Naticidae (Mollusca:Mesogastropoda) From the Neogene of Northwestern Ecuador

Abstract

The Bolivar Trough from Colombia to Ecuador was the longest lasting Neogene seaway allowing for the free movement of molluscan species between the Caribbean and Pacific faunal provinces. This paper is intended to show the relationship of the Ecuadorian Neogene naticid fauna to the fossil and Recent Caribbean and eastern Pacific faunas. The naticid fauna from the Neogene formations of northwestern Ecuador consists of 17 species, including eight known from the Recent fauna of the Tropical East Pacific, four previously known only from the Caribbean Tertiary, one Caribbean Tertiary and Recent species, previously reported from Ecuador, three previously known only from the Ecuadorian Neogene, and one from the Tertiary of the northern Pacific. Although it was anticipated that a majority of the species from the Ecuadorian Neogene would have their origin in the Caribbean fauna, only five of the seventeen species can be considered Caribbean species; with only one of those occurring in the Recent Caribbean fauna; however, several others have analogues in the Caribbean and may have originated there, and two have California-Japanese relationships.