Gammarus is an amphipod crustacean genus in the family Gammaridae. It contains about 200 described species, with new ones becoming known at a steady rate. They are the typical "scuds" of North America and range widely throughout the Holarctic. A considerable number is also found southwards into the Northern Hemisphere tropics, particularly in Southeast Asia.
This group might not be monophyletic as presently delimited, even after several species h...
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Gammarus is an amphipod crustacean genus in the family Gammaridae. It contains about 200 described species, with new ones becoming known at a steady rate. They are the typical "scuds" of North America and range widely throughout the Holarctic. A considerable number is also found southwards into the Northern Hemisphere tropics, particularly in Southeast Asia.
This group might not be monophyletic as presently delimited, even after several species have been moved to other genera of Gammaridae, or even to other Gammaroidea families like the Pontogammaridae. On the other hand, confirmation of the content of the monophyletically restricted genus is making good progress. The small genus Sinogammarus seems to be specialized local lineages derived from more conventional Gammarus, and hence are today included in that genus.
The biogeography suggests that an Atlantic (North America and Europe), a Northwest Asian and a Southeast Asian area of radiation can roughly be distingushed. At least 1-2...
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