BASTERIA, 68: 93-124 The Orculella of the South species Aegean island arc, a neglected radiation (Gastropoda, Pulmonata, Orculidae) E. Gittenberger National Museum ofNatural History Naturalis, P.O. Box 9517, NL 2300 RA Leiden, The Netherlands;
[email protected] & B. Hausdorf Zoologisches Museum der Universitat Hamburg, Martin-Luther-King-Platz 3, D 20146 Hamburg, Germany;
[email protected] INTRODUCTION The Orcula and Orculella be genera Held, 1837, Steenberg, 1925, canclearly diagnosed addition anatomically (Hausdorf, 1996). In there are slight conchological differences. In Orcula, the of the shell is more less whereas apex or depressed conical, it is more domed in Orculella. More useful as a character is difference in diagnostic a sculpture of the pro- toconch whorls. In Orculella these whorls have prominent spiral striae, whereas in Orcula they are devoid of any distinct sculpture. Orculella cannot be separated conchologically from Sphyradium Charpentier, 1837, and Schileykula Gittenberger, 1983, however. is The genus Orculella particularly speciose in the Cyrenaica in N. Libya (Brandt, 1956) and Asia Minor (Hausdorf, 1996). More isolated species are known from elsewhere in the and N. Mediterraneanarea, e.g. Sicily (Hausdorf, 1988) Morocco (Gittenberger, 1983: 334). Exceptionally widespread is or was O. bulgarica (Hesse, 1915), which is not known from Greece, but has been reported, partly from Holocene deposits only, from Spain, Bulgaria, Turkey, Caucasian Russia, Armenia and Azerbaijan (Bank, 1986; Gittenberger, 1983: 329; Hausdorf, 1996: Such 15). a disjunct pattern is exceptional in western Palaearctic gastropod species. In southern mainland Greece, the and Greek islands, Peloponnese many O. critica 1856) occurs. Orculella (Pfeiffer, is very rare in the northern part of Greece; from that region some records of O.