Squatina and other Squatiniformes differ from other sharks in having flattened bodies and broad pectoral fins that give them a strong resemblance to rays.
Restriction in geographic range might be as a result of the behaviour of Squatina species, which are ambush predators with a corresponding stationary bottom-dwelling habit.
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.
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.
[5] Angel sharks possess extensible jaws that can rapidly snap upwards to capture prey and have long, needle-like teeth.
[6] Angel sharks usually reside in depths of 1–200 metres (3.3–656.2 ft) and can be seen on muddy or soft benthic substrata where they can easily blend in as they lie in wait.
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.
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.
In 1977, Michael Wagner, a fish processor in Santa Barbara, California, US, in cooperation with local commercial fishermen, developed the market for angel sharks.
In 1991, the use of gillnets in nearshore state waters of California was forbidden, and fishing was restricted in a larger portion of the Pacific angel shark's range.
[13][14] Angel sharks are highly sensitive to bottom trawling and are often caught in gillnets, due to their shallow habitat range.
Angel sharks found in the Mediterranean Sea, S. aculeata, S. oculata, and S. squatina, are at a high risk of extinction, with geographic studies projecting severe population declines for the three species.
[16] The earliest members of the Squatiniformes are known from the Late Jurassic (from around 160 million years ago) of Europe, assigned to the genus Pseudorhina.