Muricidae (Mollusca: Gastropoda) of the Angostura Formation Northwestern Ecuador

Abstract

The muricid fauna of the Late Miocene Angostura Formation, northwestern Ecuador, includes two species previously known from the Gatun Formation of Panama, the Esmeraldas Beds of Ecuador, and other localities in the Caribbean Tertiary. There are also two new species described herein. One, Eupleura olssoni, is most closely related to an unnamed Gatun species; the second, Ceratostoma (Microrhytis) ecuadorium, is most closely related to C. (M.) pecki (Emerson), described from the Atlantic side of the Isthmus of Tehuantepec, Mexico. Thus, the muricid fauna has a closer affinity with the Tertiary beds of the western Atlantic than with the Recent fauna of the eastern Pacific.