As part of our detailed study of the Caucasian mayfly fauna, we describe Epeorus (Caucasiron) abditussp. nov., a new species of the genus EpeorusEaton, 1881,subgenusCaucasiron Kluge, 1997, based on larvae collected in Türkiye, Georgia, and Russia. We use several methodological approaches to delimit the new species by analysing COI sequence data and larval morphology. We provide a comparison with related taxa and diagnostic characters allowing determination of the larvae. We also update the identification key for the Caucasian species of E. (Caucasiron) with E. (C.) abditussp. nov. and two recently described species, E. (C.) hyrcanicus Hrivniak & Sroka, 2021 and E. (C.) tripertitus Hrivniak & Sroka, 2022.

• Klíčová slova
• Aquatic insects, species delimitation, taxonomy,
• Publikační typ
• časopisecké články MeSH

A new species, Serratella leonidi Martynov & Palatov, sp. nov., is described from Tajikistan based on immature stage. Based on larval material from Iran including the topotypes, Serratella elissa Jacobus, Zhou & McCafferty, 2009 is complementary described, and its generic placement is clarified. The delimitation of three genera that are members of the tribe Hyrtanellini Allen, 1980, namely Serratella Edmunds, 1959, Torleya Lestage, 1917 and Quatica Jacobus & McCafferty, 2008 is briefly discussed. The phylogenetic reconstruction of Hyrtanellini based on the COI gene showed the relations of representatives of these genera on the one hand, and distinct delimitation of Serratella leonidi sp. nov. and S. elissa on the other. A list of species from Western and Central Asia attributed to Hyrtanellini, their currently known distribution and a key for the determination of the larvae are proposed.

• Klíčová slova
• COI, Iran, Tajikistan, distribution, key, larva, spiny crawler mayflies, type locality, variation,
• Publikační typ
• časopisecké články MeSH

The mayfly genus Alainites Waltz & McCafferty, 1994 encompassed 20 species and was represented across the West Palaearctic region by six species. Based on morphological (nymphal characters) and molecular (mitochondrial COI sequences) evidence, two new species are described: A.bengunn sp. nov. from Sardinia and A.gasithi sp. nov. from Israel. Both species are confined to narrow distribution ranges, in line with most of their congeners from the region. The key nymphal traits are discussed and identified to distinguish species in the group.

• Klíčová slova
• COI, Israel, Italy, Sardinia, West Palaearctic, mayfly, microendemics, systematics,
• Publikační typ
• časopisecké články MeSH

Based on the original type material, the nymphal stage of the mayfly Takobiamaxillare is redescribed; in parallel, a lectotype is designated. Takobiamaxillare is the type species of the genus Takobia, and an accurate and complete knowledge of its morphology is crucial to the delimitation of this problematic genus and clarification of its phylogenetic affinities. Ambiguous characters, previously reported for this species in the literature are clarified. Furthermore, two new species in the same genus are described, namely Takobiasinusopalpata sp. nov. and Takobiashughnonica sp. nov. based on the morphology of nymphs from Central Asia, supplemented with COI sequences. Implications for the systematics of Takobia and related taxa are discussed and the need for an extensive phylogenetic study of this group is stressed.

• Klíčová slova
• Alainites, Nigrobaetis, mayflies, new species, redescription, systematics, taxonomy,
• Publikační typ
• časopisecké články MeSH

A new species, Epeorus (Caucasiron) hyrcanicussp. nov., is described based on larval morphology and molecular data (COI) containing sequences from all Caucasian Caucasiron species described to date. The species is distributed in the Hyrcanian forest of southeastern Azerbaijan and northwestern Iran. Based on our wide-range sampling, the new species is likely endemic to this area. The most pronounced larval morphological diagnostic characters are the coloration pattern of abdominal sterna (a pair of oblique stripes and stripe-like medio-lateral maculae) and terga (triangular medial maculae), poorly developed projection of the costal margin of gill plates III, presence of hair-like setae on the surface of abdominal terga, and relatively wide shape of gill plates VII (in natural position from ventral view). The diagnostic characters are compared to related species, and primary information to habitat is provided.

