The Atlantic Mud Piddock
The Atlantic Mud Piddock, Barnea truncata (Say, 1822) is a bivalve that bores into hard clay and soft rock. It will settle as a larva onto the host rock, and will grow as it bores into it. The resulting borehole is conical (with the narrow end toward the rock surface), and the Piddock ends trapped inside the rock for life. The Atlantic Mud Piddock is a close relative of the Angel Wing. Despite its very broad geographical distribution in the Atlantic Ocean (from Canada to Florida, Gulf of Mexico, to Brazil, and West Africa), the species is known to occur in very restricted areas in Southwest Florida. The Canadian population of the Atlantic Mud Piddock is restricted to living in red mudstone in the Minas Basin, in Nova Scotia. That population is separated from the nearest one, in Maine, by a distance of 220 miles. A decline in the population size of the species in Canada (caused by destruction of its red mudstone habitat) has prompted the Committee on the Status of Endangered Wildlife in Canada to consider the species as threatened in that country.
Photos by José H. Leal.