(Squatinidae)
Angel Sharks
Акулоангелові
Squatiniformes is an order of sharks belonging to Squalomorphi. It contains only a single living genus Squatina, commonly known as angelsharks. They commonly inhabit sandy seabeds close to 150 m in depth. Squatina and other Squatiniformes differ from other sharks in having flattened bodies and broad pectoral fins that give them a strong resemblance to rays. They occur worldwide in temperate and tropical seas. Most species inhabit shallow temperate or tropical seas, but a few species inhabit deeper water, down to 1,300 m.
Appearance and biology
Angel sharks grow up to 2.1 m and can weigh around 35 kg. While the anterior part of the angel shark’s body is broad and flattened, the posterior part retains a muscular appearance more typical of other sharks. The eyes and spiracles are dorsal and the five gill slits are on its back. Both the pectoral and pelvic fins are large and held horizontally. There are two dorsal fins, no anal fin and unusually for sharks, the lower lobe of the caudal fin is longer than the upper lobe. Some angel sharks have deformities that have been described in elasmobranchs. These can include skeletal deformities, as lateral spinal curvature (scoliosis), humpback curvature (khyphosis), axial spinal curvature (lordosis), missing fins, additional fins, deformed snout, and more. These abnormalities have only been found in a few sharks, but the causes of these deformities have been found to be from dietary nutritional imbalance, genetic factors, parasites, traumatic injuries, or stress in the specimen.
Spinal scoliosis has been reported to be diverse in sharks, but mostly in pelagic sharks that depend on their swimming abilities to catch their prey. For the angel shark, specifically S. squatina, these curvatures do not seem to significantly affect its hunting capacity, which involves burying itself to ambush their prey. Right now, research is assuming most physical injuries are caused by human interactions because of the constant interference in coastal areas, where most of the sharks reside. There have been few attacks reported, and what few have occurred were due to accidental stepping on of buried newborn sharks.
Angel sharks possess extensible jaws that can rapidly snap upwards to capture prey and have long, needle-like teeth. They bury themselves in loose sediment lying in wait for prey, which includes fish, crustaceans and various types of mollusks. They are ovoviviparous, producing litters of up to 13 pups. Pacific angel shark pups are born from March to June in deep water; generally 180 to 300 feet; possibly to protect the pups from predators.
Angel sharks usually reside in depths of 1–200 m and can be seen on muddy or soft benthic substrata where they can easily blend in as they lie in wait. Members of the family Squatinidae have a unique camouflage method, which relates to how they obtain their food, involving lying still on the sea floor, making rapid lunges at passing prey, and using negative pressure to capture prey by sucking it into their mouths.
Habitat
Angel sharks inhabit temperate and tropical marine environments. They are generally found in shallow waters at depths from 3–100 m off coasts. They are known to bury themselves in sandy or muddy environments during the day, where they remain camouflaged for weeks until a desirable prey crosses paths with them. At night, they take a more active approach and cruise on the bottom of the floor. Squatina preys on fish, crustaceans, and cephalopods.
Behavior
Although this shark is a bottom-dweller and appears harmless, it can inflict painful lacerations if provoked, due to its powerful jaws and sharp teeth. It may bite if a diver approaches the head or grabs the tail.
Angelsharks have a unique way of breathing compared to most other benthic fish. They do not pump out water from the oropharyngeal cavity like other fish. Instead they use gill flaps located under their body to pump out water during respiration. Doing so also allows them to be more discreet and prevent detection.
(Squatina squatina)
Common Angelshark
Акула-ангел європейська
It occurs in the temperate waters of the northeastern Atlantic, from southern Norway and Sweden to the Western Sahara and the Canary Islands, including around Ireland and Britain and in the Mediterranean, at depths of up to 150 m.
(Squatina japonica)
Japanese Angelshark
Акула-янгол японська
It is found in the north-western Pacific off China, Japan, and Korea. It is a bottom-dwelling shark that inhabits sandy habitats at depths of up to 300 m.
(Squatina californica)
Pacific Angelshark
Акула-янгол тихоокеанська
It is found in the eastern Pacific Ocean from Alaska to the Gulf of California, and from Ecuador to Chile, at depths of 3–205 m.
