About Abra aequalis (Say, 1822)
Abra aequalis (Say, 1822) is a small species with plain, white, mostly smooth shells. Its shells are slightly rounded but triangular in outline, and they are quite thin and fragile. Fully grown individuals reach a size of about 7 millimetres (0.28 inches). Because of its small size and unremarkable appearance that matches several similar species, amateur shell collectors affectionately group this species with others commonly called "little white clams". In 19th century summaries of the species by Robert Parr Whitfield, he described it as "a very neat and pretty shell, and moderately abundant". This bivalve occurs along the southeastern coast of the United States, the Gulf of Mexico, the Caribbean Sea, and the coast of southeastern Brazil. Observation records from the Global Biodiversity Information Facility document occurrences of the species as far north as Long Island. It is abundant along the U.S. coast around Florida, and also occurs around Mexico, the Caribbean Islands, the coasts of Venezuela, Suriname, Panama, and along the Brazilian coast from São Paulo to Pelotas. Abra aequalis usually lives in shallow waters less than 73 metres (240 feet) deep, and has also been observed living on seamounts and underwater knolls. A 1973 study conducted off Sapelo Island, United States, found that A. aequalis becomes the locally dominant species during spring. In Florida, this species is the most significant food source for the starfish Luidia senegalensis.
