Amathusia Venus Clam Shell, Chionopsis amathusia
Amathusia Venus Clam Shell, Chionopsis amathusia. Shell collected off the beach at Punta Chivato, Baja California Sur, May 2022. Size: 5.4 cm (2.1 inches) x 5.1 cm (2.0 inches) x 2.3 cm (0.9 inches). Collection, photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.
Phylogeny: The Amathusia Venus Clam, Chionoipsis amathusia (R. A. Philippi, 1844), is a bivalve mollusk that is a member of the Veneridae Family of Venus Clams. The genus Chionopsis is one of one hundred and seven genera in this family, and there are twelve species in this genus. This species is known in Mexico as almeja.
Description: The Amathusia Venus Clam shell is strong, inflated, and sturdily-built. The exterior of the shell has fine sculpture with inter-ribs between the primarily radial ribs with concentric lamellae raised into prickly scales. The exterior is light brown; the interior is off-white. They are covered with a light-brown thin, velvety periostracum. Amathusia Venus Clam shells reach 7.4 cm (2.9 inches) in length, 6.3 cm (2.5 inches) in height.
Habitat and Distribution: Amathusia Venus Clam shells reside in sand substrate, intertidally, and to depths of 75 m (250 feet). The majority of shells are collected as beach wash-ups. They are a tropical Eastern Pacific species. In Mexican waters they are found throughout the Gulf of California and along the west coast of the mainland south to Guatemala.
Ecology and Behavior: Amathusia Venus Clams are suspension feeders, which feed on plankton and suspended organic matter. They are prey for fish, crabs, shore birds and gastropods. Amathusia Venus Clams are gonochoric and reproduce sexually, through broadcast spawning. There is no mention in the available literature of them engaging in any types of parasitic, commensal, or symbiotic relationships. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be consider to be of Least Concern.
Synonyms: Chione jamaniana, Venus anathusia and Venus darwinii.