Songs, genetics, and morphology: revealing the taxonomic units in the European Cicadetta cerdaniensis cicada group, with a description of new taxa (Hemiptera: Cicadidae) THOMAS HERTACH 1 *, TOMI TRILAR 2 , ELIZABETH J. WADE 3 , CHRIS SIMON 3,4 and PETER NAGEL 1 1 Department of Environmental Sciences, Biogeography, University of Basel, St. Johanns-Vorstadt 10, CH – 4056 Basel, Switzerland 2 Slovenian Museum of Natural History, Prešernova 20, SI – 1000 Ljubljana, Slovenia 3 Department of Ecology and Evolutionary Biology, University of Connecticut, 75 North Eagleville Road, Storrs, CT 06269, USA 4 School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand Received 27 June 2014; revised 2 September 2014; accepted for publication 7 September 2014 Recent acoustic studies have revealed that Cicadetta montana (Scopoli, 1772), which was once thought to be a single widespread Palaearctic cicada species, is actually a complex of many taxa. Although some song patterns are very distinct, others comprise groups of closely related species, as in the case of Cicadetta cerdaniensis Pu- issant & Boulard, 2000, Cicadetta cantilatrix Sueur & Puissant, 2007, and Cicadetta anapaistica Hertach, 2011. Seven spatially or behaviourally isolated metapopulations belonging to this song group from Italy and Switzer- land were detected and investigated using acoustic, molecular, and morphological methods. Taxonomic decisions in this group are challenging because of a lack of truly diagnostic morphological characters, variously coloured morphs, qualitatively intermediate song patterns in contact zones, and strong temperature dependence of song- duration characters. Molecular genetic studies suggest rapid speciation resulting in incomplete lineage sorting and introgression. It is only by using multiple sources of data that species can be delimited. The new species Cicadetta sibillae sp. nov. and the new subspecies Cicadetta anapaistica lucana ssp. nov. were described using the mi- crostructure of the male calling songs. Cicadetta sibillae sp. nov. occurs from southern Switzerland to central Italy, and is the most abundant cicada in the Northern Apennine. Cicadetta anapaistica lucana ssp. nov. is endemic to a small southern Italian distribution range, and seems to be threatened by habitat loss and fragmen- tation. There is strong evidence that current distribution patterns and phylogenetic relationships of the Cicadetta cerdaniensis group are linked to speciation events in Pleistocene glacial refugia in the Italian, Iberian, and Balkan peninsulas. © 2015 The Linnean Society of London, Zoological Journal of the Linnean Society, 2015, 173, 320–351. doi: 10.1111/zoj.12212 ADDITIONAL KEYWORDS: allopatric speciation – bioacoustics – dimorphism – glacial refugia – hybridi- zation – Italy – song variability – Switzerland – temperature dependency – timbal movements. INTRODUCTION Cicadas are well known for their songs, which males produce by the movement of paired timbals. These songs act as species-specific pre-mating barriers, and have been used extensively to reveal hidden taxonomic di- versity (e.g. Dugdale & Fleming, 1978; Gogala & Trilar, 2004; Quartau & Simões, 2006; Puissant & Sueur, 2010; Marshall et al., 2011). Songs appear to evolve more rapidly than morphological characters and provide a *Corresponding author. E-mail: thomas.hertach@unibas.ch Zoological Journal of the Linnean Society, 2015, 173, 320–351. With 12 figures © 2015 The Linnean Society of London, Zoological Journal of the Linnean Society, 2015, 173, 320–351 320 Downloaded from https://academic.oup.com/zoolinnean/article-abstract/173/2/320/2449784 by guest on 17 June 2020