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The leopard shark (''Triakis semifasciata'') is a species of houndshark, in the family Triakidae. It is found along the Pacific coast of North America, from the U.S. state of Oregon to Mazatlán in Mexico. Typically measuring 1.2–1.5 m (3.9–4.9 ft) long, this slender-bodied shark is immediately identifiable by the striking pattern of black saddle-like markings and large spots over its back, from which it derives its common name. Large schools of leopard sharks are a common sight in bays and estuaries, swimming over sandy or muddy flats or rock-strewn areas near kelp beds and reefs. They are most common near the coast, in water less than 4 m (13 ft) deep. Active-swimming predators, groups of leopard sharks often follow the tide onto intertidal mudflats to forage for food, mainly clams, spoon worms, crabs, shrimp, bony fish, and fish eggs. Most leopard sharks tend to remain within a particular area rather than undertaking long movements elsewhere, which has led to genetic divergence between populations of sharks living in different regions. This species is aplacental viviparous, meaning that the young hatch inside the uterus and are nourished by yolk. From March to June, the female gives birth to as many as 37 young after a gestation period of 10–12 months. It is relatively slow-growing and takes many years to mature. Harmless to humans, the leopard shark is caught by commercial and recreational fisheries for food and the aquarium trade. This species is mostly fished in the waters off California where, after a period of population decline in the 1980s, new fishing regulations in the early 1990s reduced harvesting to sustainable levels. The International Union for Conservation of Nature has assessed this species as of Least Concern, while noting that local stocks may easily become overfished because of the shark's slow growth and limited migratory habits. ==Taxonomy and phylogeny== The first scientific name applied to the leopard shark was ''Triakis californica'', coined by British zoologist John Edward Gray in the 1851 ''List of the specimens of fish in the collection of the British Museum''. However, Gray did not furnish the name with a proper description, rendering it a ''nomen nudum''.〔 In December 1854, American ichthyologist William Orville Ayres gave a lecture describing the species as ''Mustelis felis'', which included the first scientific description of the species. His lecture was reprinted first in ''The Pacific'', a San Francisco newspaper, and then in the journal ''Proceedings of the California Academy of Natural Sciences''. In April 1855, French biologist Charles Frédéric Girard published another description of this species, naming it ''Triakis semifasciata''. Despite ''M. felis'' being the senior synonym, an error in recording the dates of publication resulted in the widespread use of ''T. semifasciata'' as the leopard shark's scientific name. As a result of this long-standing error, ''Triakis semifasciata'' came to be recognized as the valid name (as a ''nomen protectum'') and ''Mustelis felis'' was invalidated (as a ''nomen oblitum'').〔 The specific epithet ''semifasciata'' comes from the Latin words ''semi'' ("half") and ''fasciatus'' ("banded"), describing this shark's dorsal pattern of saddle-like markings. In older literature, this species may be referred to as "tiger shark" or "catshark". }} |2=''Triakis megalopterus'' + ''Scylliogaleus'' + ''Mustelus'' }} }} }} The genus ''Triakis'' contains two subgenera, ''Triakis'' and ''Cazon''. The leopard shark is placed within the subgenus ''Triakis'' along with the banded houndshark (''T. (Triakis) scyllium''). A 2006 phylogenetic analysis by J. Andrés López and colleagues, based on protein-coding genes, revealed that ''Triakis'' and ''Cazon'' are in fact not closely related, and additionally that the leopard shark may be the most basal member of its family. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「leopard shark」の詳細全文を読む スポンサード リンク
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