Americoliva venulata (Lamarck, 1811)

Distribution: Temperate Northern Pacific realm, Warm Temperate Northeast Pacific province. Magdalena Transition ecoregion. Cortezian ecoregion. Tropical Eastern Pacific realm. Tropical East Pacific province. Entire Sea of Cortez, Pacic coastline of Baja California Sur, Mexico, at least to Bahia Magdalena and Pacific coastline of Mexico at least to Oaxaca.

Recently Perini (2013) presented a comparative study of 18 populations of this species (as Oliva spicata), one at the Pacific side of Baja California peninsula, fourteen at the Sea of Cortez side of the peninsula and three at the mainland side of the Sea of Cortez. Perini stated: "With the exclusion of the estuary of the Colorado River, north of San Felipe, it was observed that the coasts of the peninsula, like those of many islands, are made up of an alternation of beaches and cliffs. The latter keep the habitats occupied by Oliva spicata separated, and cause a fragmentary distribution. It was exactly this isolation of the single populations that has contributed to the developement of the many forms in which the species is found today.". As a matter of fact, individual specimens from these populations are often easily recogniseable in collection.