Many-ribbed Ark, Larkinia multicostata
Add Photos #5 and #6
Many-ribbed Ark Shell, Larkinia multicostatus. Shell collected off the beach at Punta Chivato, Baja California Sur, March 2022. Size: 6.4 cm (2.5 inches) x 7.3 cm (2.9 inches) x 3.1 cm (1.3 inches). Rib Count: 34. Photographs and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.
Add Photos #3, #4 and #5
Many-ribbed Ark Shell, Larkinia multicostatus. Shell collected off the beach at Punta Chivato, Baja California Sur, December 2021. Size: 9.1 cm (3.6 inches) x 8.4 cm (3.3 inches) x 3.7 cm (1.5 inches). Rib Count: 34. Photographs and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.
The Many-ribbed Ark, Larkinia multicostatus (G.B. Sowerby I, 1833), is an Ark Shell of the Arcidae Family, that is known in Mexico as arca piangua. It is a large heavy and inflated shell that is somewhat square in outline with a prominent beak. The outside is sculpted with 31 to 36 smooth radial ribs. The shell is white, but the outside is covered by a thick dark brown periostracum. The Many-ribbed Ark shells reaches a maximum of 12.5 cm (4.8 inches) in length.
Many-ribbed Arks live in sand and mud habitats, intertidally to depths of 79 m (260 feet). They are found in all Mexican waters of the Pacific Ocean ranging from Southern California to Ecuador, including the Galapagos Islands and throughout the Sea of Cortez.
Synonyms include Anadara multicostata, Arca multicostata, Arca brandtii, and Arca comoluensis.