A SYSTEMATIC REVISION OF THE VITRINID SEMISLUGS OF THE AZORES (GASTROP0DA:PULMONATA) PETER B. MORDAN' AND ANTONIO M.F. MART INS^ '~e~artmentof Zoology, Cromwell Road, London S W7 5BD, UK E-mail:
[email protected]. uk. 2~epartmentof Biology, University of the Azores, Ponta Delgada, S6o Miguel, Azores, Portugal. E-mail:
[email protected] (Received 19 November 2000; accepted 9 February 2001) ABSTRACT A total of six species, all endemic, are recognised in a comprehensive taxonomic revision of the vitrinid semi-slugs of the Azores. All are referred to the genus Plutonia on the basis of the disposition of the penial retractor muscle. One species, P. brevispira, is highly unusual in lacking a vaginal stimulator and having a large, elaborate penis which would appear to function as an intromittant organ during copulation. INTRODUCTION 1987; Morales, Ibaiiez & Alonso, 1988; Valido, Alonso & Ibaiiez, 1990; Valido, Groh, Ibaiiez & Alonso, 1993) The principal island groups of the eastern north- and Madeira (Groh & Hemmen, 1986), there is no Atlantic, the Azores, the Canaries and Madeira, pro- comprehensive modern account of the Vitrinidae of vide an outstanding opportunity to study a rich variety the Azores. The present paper addresses this gap, and of evolutionary radiations in areas relatively close to presents a revision of the vitrinid semi-slugs of the continental Europe. Together with the Cape Verdes Azores based on extensive material collected over the and the Selvagens they form a region called Macaro- last thirty years from throughout the archipelago. nesia, though the biogeographic utility of such a grouping has been questioned (Beyhl, Mies & Ohm, 1995).