A revision of the genus Ancilla Lamarck, 1799 (Mollusca : Olividae : Ancillinae)

Abstract

The genus Ancilla Lamarck, 1799, contains 34 valid species and subspecies; 41 names previously applied to the group are reduced to 23, and 11 new species described (Kilburn, 1977, 1980, 1981). A provisional subgeneric classification is proposed. Subgenus Hesperancilla Kilburn, 1981, is established for the Brazilian A. matthewsi Burch & Burch, 1967, and Javancilla Kilburn, 1981, for the Eocene A. boettgeri Martin, 1914. Inadequate data on its type species prevents definition of subgenus. Ancilla s.s. at this stage, but Recent Indo-Pacific taxa are provisionally divided into (a) subgenus Sparellina P. Fischer, 1883, with an autapomorphic pectinate rachidian and (b) subgenera sparella Gray, 1857, and Chilotygma H. &. A. , Adams, 1853, with synplesiomorphic tricuspidate rachidians. The phylogeny and biogeography of the genus are discussed. The subfamily Ancillinae is reclassified, and a tentative cladogram proposed.