Volcano Keyhole Limpet Shell, Fissurella volcano

Volcano Keyhole Limpet Shell, Fissurella volcano. Shell collected off the beach in the greater Los Cabos area, Baja California Sur, March 2019. Size: 2.5 cm (1.0 inch) x 1.4 cm (0.6 inches). Collection, photograph and identification courtesy Bob Hillis, Ivins, Utah.

Phylogeny: The Volcano Keyhole Limpet Shell, Fissurella volcano (Reeve, 1849), is a gastropod mollusk that is a member of the Fissurellidae Family of Keyhole Limpets. The genus Fissurella is one of forty-five genera in this family, and there are fifty-five species in this genus. They are known in Mexico as Lapa Volcán.

Description: The Volcano Keyhole Limpet Shell has an ovate outline that tapers at the anterior end. They have a high conical profile. The keyhole is just forward of center. They are sculpted with radial ribs, which vary from strong to fairly low. The ribs do not extend over the margin. Most individuals are eroded around the apex. The exterior surface of the shell is pink in color with red to black radial lines. The interior is white to very pale green, with pink around the keyhole. Volcano Keyhole Limpet Shells reach a maximum of 3.5 cm (1.4 inches) in length and 2.1 (0.8 inches) in height.

Habitat and Distribution: Volcano Keyhole Limpets are found attached to rocks in the intertidal zone. They are a subtropical Eastern Pacific species  that are found in Mexican waters of the Pacific Ocean on a limited basis being found north of Magdalena Bay, Baja California Sur, along the central and northwest coasts of the Baja Peninsula.

Ecology and Behavior: Volcano Keyhole Limpets are herbivorous grazers that feed primarily on algae. 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. They have not been formally evaluated from a conservation perspective. However, they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: None