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Anadara transversa
Image courtesy of the World Register of Marine Species (WoRMS), via the Natural History Museum, Rotterdam through the Creative Commons CC BY-NC-SA 3.0 License.
Anadara transversa
Taxonomic Group: Mollusks-Bivalves


Anadara transversa, commonly known as the Transverse Ark, is a marine bivalve with a thick, strongly ribbed shell. It is native to the Northwest Atlantic, from Cape Cod to Texas and has been introduced to the Aegean and Adriatic Seas. In Western North America, dead, worn shells were found on Atlantic oyster beds in San Francisco Bay, but no live specimens have been found. This species lives on shallow, sandy bottoms and can occasionally attach to rocks and shells. In the Adriatic Sea, the abundance of A. transversa has increased rapidly and it may compete with native species and affect the movement and habitat use of other snails and bivalves.

*Beyond its native range, this species is not established in North America.

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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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