The snakeflies of the Mediterranean islands: review and biogeographical analysis (Neuropterida, Raphidioptera)

Abstract

The Mediterranean region representsone of the hotspots of biodiversity of many organisms and among these also of Raphidioptera. With about 250 known species world-wide Raphidioptera is the smallest order of extant holometabolous insects. The Mediterranean region harbors 113 species (= >45% of the world fauna), and of these 33 (= >13% of the world fauna) have been found on islands of the Mediterranean Sea. In the course of the past 50 years most of the larger islands have been intensively explored for Raphidioptera, particularly all islands (except the Baleares) which had no connection to the mainland throughout the whole Pleistocene. Altogether, 11 species of Raphidioptera (9 Raphidiidae, 2 Inocelliidae) are endemic to (usually)one, rarely to a few Mediterranean islands: Phaeostigma (Ph.) euboica (Euboea), Ph. (Aegeoraphidia) prophetica (Rhodes), Ph. (Ae.) karpathana (Karpathos), Ph. (Ae.) biroi (Crete), Ph. (Superboraphidia) minois (Crete), Subilla principiae (Sardinia), S. colossea (Rhodes), Raphidia (R.) peterressli (Chios), R. (R.) ariadne (Crete), Fibla (F.) maclachlani (Corsica, Sardinia, Sicily), F. (Reisserella) pasiphae (Crete). In the Aegean Sea there is a remarkable difference between the eastern and the western islands marked by the so-called Rechinger line based on results of the analysis of the flora. The Raphidioptera confirm this line impressively. It is rather unlikely that further Raphidioptera species endemic to Mediterranean islands are still to be detected – with one exception: the Baleares. A few additional species known from various parts of the continents surrounding the Mediterranean Sea will probably be found on islands so that a total number may be around 40, possibly around 45 species. The possible ways and times of colonization of the islands by Raphidioptera are discussed. The present paper may serve as a basis for studies on natural and particularly on anthropogenic dispersals of snakeflies from island to island, from mainland to islands, and from islands to the mainland in connection with phylogeographic investigations.