|Publication Type:||Journal Article|
|Year of Publication:||1994|
|Authors:||Aspöck, U., Aspöck, H.|
|Journal:||Zeitschrift der Arbeitsgemeinschaft Österreichischer EntomologenZeitschrift der Arbeitsgemeinschaft Österreichischer Entomologen|
Out of the numerous peculiar and in this respect paradoxical distributional patterns of Neuropteroidea four examples at different taxonomical levels - one order, one family, one genus, and two species - are selected. Hypotheses on the origins and formations of these patterns are discussed. 1. The order Raphidioptera (with about 200 extant species) is confined to arboreal zones of the Holarctic. It is, however, intriguing that the order does not occur in the southern hemisphere and in the northern and eastern parts of North America. Formerly accepted theories assuming an immigration of snake-flies from Asia via the Bering Strait to America are rejected. Some striking similarities between American, African, and Iberian Raphidioptera are now interpreted as an indication of relationship, which dates back to the period before the separation of the continents. Possibly the extant Raphidioptera represent - as living fossils - only that small part of the Mesozoic fauna which had become adapted to a temperate climate, whereas the rich subtropical and tropical Mesozoic Raphidiopteran fauna must have died out 2. The Neurorthidae Nakahara (Neuroptera) comprises only 12 known, surprisingly similar species which are assigned to three extremely vicariant genera, Neurorthus COSTA (Balkan Peninsula, Apennines Peninsula, Tyrrhenis and Northern Africa), Nipponeurorthus Nakahara (Japan, Taiwan), and Austroneurorthus Nakahara (southeastern pails of Australia). This distributional pattern is traced back to a formerly huge Pangean distribution which has been split and reduced in the course of the continental drift. The archaic, aquatic larvae enabled these insects to survive along the fringes of the continents. The Neurorthidae are the living fossils of the Neuroptera. 3. The genus Fibla Navas (Raphidioptera: Inocelliidae) comprises two subgenera, Fibla s. str. with two species occurring in western Mediterranean regions (Iberian Peninsula; Northwestern Africa; Corsica, Sardinia, Sicily) and the monotypic Reisserella H. Aspock & U. Aspock endemic to Crete. Why does Fibla not occur on the Apennines Peninsula, on the Balkan Peninsula, in Anatolia and on all other islands of the eastern Mediterranean? Ouroccurrence of other inocelliid species. The assumption of an immigration of a Fibla into Crete from the north would need several additional hypotheses and is therefore unlikely. An immigration from Africa seems therefore much more probable. This event could, however, not have been earlier than during the salinity crisis in the late Miocene, if there was really no earlier connection with Africa in the Tertiary. With respect to the archaic character of the Raphidioptera it cannot entirely be ruled out that the recent distribution reflects the remnants of the old Mesozoic fauna. 4. Libelloides hispanicus (Rambur) (Neuroptera: Ascalaphidae) is confined to the northern Iberian Peninsula and the French parts of the Pyrenees; Libelloid esustulatus (Eversmann) occurs in the Caucasus, in northeastern parts of Anatolia and northwestern parts of Iran. Conspecificity of the two taxa has been repeatedly discussed. Whether they represent two extremely vicariant subspecies or two genetically already isolated sister species is, however, not the crucial question: There is no convincing approach to an explanation of this peculiar distribution from any hypothesized historical stem species. Parallel evolution is, therefore, offered as a provocative alternative of at least heuristic value.