Pustulose Ark Shell, Mule’s Hoof Shell
Pata de Mula, Concha Negra, Arca Negra, Piangua
(Anadara tuberculosa)

Pustulose Ark Shell, Anadara tuberculosa: The Pustulose Ark Shell is large, thick, white, and ovate with 33 to 37 ribs. There are nodes on the ribs primarily on the anterior end.

They inhabit the mangrove estuaries of the Pacific Coast from Baja California Sur to northern Peru.

They are the most important commercially harvested mollusk along this coastline and an important food source in Central America.

They are easily collected by hand at low tides found in muddy bottoms around mangrove roots, sold for $0.05 each in local markets, and consumed as a component of ceviche.

They range in size to 7.5 cm (3.0 inches). The shells are slow growing taking up to 25 years to reach maximum size, have life spans of 20 to 30 years and are currently an endangered species facing extinction due to overfishing. They are sold via an internet trade but command very low prices.

The Pustulose Ark Shell is a large sized member of the Arcidae Family, which are known as the Mangrove Cockles. They are marine bivalve mollusks with the family have 200 global species. They receive their name because of a large flat area in front of the boss of the shield, a deck, with the rest of the shell illustrating an ancient wooden boat such as Noah’s ark. The shells are trapezoidal in outline with regular radial sculpture, valves tightly closing without a byssal gape. They have hinge teeth in a continuous series of uniform size.

Pustulose Ark Shell picture

Pustulose Ark Shell picture

Pustulose Ark Shell, Anadara tuberculosa: Provided by the commercial fishermen of the greater Los Cabos area, Baja California, Mexico, in May 2011. Size 7.5 cm (3.0 inches) x 4.7 cm (1.9 inches). Description and photos courtesy of John Snow.