Panama Harp Shell, Harpa crenata

Panama Harp Shell, Harpa crenata. Shell provided by the commercial fishermen of the greater Los Cabos area, June 2012. Size: 7.8 cm (3.1 inches) x 4.6 cm (1.8 inches).

Phylogeny: The Panama Harp Shell, Harpa crenata (Swainson, 1822), is a gastropod mollusk that is a member of the Harpidae Family of Harp Shells. The genus Harpa is one of three genera in this family, and there are fourteen species in this genus. They are also known as the Crenate Harp Shell and in Mexico as Arpa Crenífera.

Description: Panama Harp Shells have a short, but pointed spire, with flattened axial ribs that often extend as short spines at the shoulder, and onto to spire. The aperture is large, with a siphon notch rather than a canal. The columella is smooth. The exterior of these shells is semi-glossy and may be mottled beige, gray or tan in color, with lavender or dark brown chevrons and blotches. The Panama Harp Shells reach a maximum of 10.0 cm (3.9 inches) in length and 5.8 cm (2.3 inches) in height.

Habitat and Distribution: Panama Harp Shells live on and within sandy substrates at depths between 10 m (35 feet) and 120 m (400 feet). They are a subtropical to tropical Eastern Pacific species that are found in Mexican waters of the Pacific Ocean from Magdalena Bay, Baja California Sur south to Guatemala. They are found south of Bahía San Carlos, Sonora in the Sea of Cortez.

Ecology and Behavior: Panama Harp Shells are a poorly studied and understood species. There is very limited documentation of their diet, predation, reproduction or ecosystem interactions. Other species in Family Harpidae are predators that feed primarily on crabs and shrimp. They are simultaneous hermaphrodites that reproduce sexually through internal fertilization. Mating is indirect. During mating two individuals come together and exchange sperm packets, which are then used to fertilize their eggs.  There is no mention in the available literature of them engaging in any types of parasitic, commensal, or symbiotic relationships. From a conservation perspective the IUCN considers Panama Harp Shells to be a species of Least Concern.

Synonyms: Harpa rivoliana.