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''Orthalicus reses'', common name the Stock Island, Florida tree snail, is a species of large tropical air-breathing land snail, a tree snail, a terrestrial pulmonate gastropod mollusk in the family Orthalicidae. It was first described in 1830 by the American naturalist Thomas Say. The holotype, a specimen probably collected in Key West, was subsequently lost. Over a hundred years later, in 1946, the American biologist Henry Augustus Pilsbry redescribed the species using a specimen from Stock Island. ''Orthalicus reses'' has two subspecies, ''O. reses reses'' and ''O. reses nosodryas''. The validity of these two taxa is still being discussed, but some experts argue that considering them as independent units may be important for management purposes. The Stock Island tree snail has a large conical shell (45 - 55 mm in length) with variable thickness, generally lighter and more translucent than other species of ''Orthalicus''. It is colored white to buff, with weakly developed spiral bands and several flame-like, purple-brown axial stripes. The subspecies ''O. reses reses'' and ''O. reses nosodryas'' can be distinguished from one another based on the different color patterns of the apical whorl, columella, and parietal callus. The nominate subspecies ''Orthalicus reses reses'' is threatened; it lives on trees in hardwood hammocks habitat in Southern Florida, USA, specifically the Florida Keys.〔〔 ==Taxonomy== ''Orthalicus reses'' is a species within the genus ''Orthalicus'', a group of large, arboreal pulmonate snails in the family Orthalicidae. The genus ''Orthalicus'' occurs primarily in Central and South America. Two species occur in North America, ''Orthalicus reses'' and ''Orthalicus floridensis'' Pilsbry, both of which are restricted to South Florida. The Stock Island tree snail (''Orthalicus reses'') was first described by Thomas Say in 1830, based on a snail which was probably collected in Key West. That specimen was lost, and the species was later redescribed by Henry Augustus Pilsbry in 1946〔 using a snail collected from Stock Island.〔 ''Orthalicus reses'' has two subspecies:〔 * ''Orthalicus reses reses'' (Say, 1830) - Stock Island tree snail * ''Orthalicus reses nesodryas'' Pilsbry, 1946〔 - Florida Keys treesnail It is generally thought that the two subspecies of ''Orthalicus reses'' do not interbreed due to anatomical incompatibility.〔〔U.S. Fish and Wildlife Service. (1982). Stock Island tree snail recovery plan. U.S. Fish and Wildlife Service; Atlanta, Georgia.〕〔U.S. Fish and Wildlife Service. (1996). Multispecies Recovery Team/Keys Group meeting, April 1996.〕 However, Emmel and Perry (2004)〔 recommended that if the two ''Orthalicus reses'' subspecies prove to be as genetically invariant as was observed in their study, the groups should be considered a single taxon or taxonomic unit. In that case, the nominate form, ''Orthalicus reses reses'', would prevail, and ''Orthalicus reses nesodryas'' would be demoted to a synonym instead of a valid subspecies.〔 Emmel and Perry (2004) however asserted that the taxa “should continue to be considered as independent units for management purposes”.〔 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「Orthalicus reses」の詳細全文を読む スポンサード リンク
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