Resumen
RESUMEN:This note emphasizes the finding of Myophorella (Myophorella) hillebrandti Reyes and Perez, 1985 (Bivalvia: Trigoniidae), in a previously known fossiliferous assemblage included in one of the lowest levels of the Quebrada Monardes Formation, a Lower Cretaceous nearshore marine to continental sequence, that crops out in the Andean Cordillera, east of Copiapo city (27°16?S Lat). This fact allows extending the geographic distribution of this species in northern Chile, proving to be an important fossil for the establishment of faunistic and chronoestratigraphical comparisons with other contemporaneous fossiliferous localities that have been recently discovered in this area. Its suggested Neocomian age permits to postulate its arrival into the Meridional Andean Basin subsequently to similar species that were developed in the Upper Jurassic of Mexico and Peru. As a consequence, a southern migration of this singular group of Trigoniidae through South American Pacific coastal regions is proposed. Keywords: Stratigraphy, Bivalvia, Trigoniidae, Neocomian, Chile.