Lone eroded mussel in a rock crevice. Hondeklipbaai, Northern Cape (2020) - iNaturalist Easily recognised by the strong wavy ridges running the length of the shell. Shell brown in juvenile, but becomes blue-black in larger individuals. Eroded areas are white. Up to 90 mm. Forms extensive beds low in the intertidal and on rocky reefs… Continue reading Ribbed mussel (Aulacomya atra)