespots") on its fins.
The disparate angelshark is a species of angelshark. It occurs at depths down to 164 m in the Gulf of Mexico and reaches a length of 49 cm (19 in). Heteroptera in its name refers to the difference in size, shape and area of the two dorsal fins. Disparate angelsharks have the typical angel shark body form that is broadly flattened with large pectoral/pelvic fins and eyes and spiracles on the top of their heads. Their common and species name comes from them having dorsal fins of very different sizes, shapes, and areas compared to other angel sharks.
Squatina mapama is a species of angelshark found in the Caribbean. It was described by Douglas J. Long, David A. Ebert, Jose Tavera, Arturo Acero Pizarro, and David Ross Robertson in December 2021.
Vari's angelshark is an angelshark in the family Squatinidae found in Southwestern Atlantic, specifically Brazil. It lives in the continental slope between latitudes 11° and 22°S, at the depths of 195–666 m (640–2,185 ft).
