Magdalena Venus Clam Shell, Globivenus magdalenae

Magdalena Venus Clam Shell, Globivenus magdalenae. Shell collected from within the estuary of the Magdalena Bay complex, Baja California Sur, October 2018. Size: 4.9 cm (1.9 inches) x 4.4 cm (1.7 inches). Collection, photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Magdalena Venus Clam, Globivenus magdalenae (Dall, 1902), is a bivalve mollusk that is a member of the Veneridae Family of Venus Clam Shells. The genus Globivenus is one of one hundred seven genera in the Vereridae Family, and there are twenty-one species in this genus. They are known in Mexico as Almeja Venus de Magdalena.

Description: The Magdalena Venus Clam shell has a circular profile and is globose. The exterior has numerous raised concentric ridges. The exterior of the shell white to cream in color with brown streaks or blotches. The interior is white. Magdalena Venus Clam shells reach a maximum of 5.3 cm (2.1 inches) in length and 4.8 cm (1.9 inches) in height.

Habitat and Distribution: Magdalena Venus Clams are found in mud and sand substrates. They live in moderately deep water, at depths between 35 m (115 feet) and 200 m (655 feet). They are a subtropical to tropical Eastern Pacific species that are found in Mexican all waters of the Pacific Ocean with the exception that they are absent from north of Magdalena Bay, Baja California Sur along the central and northwest coasts of the Baja Peninsula and north of Punta Arena, Baja California Sur along the east coast of the Baja Peninsula and north of Bahía San Carlos, Sonora along the west coast of the Baja Peninsula in the Sea of Cortez.

Ecology and Behavior:  Magdalena Venus Clams are suspension feeders that feed primarily on planktonic algae and suspended organic matter. They are gonochoric and reproduce sexually, through broadcast spawning, with external fertilization. There is no mention in the available literature of them engaging in any types of parasitic, commensal, or symbiotic relationships. From a conservation perspective they have not been formally evaluated however they are fairly common with a relatively wide distribution and should be considered to be of Least Concern.

Synonyms: Cytherea (Ventricola) magdalenae and Cytherea magdalenae.