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Gammarus

Genus of crustaceans

Wikipedia contributorsAdapted for Fathomly · View authors
6 min read
Source updated May 18, 2026
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Gammarus is an amphipod crustacean genus in the family Gammaridae. It contains more than 200 described species, making it one of the most species-rich genera of crustaceans. Different species have different optimal conditions, particularly in terms of salinity, and different tolerances; Gammarus pulex, for instance, is a purely freshwater species, while Gammarus locusta is estuarine, only living where the salinity is greater than 25‰.

Species of Gammarus are the typical "scuds" of North America and range widely throughout the Holarctic. A considerable number are also found southwards into the Northern Hemisphere tropics, particularly in Southeast Asia.

01Species

The following species are included: Four new species were found in 2018 on the Tibetan Plateau. Four more new species were described from the Chihuahuan Desert in 2021.

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This article is adapted from the Wikipedia article “Gammarus”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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