title: Complex within a Complex: Integrative Taxonomy Reveals Hidden Diversity in Cicadetta brevipennis (Hemiptera: Cicadidae) and Unexpected Relationships with a Song Divergent Relative.
abstract: Multiple sources of data in combination are essential for species delimitation and classification of difficult taxonomic groups. Here we investigate a cicada taxon with unusual cryptic diversity and we attempt to resolve seemingly contradictory data sets. Cicada songs act as species-specific premating barriers and have been used extensively to reveal hidden taxonomic diversity in morphologically similar species. The Palaearctic Cicadetta montana species complex is an excellent example where distinct song patterns have disclosed multiple recently described species. Indeed, two taxa turned out to be especially diverse in that they form a "complex within the complex": the Cicadetta cerdaniensis song group (four species studied previously) and Cicadetta brevipennis (examined in details here). Based on acoustic, morphological, molecular, ecological and spatial data sampled throughout their broad European distribution, we find that Cicadetta brevipennis s. l. comprises five lineages. The most distinct lineage is identified as Cicadetta petryi Schumacher, 1924, which we re-assign to the species level. Cicadetta brevipennis litoralis Puissant & Hertach ssp. n. and Cicadetta brevipennis hippolaidica Hertach ssp. n. are new to science. The latter hybridizes with Cicadetta brevipennis brevipennis Fieber, 1876 at a zone inferred from intermediate song patterns. The fifth lineage requires additional investigation. The C. cerdaniensis and the C. brevipennis song groups exhibit characteristic, clearly distinct basic song patterns that act as reproductive barriers. However, they remain completely intermixed in the Bayesian and maximum likelihood COI and COII mitochondrial DNA phylogenies. The closest relative of each of the four cerdaniensis group species is a brevipennis group taxon. In our favoured scenario the phylogenetic pairs originated in common Pleistocene glacial refuges where the taxa speciated and experienced sporadic inter-group hybridization leading to extensive introgression and mitochondrial capture.
authors.affiliation: Department of Environmental Sciences, Biogeography, University of Basel, Basel, Switzerland.|Naturhistorisches Museum der Burgergemeinde Bern, Department of Invertebrates, Bern, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hertach
authors.affiliation: Muséum-Jardin des Sciences, Mairie de Dijon, Dijon, France.|Institut de Systématique, Évolution, Biodiversité, Muséum national d'Histoire naturelle, Sorbonne Universités, Paris, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Puissant
authors.affiliation: Slovenian Academy of Sciences and Arts, Ljubljana, Slovenia.
authors.forename: Matija
authors.initials: M
authors.lastname: Gogala
authors.affiliation: Slovenian Museum of Natural History, Ljubljana, Slovenia.
authors.forename: Tomi
authors.initials: T
authors.lastname: Trilar
authors.affiliation: Department of Environmental Sciences, Biogeography, University of Basel, Basel, Switzerland.|Naturhistorisches Museum der Burgergemeinde Bern, Department of Invertebrates, Bern, Switzerland.
authors.forename: Reto
authors.initials: R
authors.lastname: Hagmann
authors.affiliation: Naturhistorisches Museum der Burgergemeinde Bern, Department of Invertebrates, Bern, Switzerland.|University of Bern, Institute of Ecology and Evolution, Bern, Switzerland.
authors.forename: Hannes
authors.initials: H
authors.lastname: Baur
authors.affiliation: Department of Zoology, Karl Franzens University of Graz, Graz, Austria.
authors.forename: Gernot
authors.initials: G
authors.lastname: Kunz
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, United States of America.|United States Department of Agriculture, Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida, United States of America.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Wade
authors.affiliation: Department of Environmental Sciences, Biogeography, University of Basel, Basel, Switzerland.|Life Sciences Department, University of Roehampton, London, United Kingdom.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Loader
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut, United States of America.
authors.forename: Chris
authors.initials: C
authors.lastname: Simon
authors.affiliation: Department of Environmental Sciences, Biogeography, University of Basel, Basel, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Nagel
mesh_terms: D000162:Acoustics; D000818:Animals; D044822:Biodiversity; D004272:DNA, Mitochondrial / Q000235:genetics; D003576:Electron Transport Complex IV / Q000235:genetics; D005260:Female; D006430:Hemiptera / Q000033:anatomy & histology / Q000145:classification*; D016014:Linear Models; D008297:Male; D010802:Phylogeny; D010858:Pigmentation; D025341:Principal Component Analysis; D019655:Quantitative Trait, Heritable; D013696:Temperature; D014828:Vocalization, Animal / Q000502:physiology*; D014921:Wings, Animal / Q000033:anatomy & histology
chemical_list: D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV