Studies on Priotrochus obscurus and the systematic position of Priotrochus (Mollusca: Gastropoda: Trochidae)

The systematic status of Priotrochus Fischer, 1879 and the taxonomy of its type species, Trochus obscurus Wood, 1828, are discussed. Although previously regarded as a subgenus of Monilea, observations on the radula and external anatomy reveal little similarity with Monilea and the Umboniinae as a whole. Greater similarity exists with members of the Monodontinae and a position, at generic level, in that subfamily is suggested. The extinct Trochus ponsonbyi Sowerby, 1888, is maintained as a subspecies of Priotrochus obscurus.