Baja Cardita Shell, Carditamera bajaensis
Baja Cardita Shell, Carditamera bajaensis. Shell collected off the beach at Punta Chivato, Baja California Sur, May 2025. Size: 2.8 cm (1.1 inches) x 1.2 cm (0.5 inches) x 0.5 cm (0.29 inches). Collection, photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.
Phylogeny: The Baja Cardita, Carditamera bajaensis (González and Girabet, 2012), is a bivalve mollusk that is a member of the Carditidae Family of Little Heart Shells. The Carditimera Genus is one of thirty-seven genera in the Carditidae Family, and there are eight species in the Carditamera Genus. The name Carditamera comes from the Greek words, which mean “part of Cardita” or “part of little heart”. The specific name bajaensis refers to the Baja California region, from which this species was first described.
Description: Baja Cardita Shells are equivalve, inflated, and have a rounded trapezoidal outline. These shells are about two times as long as they are wide. The anterior is sharply rounded. The posterior is much longer, and truncate (appearing chopped-off) toward the anterior margin. The exterior is sculpted with around 12 strong, rounded, radial ribs. These ribs crossed by irregular commarginal lines, and do not become spinous at the posterior end. The exterior of the shell is whitish, with reddish brown to dark brown sections. The interior is white, with brown to black patches along dorsal margins. They have a dark brown periostracum. Baja Cardita Shells reach a maximum of around 4 cm (1.6 inches) in length. These shells are similar in appearance to the Similar Cardita Shell, Carditamera affinis, and most easily distinguished by habitat; the Baja Cardita is found buried or partially buried in sand, mud, or loose gravel, while the Similar Cardita is found on top of hard substrates or in rock crevasses. Also, the similar Cardita is wider (1.5 times as long as high) and has spinous ribs at the posterior end.
Habitat and Distribution: The Baja Cardita is relatively new to science and there is limit documentation of their location and behavior. Previously gathered data may have been mistakenly attributed to the similar looking Carditamera affinis. Baja Carditas are found buried or partially buried in sand, mud, or loose gravel. They live in the intertidal zone and to an unknown depth. They are a subtropical to tropical Eastern Pacific species that in Mexican waters of the Pacific Ocean are found throughout the Sea of Cortez, at least as far south as Mazatlán, Sinaloa.
Ecology and Behavior: Baja Carditas are suspension feeders that feed primarily on planktonic algae and suspended organic matter. They are prey for shore birds, crabs, and fish. Baja Cardita Shells are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective the Baja Cardita has not been formally evaluated.
Synonyms: None