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Izak catshark
The Izak catshark (or simply Izak, ''Holohalaelurus regani'') 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 , 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 (in juveniles) or reticulations and blotches (in adults) 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 in length, with the males larger than females.
Bottom-dwelling and perhaps relatively active in nature, the Izak catshark feeds mainly on a diverse array of bony fishes, crustaceans, and cephalopods. A significant portion of its diet may be scavenged from offal discarded by fisheries. This species is oviparous, with females producing encapsulated eggs two at a time year-round. The Izak catshark is regularly caught incidentally by a South African bottom trawl commercial fishery, but is discarded rather than utilized. Despite the fishing pressure, its population has been increasing and thus the International Union for Conservation of Nature (IUCN) has assessed it as Least Concern.
==Taxonomy==
The Izak catshark was originally described by South African ichthyologist John Gilchrist in a 1922 fisheries survey report. He assigned the new species to the genus ''Scylliorhinus'', and gave it the specific epithet ''regani'' in honor of fellow ichthyologist Charles Tate Regan.〔 In 1934, Henry Weed Fowler assigned this species to his newly created ''Holohalaelurus'', a subgenus of ''Halaelurus''. ''Holohalaelurus'' has since been elevated to the rank of full genus.〔 As there do not appear to be any existing type specimens referable to Gilchrist's account, in 2006 Brett Human designated a long male caught in Hondeklip Bay as the species neotype.〔
Historically, there has been much confusion in the scientific literature between ''H. regani'', ''H. punctatus'', and ''H. melanostigma'', the last of which at various times had been considered a junior synonym of ''H. regani'' and was itself confounded with ''H. grennian''. Furthermore, two forms of ''H. regani'' were once recognized: the "Cape" or "typical" form and the "Natal" or "northeastern" form. The latter "northeastern" form was described as a separate species, ''H. favus'', in 2006.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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