Arctica islandica

The Arctica islandica clam belongs to the Arcticidae family, a group of bivalve molluscs that includes many fossil species and just a recent one, the Arctica islandica, that mainly lives in the North Atlantic Ocean.

Morphological features of Arctica islandica

Reaching up to 13 cm in length, this clam has a robust shell with a variable shape, typically oval or round. The umbo is positioned toward the anterior half of the shell and points forward. The valves are very peculiar and have three strong cardinal teeth and one lateral tooth and a clearly visible pallial line, but no pallial sinus. It also has numerous fine concentric growth lines visible on the valves. The external coloration ranges from a mix of light and dark tones to uniformly dark shades. The interior of the shell is whitish.

Distribution of Arctica islandica

Regarding the diffusion of this clam, it’s primarily found in the Atlantic Ocean:

• eastern range: from Iceland and Norway down to France, particularly the Bay of Biscay;
• western range: from Labrador to North Carolina.

The oldest mollusk: the peculiar story of Ming the Clam

Researchers from Bangor University’s School of Ocean Sciences discovered what is considered the world’s oldest living animal: a specimen of Arctica islandica nicknamed Ming, after the Chinese dynasty in power at the time of its birth. Ming lived for over 500 years: in 1499 was born a mollusk that would stay in history, the oldest known individual animal ever recorded.

But how did it live so long? It’s largely due to the unique genetics of the species , which allow it to live for centuries. Scientists determine the clam’s age through radiocarbon dating and by counting growth rings on the shell, each ring marking a year of life. These rings can also be analyzed for oxygen isotopes: thanks to this is possible to track down the climate changes the clam experienced during its lifetime.