Notulae orthopterologicae XXI - Le Dolichopoda della Francia e della Spagna

Abstract

The revision of French-Iberian Dolichopoda has led to the identification of four different species of Dolichopoda s. str. One of these (D. azami) seems to have a large geonomy in the French Alps and it had already been noticed in Italy, too. A second species (D. chopardi m.), still new to science, seems to be restricted to the Maritime Alps; the third and the fourth (D. linderi and D. bolivari), already well known, seem to be localized in the Pyrenees and the Cevennes. Owing to their morphological characters Dolichopoda azami and chopardi constitute a very homogeneous group, comprising also D. ligustica, and which could be defined alpine; on the contrary, D. linderi and bolivari are very different from said group and are very similar between them. Such similarity partly emerged from the citological observations of Saltet (1959-1960). We could then set an Alpine group against a Pyrenean one. It is then possible to state that the geographic isolation has a basic importance for the specific differentiation of the French-Pyrenean Dolichopoda, which appears to have descended from a unique, very old, common stock. The elaboration of the analytical key closing the work, shows proof of such affinity and reveals a more complex situation in Italy and Greece where two successive, different immigrations may have taken place. Such theory is fully confirmed by the presence of two subgenera in both peninsulas, that is Dolichopoda and Chopardina (the second having preceded the first: Baccetti 1960). On the whole four Chopardina are known (one in Macedonia, one in Tuscany, two in Corsica) and nineteen Dolichopoda, one of which is caucasian, one anatolian, four distributed among Attica, Peloponnesus and minor islands of Greece, one in Macedonia, three are localized in the coast between Dalmatia and Epirus, three in the Apennines, one practically restricted to the Tuscan Archipelago, three in the Alps and two in the Pyrenees. We could state that the elements of each group have close affinity and that the phenomena of morphological parallelism at great distance are but apparent exceptions: for instance Dolichopoda baccettii and Dolichopoda graeca. As — when there are no conditions of insularity causing a particularly remarkable differentiation specific to many entities — the geographic barriers among the elements of each group are often very scanty, we can consider possible that after the two great immigrations from the East, by which two suhgenera, one after the other, were imported during the Tertiary period (Baccetti, 1960), the phenomena of speciation were largely favoured, in the Quaternary, by the acquisition of troglophilia which has greatly hindered any possible migration.