New species and records of Triphoroidea (Gastropoda) from Chile

The present study aims to describe specimens of Triphoroidea recently sampled from Chilean waters, with two species from the northern continental shelf and one from the Juan Fernandez Archipelago. Cerithiopsis eiseni Strong and Bertlein, 1939, originally described from western Panama, has its protoconch, operculum and radula illustrated for the first time. Monophorus monocelha new species is recognized by having a very thick shell; yellowish protoconch and brown teleoconch; median spiral cord emerging between the sixth/seventh whorl of teleoconch; a brown mark between the eyes; and radular formula 4-1-1-1-4. Inella basalis (Odhner, 1922) new combination is recorded almost a century after its original description, including data on intraspecific variation in adult size, shape of protoconch, number of axial ribs on teleoconch, and number of basal and supranumerical cords. Cerithiopsis eiseni and Monophorus inonocelha new species share very thick shells and narrow apertures, suggesting a convergent defensive mechanism against predation.