Anomioides Kitten’s Paw Shell, Plicatula anomiodes

Anomioides Kitten’s Paw Shell, Plicatula anomiodes. Shell collected off the beach at Punta Chivato, Baja California Sur, April 2026. Size: 3.8 cm (1.5 inches) x 3.0 cm (1.2 inches) x 0.8 cm (0.3 inches). Photograph and Identifications courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Anomioides Kitten’s Paw Shell, Plicatula anomiodes. Shell collected off the beach at Punta Chivato, Baja California Sur, February. Size: 3.5 cm (1.4 inches) x 2.9 cm (1.1 inches) x 0.3 cm (0.1 inches). Photograph and Identifications courtesy of Colin Campbell, DVM, Punta Chivato, Baja California Sur.

Phylogeny: The Anomioides Kitten’s Paw Shell, Plicatula anomioides (Keen, 1958) is a member of the Plicatulidae Family of Kitten Paw Shells. The Plicatula Genus is the only genus in the Plicatulidae Family and there are seventeen species in the Plicatula Genus. The specific name anomioides means that this shell resembles Jingle Shells of the Anomia Genus and refers to the irregular and asymmetrical shape of Jingle Shells.

Description: Anomioides Kitten’s Paw Shells have an irregular round to ovate outline and a compressed profile. The right valve attaches to the substrate which leaves a flattened scar on the shell’s exterior. The left valve is sculpted with moderate, divaricate (widely branching), radial ribs. The interior and exterior are generally whitish or grayish, with green to brownish-green blotches. The exterior is frequently overgrown by encrusting organisms. Anomioides Kitten’s Paw Shells reach a maximum of 4.2 cm (1.6 inches) in diameter.

Habitat and Distribution: Anomioides Kitten’s Paw Shells are found attached to rocks and other hard surfaces. They live in the intertidal zone and to depths up to 29 m (95 feet). They are a subtropical to tropical Eastern Pacific species that are found in all Mexican waters of the Pacific Ocean, with the exception that they are absent from the west coast of the Baja Peninsula.

Ecology and Behavior:  Anomioides Kitten’s Paw Shells are suspension feeders that feed primarily on planktonic algae and suspended organic matter. They are preyed upon by crabs, fish, gastropods, and sea stars. They 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 Anomioides Kitten’s Paw Shells 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: Plicatulostrea anomioides.