(Squatina australis)
Australian Angelshark
Акула-янгол австралійська
It is 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.
(Squatina aculeata)
Sawback Angelshark
Акула-янгол колюча
It is found in the eastern Atlantic off Senegal, The Gambia, and Sierra Leone. In the Mediterranean Sea, it occurs along the southern coast from Algeria to the eastern basin, and along the northern coast from Turkey, possibly to Albania. It inhabits depths of 30–500 m.
(Squatina africana)
African Angelshark
Акула-янгол африканська
It is found in the Western Indian Ocean, primarily along the eastern coast of Africa, from South Africa to Tanzania and out to Madagascar, though possibly extending as far North as Somalia. It inhabits depths of 60–494 m.
(Squatina albipunctata)
Eastern Australian Angelshark
Білоплямиста акула-янгол
It is found off eastern Australia, from Cairns, Queensland, to Lakes Entrance, Victoria, at depths of 37–415 m.
(Squatina argentina)
Argentine Angelshark
Акула-янгол аргентинська
It is found in the south-western Atlantic, from southern Brazil southward to Patagonia, at depths of 50–400 m.
(Squatina armata)
Chilean Angelshark
Акула-янгол чилійська
It is found in the eastern Pacific, from the coast of Ecuador to southern Chile.
(Squatina caillieti)
Philippines Angelshark
Акула-янгол філіппінська
It is found off Philippines, at depths of 363–385 m.
(Squatina david)
David's Angelshark
Акула-ангел Давида
It inhabits the northern coast of South America from Colombia to Suriname and is currently known from a depth between 100 and 150 m.
(Squatina dumeril)
Atlantic Angelshark
Акула-янгол американська
It is found in the northwestern Atlantic Ocean from Massachusetts to the Florida Keys, it also occurs in the northern Gulf of Mexico, and there are additional unconfirmed records from Cuba, Jamaica, Nicaragua, and Venezuela, at depths of 51–272 m.
(Squatina formosa)
Taiwan Angelshark
Акула-янгол тайванська
It is found in the waters around Taiwan and Japan, at depths of 183–220 m, occasionally in shallower waters.
(Squatina guggenheim)
Angular Angelshark
Акула-янгол Гуггенгайма
It is found in the south-western Atlantic, off Brazil, Uruguay, and Argentina, inhabiting marine, brackish, and demersal environments at depths of 4–360 m.
(Squatina leae)
Lea's Angel Shark
Акула-янгол Леї
It is distributed in the western Indian Ocean. It is known from three specimens collected on the Saya de Malha Bank of the Mascarene Plateau at depths of 100–500 m.
(Squatina legnota)
Indonesian Angelshark
Акула-янгол індонезійська
It is found in southern Indonesia, off Palabuhanratu in West Java, Cilacap in Central Java, Kedonganan in Bali, and Tanjung Luar in Lombok.
(Squatina mapama)
Small-crested Angelshark
It is only known by its type specimens, which were collected off the western Caribbean coast of Panama at depths of 1,190–1,259 m.
(Squatina nebulosa)
Clouded Angelshark
Акула-янгол димчаста
It is found in the northwest Pacific from the south-eastern Sea of Japan to Taiwan between latitudes 47° N and 22° N, at depths of 0–200 m.
(Squatina occulta)
Hidden Angelshark
Акула-янгол потайна
It inhabits the Atlantic coastline of South America from southern Brazil to northern Argentina.
(Squatina oculata)
Smoothback Angelshark
Акула-янгол оката
It 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 of 20–500 m.
(Squatina pseudocellata)
Western Australian Angelshark
Акула-янгол західна
It is found on the tropical outer continental shelf off northern Western Australia, at depths of 150–312 m.
(Squatina tergocellata)
Ornate Angelshark
Акула-янгол витончена
It is endemic to southern Australia between latitudes 30°S and 35°S, at depths of 130–400 m.
(Squatina tergocellatoides)
Ocellated Angelshark
Акула-янгол Денді
It is found only from the Taiwan Straits in the western Pacific between latitudes 28 and 22°N.
(Squatina varii)
Vari's Angel Shark
Акула-ангел Варі
It is found in the south-western Atlantic, specifically off Brazil. It inhabits the continental slope between 11° and 22°S, at depths of 195–666 m.
