California freshwater shrimp
| Syncaris pacifica | |
|---|---|
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Infraorder: | Caridea |
| Family: | Atyidae |
| Genus: | Syncaris |
| Species: | S.pacifica |
| Binomial name | |
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Syncaris pacifica Holmes, 1895 |
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Syncaris pacifica is an endangered species of freshwater shrimp in the family Atyidae that occurs only in a limited range within the northern San Francisco Bay Area, California, USA. Specifically, this species occurs only in 17 stream segments within Sonoma, Napa and Marin Counties. This species is often translucent to transparent, with both sexes capable of considerable coloration altering, as a sophisticated form of camouflage. This decapod is commonly known as California freshwater shrimp, and is the only decapod shrimp in California that occurs in non-saline waters.
S. pacifica is one of only four members of the family Atyidae in North America. Genetic studies have been conducted to compare specimens of Syncaris pacifica from various drainages, with the results showing a variety of well-defined genetic variations within these populations. The species has a superficial appearance to its better known marine relatives, and may attain a body length of about 5 cm.
Syncaris pacifica is a ten-legged crustacean that employs a two-pronged approach to camouflage: it uses a technique of translucency coupled with strategically placed chromatophores, which occur internally as well as on the surface. As a result, the clustered color-producing cells combined with translucency masks the body outline and blends the organism to its subsurface environment. Consequently, an illusion is presented that S. pacifica are submerged, decaying vegetation. California freshwater shrimp move quite torpidly and are practically invisible among water column leaf and twig substrates, and among the slender, exposed, living roots of riparian vegetation along undercut stream banks.
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Wikipedia