About Aulacomya atra (Molina, 1782)
Aulacomya atra, also commonly called the Magellan mussel or the ribbed mussel, is a southern species of edible saltwater mussel. It is a marine bivalve mollusk that belongs to Mytilidae, the family of true mussels. Note that the common name "ribbed mussel" is also used for Geukensia demissa, a mussel species native to the Northern Hemisphere. Aulacomya atra is native to South America, where it occurs in Peru, Chile, the Falkland Islands, and Argentina. In Chile, this species grows up to 170 mm in length. It is also found along the coasts of New Zealand and southern Africa, ranging from Namibia to Port Alfred, South Africa. It occurs from the intertidal zone down to a depth of 40 meters. Introduced individual specimens have been recorded in Moray Firth, Scotland. In Southern Africa, the species grows to a maximum length of 90 mm. It typically inhabits dense, crowded intertidal beds. Individual Aulacomya atra have brown ribbed shells, which darken to black as the animal ages.
