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Transorchestia enigmatica
Image courtesy of Ken-ichi Ueda through and the CC BY-NC 2.0 License
Transorchestia enigmatica
Taxonomic Group: Crustaceans-Amphipods


Transorchestia enigmatica is a semi-terrestrial estuarine amphipod commonly known as a beach-hopper. This species is known only from the tidal lagoon of Lake Merritt, California, near San Francisco Bay. However, other members of the genus Transorchestia occur in Chile, Australia and New Zealand and it is presumed to have originated in the Southern Hemisphere. It was found amongst shore debris and is now confined to a muddy-sandy beach within the lagoon. It may have been introduced by sailing ships from Chile or New Zealand, but further taxonomic and genetic investigation is needed.

* Content for this species is based on the literature and peer review is pending - if you have comments or feedback please contact Paul Fofonoff at

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Fofonoff PW, Ruiz GM, Steves B, Simkanin C, & Carlton JT (2018)
National Exotic Marine and Estuarine Species Information System.
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Marine Invasions Lab
Smithsonian Environmental Research Center

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