ABSTRACT: Here we describe Reticulofenestra cisnerosii nov. sp. a rounded species of “Reticulofenestrid†with a well defined stratigraphic distribution in the Mediterranean Neogene. The first occurrence of this new taxa is placed in the middle part of subchron Thvera (C3n4n); in the subzone CN10b (Okada and Bukry 1980); and the last occurrence is observed into the subchron C3n1r, middle part of subzoneCN11a (Okada andBukry 1980), just before the regular record of Discoaster asymmetricus. In the region studied, this species is linked with warm, moderately saline and relatively fertile waters. This species has also been observed in the equatorial Pacific.