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We describe a new species of Prosopistoma collected in the High Atlas Mountains of Morocco. Prosopistoma maroccanumsp. nov. appears to be morphologically more similar to the European highly endangered P. pennigerum (Müller, 1785) than to the other Maghrebian species, P. alaini Bojkova & Soldán, 2015. A gene tree including the few available barcode sequences of Palearctic Prosopistoma specimens is provided. Possible affinities with West African species are also discussed.

Ecdyonurus aurasiussp. nov., a micro-endemic species reported from several streams within the Aurès Mountains (north-eastern Algeria), is described and illustrated at nymphal, subimaginal and imaginal stages of both sexes. Critical morphological diagnostic characters distinguishing the new species are presented, together with molecular affinities as well as notes on the biology and distribution of the species.

Based on recently collected larvae from Algeria and Morocco, the species delimitation within the genus Centroptilum Eaton, 1869 in that region is validated. Two new species are described and illustrated, one from north-eastern Algeria, and one from North Morocco, using an integrated approach with morphological and molecular evidence. A table summarising the morphological differences between the new species and Centroptilum luteolum (Müller, 1776) from Central Europe is provided. Further, molecular evidence for additional undescribed species of Centroptilum in other regions of the West Palearctic is provided and discussed.

A new species belonging to the speciose genus Electrogena ZurwerraTomka, 1985 is described based on all stages from material collected in Switzerland, northern Italy and Slovenia. Electrogena brulini Wagner sp. nov. is closely related to E. gridellii (Grandi, 1953). A genetic analysis based on the mitochondrial gene CO1, including 9 specimens from 5 populations, reveals a K2P distance of 22% between both species. Our investigations demonstrate that the description of the nymph of E. gridellii sensu Belfiore (1996) refers in fact to both species. Therefore, E. gridellii is redescribed in all stages. The number of bristles on each mandibular prostheca in the nymphs, the shape of titillators in male genitalia and the shape of the subanal plate in female imagines are the main characters allowing discrimination of these two species. This study also shows that in this case it is possible and helpful to use colour patterns to separate two closely related species. The re-examination of the type material of Electrogena vipavensis ZurwerraTomka, 1986 described from western Slovenia indicates that this species is a junior subjective synonym of E. gridellii.

Background Larvae of the Holarctic mayfly genus Rhithrogena Eaton, 1881 (Ephemeroptera, Heptageniidae) are a diverse and abundant member of stream and river communities and are routinely used as bio-indicators of water quality. Rhithrogena is well diversified in the European Alps, with a number of locally endemic species, and several cryptic species have been recently detected. While several informal species groups are morphologically well defined, a lack of reliable characters for species identification considerably hampers their study. Their relationships, origin, timing of speciation and mechanisms promoting their diversification in the Alps are unknown. Results Here we present a species-level phylogeny of Rhithrogena in Europe using two mitochondrial and three nuclear gene regions. To improve sampling in a genus with many cryptic species, individuals were selected for analysis according to a recent DNA-based taxonomy rather than traditional nomenclature. A coalescent-based species tree and a reconstruction based on a supermatrix approach supported five of the species groups as monophyletic. A molecular clock, mapped on the most resolved phylogeny and calibrated using published mitochondrial evolution rates for insects, suggested an origin of Alpine Rhithrogena in the Oligocene/Miocene boundary. A diversification analysis that included simulation of missing species indicated a constant speciation rate over time, rather than any pronounced periods of rapid speciation. Ancestral state reconstructions provided evidence for downstream diversification in at least two species groups. Conclusions Our species-level analyses of five gene regions provide clearer definitions of species groups within European Rhithrogena. A constant speciation rate over time suggests that the paleoclimatic fluctuations, including the Pleistocene glaciations, did not significantly influence the tempo of diversification of Alpine species. A downstream diversification trend in the hybrida and alpestris species groups supports a previously proposed headwater origin hypothesis for aquatic insects. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0758-1) contains supplementary material, which is available to authorized users.