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Port Jackson shark
The Port Jackson shark (''Heterodontus portusjacksoni'') is a nocturnal, oviparous (egg laying) type of bullhead shark of the family Heterodontidae, found in the coastal region of southern Australia, including the waters off Port Jackson. It has a large, blunt head with prominent forehead ridges and dark brown harness-like markings on a lighter grey-brown body, and can grow up to long.
The Port Jackson shark is a migratory species, traveling south in the summer and returning north to breed in the winter months. It feeds on hard-shelled mollusks, crustaceans, sea urchins, and fish. Identification of this species is very easy due to the pattern of harness-like markings which cross the eyes, run along the back to the first dorsal fin, then cross the side of the body, in addition to the spine in front of both dorsal fins.
==Distribution and habitat==
The Port Jackson shark is endemic to the temperate waters around southern Australia and can be found in an area stretching from southern Queensland, south to Tasmania, and west to the central coast of Western Australia. There are dubious reports of catchings as far north as Western Australia's York Sound and, on one occasion, it has occurred off the coast of New Zealand. Genetic studies suggest there may be two Australian groups, one found from Northeastern Victoria to Western Australia and the second found from Southern Queensland to New South Wales. The species is believed to have originated somewhere off the coast of South Africa.〔Burton, p. 2027.〕 It usually lives less than of water, but has been known to go as deep as .
The shark's territory is habitually sited on, or near, the sea bottom, which is also its feeding area.〔Dianne J. Bray, 2011, Port Jackson Shark, Heterodontus portusjacksoni, in Fishes of Australia, accessed 26 Aug 2014, http://www.fishesofaustralia.net.au/home/species/1982〕 Rocky environments are the most common habitat, though sandy and muddy ones, as well as seagrass beds, are sometimes used.〔 During the day, when it is usually not active, it can be found in flat areas which offer some shelter from currents (including caves) or near other sheltering positions such as rocky outcrops.
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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