• Klíčová slova
• Caucasus, mayflies, molecular species delimitation, taxonomy,
• Publikační typ
• časopisecké články MeSH

Based on a recent field survey in Iraqi Kurdistan and a critical evaluation of previously published data, 37 mayfly species are listed as occurring in Iraq. We collected and identified nine species as new for the country and corrected some previously published records. For several species scarcely treated in the literature, we provide information allowing their identification in the larval stage to promote the acquisition of reliable faunistic data from Iraq in the future.

• Klíčová slova
• Ephemeroptera, Iraq, Middle East, aquatic biodiversity, mayflies,
• Publikační typ
• časopisecké články MeSH

The Caucasus and adjacent areas are inhabited by fifteen species of mayflies of the genus Epeorus, subgenus Caucasiron Kluge, 1997 (Heptageniidae). This identification guide aims to facilitate an accurate species identification of their larvae and sum up all available information on their taxonomy and distribution. An identification key is provided, and the important diagnostic characters of all species are described and illustrated. The larva of E. (C.) insularis (Braasch, 1983) is described for the first time. This study enables the routine identification of Caucasiron larvae necessary for biomonitoring and hydrobiological research in the Caucasus region.

• Klíčová slova
• aquatic insects, identification key, mayflies, morphology,
• Publikační typ
• časopisecké články MeSH

Combining morphological and molecular data in an integrative approach, three new mayfly species of Epeorus (Caucasiron) are described. These include Epeorus (Caucasiron) alborzicus Hrivniak & Sroka, sp. nov. and Epeorus (Caucasiron) shargi Hrivniak & Sroka, sp. nov. from northern Iran, and Epeorus (Caucasiron) zagrosicus Hrivniak & Sroka, sp. nov. from central Iran. They are unambiguously delimited using both distance-based and likelihood-based approaches in the analyses of barcode COI sequences. Each new species is compared with other species of the subgenus and morphological diagnostic characters are provided. Based on extensive sampling of streams throughout the country, the distribution and habitat preferences of all Caucasiron species in Iran are assessed. Altogether, there are now six species recorded, among them also E. (C.) nigripilosus Sinitshenkova, 1976 is reported for the first time in Iran. Five species are distributed in the Alborz Mts. in northern Iran, one species was found in the Zagros Mts. in central Iran.

• Klíčová slova
• Caucasus, Middle East, barcoding, diversity, mayflies, taxonomy,
• Publikační typ
• časopisecké články MeSH

Two new species of the mayfly family Oligoneuriidae are described based on larval specimens recently collected in Iran. The first new species, Oligoneuriella tuberculata Godunko & Staniczek, sp. nov., can be distinguished from all its congeners by the presence of pronounced protuberances posteromedially on abdominal terga, highly reduced paracercus, large lamella of gill I, and setation on hind margin of middle and hind femora confined to their basal halves. The second species, Oligoneuriopsis villosus Bojková, Godunko, & Staniczek, sp. nov., remarkably belongs to a mostly Afrotropical genus. The new species clearly differs from all its congeners in the shape of setae on the surface of gills and terga, pattern of body colouration, and the shape of posterolateral projections of abdominal segments. Except for the species description, the generic diagnosis of Oligoneuriopsis Crass, 1947 is briefly discussed. COI barcode sequences of both new species are provided and molecular species delimitation is tested using distance-based and likelihood-based approaches, with both new species unambiguously recognised as separate lineages. The analysis of COI also corroborates the respective affinities of both new species, estimated based on morphology. The two new species of Oligoneuriidae described herein highlight the importance of the Middle East as a centre of diversity of this mayfly family within the Palaearctic.

• Klíčová slova
• Oligoneuriella, Oligoneuriopsis, Barcoding, Middle East, mayflies, new species, taxonomy,
• Publikační typ
• časopisecké články MeSH