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Southern torrent salamander
The southern torrent salamander (''Rhyacotriton variegatus'') is a member of the Rhyacotritonidae family of salamanders. This species of torrent salamander is found the farthest south in the region. It is a small salamander endemic to the Pacific Northwest from Northern California to Northern Oregon. It is one of four species of ''Rhyacotriton'', along with ''R. cascadae'', ''R. kezeri'' and ''R. olympicus''. All species of Rhyacotriton are small, with their body lengths being less than 5 inches. The species reproduces annually, with an extended courtship and egg-laying period.〔 The time it takes from oviposition to reach sexual maturity ranges from five to eight years, making the generation interval rather long.〔 The larval stage, from hatching to metamorphosis, lasts 2.0-2.5 yr, with females requiring another 1.5–2.0 yr until they can first breed.〔 They reach sexual maturity 1.0-1.5 yr after metamorphosis which occurs between 4.5 and 5.0 yr. This species feeds on small insects and spiders. Although it is found over a large area, it is not a migratory creature. It is preyed on by Pacific giant salamanders and garter snakes.
==Identification==
The species in the ''Rhyacotriton'' genus are all similar in morphology, but have high genetic diversity. ''R. variegatus'' lives in aquatic environments from egg through metamorphic stages. Through adulthood individuals live on the waters edge among pebbles and rocks. ''R. variegatus'' has the lowest desiccation tolerance of all North American salamanders, meaning they cannot easily withstand “extreme” temperatures and low moisture levels.〔 The habitats preferred by ''R. variegatus'' are cool, shallow, high in oxygen, and slow-flowing, such as seeps and mountain brooks, with coarse, gravel-like beds. These water sources are found mostly in forests, which is where ''R. variegatus'' is most often found.〔 All species of ''Rhyacotriton'' have aquatic eggs and larvae, and adults are semi-aquatic. ''R. variegatus'' adults can venture away from the stream, but they prefer the water, only coming out when the moisture level of the ground is high enough.〔 Adults and juveniles are subject to moisture loss as well as heat shock.〔
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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