Uber Milk Moon Shell, Polinices uber

Uber Milk Moon Shell, Polinices uber. Size: 4.1 cm (1.6 inches) x 3.4 cm (1.3 inches). Shell collected off the beach of Bahía Concepción, Baja California Sur, July 2005. Collection, photograph and identification courtesy of Bob Hillis, Ivins, Utah.

Phylogeny: The Uber Milk Moon Shell, Polinices uber (Valenciennes, 1832), is a gastropod mollusk that is a member of the Naticidae Family of Moon Shells. The genus Polinices is one of thirty-eight genera in this family, and there are forty-one species in this genus. They are also known as the  Pacific Moonsnail Shell and in Mexico as Caracol Lunar del Pacífico.

Description: The Uber Milk Moon Shell has a large and, compared to other moon shells, elongated body whorl. They have a fairly high, pointy,  spire. The exterior of the shell has a smooth surface except for growth lines. The exterior may be white, yellowish, cream or beige in color, often with orange-brown staining. The aperture is semi-circular with a wide inner lip at the top, which partially covers the umbilicus. The interior of the shell is white and shiny. Uber Milk Moon Shells reach a maximum of 5.5 cm (2.2 inches) in length and 4.6 cm (1.8 inches) in height.

Habitat and Distribution: Uber Milk Moons are found on mud and muddy sand substrates from the intertidal zone to depths up to 91 m (300 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 north of Scammon’s Lagoon, Baja California, along the central and northwest coasts of the Baja Peninsula.

Ecology and Behavior: Uber Milk Moons are predators that feed primarily on shelled mollusks. They are gonochoric and reproduce sexually, with internal fertilization.  The eggs are laid in a “sand collar”. 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 consider to be of Least Concern.

Synonyms:  Natica ovum, Natica uber, and Natica virginea.