Coffee Bean Shell, Pseudopusula californiana

Coffee Bean Shell, Pseudopusula californiana, Dark Morph. Shell collected off the beach in the greater Punta Chivato area, Punta Chivato, Baja California Sur, February 2023. Size: 8.5 mm (0.3 inches) x 6.0 mm (0.2 inches) x 4.5 mm (0.2 inches) Collection, photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato.

Coffee Bean Shell, Pseudopusula californiana. Shell collected off the beach in the greater Punta Chivato area, Punta Chivato, Baja California Sur, February 2023. Size: 8.5 mm (0.3 inches) x 6.0 mm (0.2 inches) x 4.5 mm (0.2 inches). Collection, photograph and Identification courtesy of Colin Campbell, DVM, Punta Chivato.

Coffee Bean Shell, Pseudopusula californiana . Shell collected off the beach in the greater San Diego area, April 2015. Size: 1.1 cm (0.4 inches) x 0.9 cm (0.4 inches). Collection, photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Coffee Bean, Pseudopusula californiana (Gray, 1828), is a gastropod mollusk that is a member of the Triviidae Family of False Cowries or Trivia Shells. The genus Pseudopusula is one of sixteen genera in this family, and there are fifteen species in this genus. This species is also known as the California Trivia Shell and the Coffee Bean Trivia Shell and in Mexico as Trivia Californiana.

Description: Coffee Bean Shells are small in stature and somewhat egg-shaped in outline. They have twelve strong spiral ribs that cross the shell, stopping and leaving a narrow gap at the top of the dorsal surface. These shells have an internal spire and a curved slit-like aperture that has toothed lips. The exterior of the shell is a dark purplish brown color with a light gray gap. For live animals, their mantle is orangish to yellowish brown, marked with papillae, and covers most of the shell. The Coffee Bean Shell reach a maximum of 1.3 cm (0.5 inches) in length and 0.9 cm (0.4 inches) in height.

The Coffee Bean Shell is very similar to Solander’s Trivia Shell, Trivia solandri (larger in stature with ribs that do not cross the midline).

Coffee Bean Shell, Pusula californiana, on the right, versus Solander’s Trivia Shell, Trivia solandri. Photograph courtesy of Bob Hillis, Irvins, Utah.

Habitat and Distribution: Coffee Beans are found under rocks, in the intertidal zone, and at depths up to 15 m (50 feet).  They are a temperate to tropical Eastern Pacific species that have a limited distribution in Mexican waters of the Pacific Ocean being found in all coastal waters north of Acapulco, Guerrero, however they are absent from the northern parts of the Sea of Cortez.

Ecology and Behavior: Coffee Beans are predators that feed primarily on compound tunicates. They are gonochoric and reproduce sexually. Their engagement in any type of commensal, parasitic, or symbiotic relationship has not been formally documented. From a conservation perspective the Coffee Bean has not been formally evaluated. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: Cypraea californiana, Cypraea californica, Pusula californiana, Pusula californica, Pusula californica loochooensis, Pusula loochooensis, and Trivia californiana.