Northern Apennines as centre of speciation: a new Verdanus species group (Hemiptera, Cicadomorpha, Cicadellidae) from Italy and its phylogenetic relationships with V. bensoni and the V. limbatellus group.

Abstract

A small sector of Northern Apennines - the Tuscan-Emilian Apennines - constitutes an interesting diversity centre of a new Verdanus species group closely related to V. bensoni and the V. limbatellus group. It consists of three species: V. tyrannus sp. nov., V. saurosus sp. nov. and V. rosaurus sp. nov., the latter with two subspecies, V. rosaurus rosaurus ssp. nov. and V. rosaurus rex ssp. nov., which doubtless form a monophyletic group (V. rosaurus group). Data on their distribution, ecology and life cycle are added to their original descriptions. The new taxa live allopatrically in a very restricted area and populate in this way a distribution gap of another species group of Verdanus, the V. abdominalis group, present in Italy in the mountain regions of the Alps and Central and Southern Apennines. We present a hypothesis of the origin of the new taxa based on the ecological conditions in the Tuscan-Emilian Apennines during the last Postglacial period and on the limited dispersal ability of these normally brachypterous insects. In addition we discuss possible synapomorphic characters and phylogenetic relationships of the new taxa with each other and with V. bensoni (China) and the V. limbatellus group (V. limbatellus (Zetterstedt), V. kyrilli (Emeljanov), V. sichotanus (Anufriev), V. kaszabi (Dlabola)) and conduct a cladistic analysis. Comparing V. bensoni and the V. limbatellus group on the one hand and the V. rosaurus group on the other, we observe some morphological characters changing often in parallel on the same paths, independently from the phylogenetic hypothesis we proceed from. It is astonishing that within the same morphological characters the range of variation is similar in the species of the comparatively minute area of the Tuscan-Emilian Apennines and the other taxa of the vast areas of northern and central Eurasia.