75 (3): 497– 521 20.12.2017 © Senckenberg Gesellschaft für Naturforschung, 2017. High cryptic diversity in aquatic insects: an integrative approach to study the enigmatic Leuctra inermis species group (Plecoptera) Simon Vitecek *, 1, 4, #, Gilles Vinçon 2, #, Wolfram Graf 3 & Steffen U. Pauls 4 1 Department for Limnology and Bio-Oceanography, Universität Wien, UZA I, Althanstrasse 14, 1090 Vienna, Austria; Simon Vitecek [simon.
[email protected]] — 2 55 Bd Joseph Vallier, F 38100 Grenoble, France; Gilles Vinçon [
[email protected]] — 3 Institute of Hydrobio- logy and Aquatic Ecology Management, University of Natural Resources and Life Sciences, Gregor-Mendel-Straße 33, 1180 Vienna, Austria; Wolfram Graf [
[email protected]] — 4 Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, 60325 Frankfurt am Main, Germany; Steffen U. Pauls [
[email protected]] — * Corresponding author; # Equally contributing authors Accepted 05.x.2017. Published online at www.senckenberg.de/arthropod-systematics on 11.xii.2017. Editors in charge: Gavin Svenson & Klaus-Dieter Klass Abstract Within the genus Leuctra (Plecoptera: Leuctridae) the L. inermis species group comprises 17 – 18 species in which males lack the char- acteristic tergal abdominal ornamentation of many Leuctra species, and females have an accessory receptacle in the dorsal portion of the vagina. Taxonomically the group is challenging, and congruence of existing morphological species concepts and phylogenetic relationships of taxa is hitherto not assessed. Here, we estimate phylogenetic relations of morphologically defined species by concatenated maximum likelihood (ML) and Bayesian combined species tree and species delimitation analysis. We aim to clarify the status of 15 European species of the L.