Семейство акул-нянек: разнообразие и особенности

Family of fishes
additional species called "dogfish"
Catsharks are ground sharks of the family Scyliorhinidae. They are the largest family of sharks with around 160 species placed in 17 genera. The family is paraphyletic, containing several distinct lineages that do not form a monophyletic group.

The family includes 17 genera and over 150 species, Sonic hedgehog (a secreted protein that, in humans, is encoded by the SHH gene) is involved in the growth and patterning of different organs. Every 18–38 days the teeth are replaced as is a common characteristic of the developmental process of sharks. The "swell sharks" of the genus Cephaloscyllium have the curious ability to fill their stomachs with water or air when threatened, increasing their girth by a factor of one to three. Some catsharks, such as the chain catshark are biofluorescent.

Catsharks are found around seabeds in temperate and tropical seas worldwide, ranging from very shallow intertidal waters to depths of 2,000 m (6,600 ft) or more, such as the members of genus Apristurus. The red spotted catshark lives in the shallower rocky waters ranging from Peru to Chile and migrates to deeper waters during the winter. They are usually restricted to small ranges. Juvenile and adult chain dogfish live on the soft or rocky bottom of the Atlantic from Massachusetts to Nicaragua. Adults tend to live on the soft, sandy bottoms possibly due to their need of egg deposition sites.

Some catsharks do not undergo long distance migrations because they are poor swimmers. Due to being nocturnal, some species sleep close together in crevices throughout the day and then go hunting at night. Some species of catsharks may deposit egg cases in structured habitats, which may also act as nurseries for the newly hatched sharks. Almost a year is needed for a catshark to hatch from the egg. Instead of laying the eggs and letting them sit for a year, some species of catsharks hold onto the eggs until a few months before the shark hatches. Some catsharks exhibit ovoviviparity, aplacental viviparous, by holding onto the embryos until they are completely developed and then give live birth. Some species of catsharks mate by biting and holding the female’s pectoral fins and wrestle her into a mating position.

The Australian marbled catshark, Atelomycterus macleayi, is a favored type for home aquaria, because it rarely grows to more than in length. The coral catshark, however, is the most common scyliorhinid in home aquaria.