Journal of Conchology 44/4

l and snails of the s outheast – C entral a egean i slets 319

Table 1 Characteristics of the studied islets.

Area (km2)

Altitude (m)

Distance from the nearest larger island (km)

Islets

Vegetation

Substrate

Dyo Adelfoi East Dyo Adelfoi West

0.22 0.13 7.93 0.01 0.43 0.14 0.52 1.27 0.03 0.02 0.01 0.43 0.23 0.28 0.98 0.14 0.02 0.02 0.1

164 7.5 from Syrna

phrygana phrygana

limestone limestone limestone, sediments limestone limestone limestone limestone, sediments limestone limestone limestone limestone limestone limestone, sediments limestone limestone limestone, sediments limestone limestone limestone

100 1.3 from Dyo Adelfoi East

Syrna

322 29 from Astypalaia

phrygan, maquis, cultivations

Katsika

40 25 from Mesi 70 0.3 from Plakida 50 0.9 from Mesi 80 0.6 from Syrna

phrygana phrygana phrygana

Mesi

Stefania Plakida

phrygan, maquis

Zafora Megali

227 34.4 from Syrna

phrygana phrygana phrygana phrygana

Sochas

80 0.7 from Zafora Megali 60 1.7 from Zafora Megali 90 7.2 from Zafora Megali 40 0.4 from Karavia North 60 25.8 from Zafora Megali 100 0.2 from Ounio East 150 25.8 from Zafora Megali 200 30.5 from Karpathos

Zafora Mikri Karavia North Karavia South

herbs

Chamili

phrygana

Ounio West Ounio East

phrygana phrygana phrygana

Astakida

Astakidopoula

80 0.1 from Astakida 50 2 from Astakida

phrygana, herbs

Sial

phrygana

Avgo

80 17.8 from Zafora Megali

–

and Sial were studied over a period of 4 days (20–23/4/1989). The second expedition was supported by the Leventis Foundation, as part of a project studying the geology, biodiversity and ecology of 50 islets in the Aegean and the Ionian archipelagoes. In this case, the Syrna cluster (Syrna, Dyo Adelfoi East, Plakida, Mesi and Stefania) was studied over the course of 4 days (26–29/10/1993). The third expedition was organized by the North Karpathos-Saria Management Body, under the terms of a project investigating biodiversity in Natura 2000 areas. The collection (15/12/2017) took place on Astakida and Astakidopoula. Finally, the fourth was a joint expedition by the University of Michigan and the Natural History Museum of Crete. Material from the islets of Ounio East, Ounio West, Chamili, Karavia North, Sochas, Zafora Megali, Zafora Mikri, Dyo Adelfoi East and Plakida was collected over three days (16–18/5/2018). No material was available from Dyo Adelfoi West and Katsika islets. All of the flora and fauna on Avgo have been destroyed, as the islet was used for military exercises for many decades.

The present work is the result of an extensive study of the malacological material collected dur ing four scientific expeditions between 1989 and 2018, now held in the Natural History Museum of Crete. The rich shell collections and preserved alcohol material have enabled us to enrich our knowledge of the terrestrial malacofauna on these islets and clarify certain taxonomic uncer tainties. We also discuss the biogeographic rela tions between the islets and the neighbouring islands in the Aegean. M aterIal and Methods The material we studied is the outcome of four scientific expeditions, now stored in the malaco logical collections of the Natural HistoryMuseum of Crete – University of Crete. The authors par ticipated in the first three expeditions. The first was a joint project involving scientists from the universities of Athens and Crete, sup ported by the Hellenic Navy. In particular, the islets of Ounio East, Ounio West, Chamili, Zafora Megali and Zafora Mikri, Sochas, Karavia North, Karavia South, Avgo, Astakida, Astakidopoula