Taxonomic notes on the genus Baetiella Uéno, 1931 (Ephemeroptera, Baetidae), with description of three new species from Thailand.

Based on material recently collected in northern Thailand, the present study provides an updated of the genus Baetiella, including Gratia. It comprises six species in Thailand, three of them being new species: Baetiella (Gratia) narumonae, Baetiella (Gratia) sororculaenadinae, Baetiella (Baetiella) bispinosa, Baetiella (Baetiella) baeisp. nov., Baetiella (Baetiella) lannaensissp. nov. and Baetiella (Baetiella) bibranchiasp. nov.Baetiella (Baetiella) baeisp. nov. can be distinguished from other species by the reduction of the posteromedian protuberances on abdominal tergites I-III, the asymmetrical coniform terminal segment of labial palp, the distal margin of abdominal sternites VII-X each with a row of long, spatulate setae, the dorsal margin of femur with two long, robust setae distally. Baetiella (Baetiella) lannaensissp. nov. is diagnosed by the posteromedian protuberances present on tergites I-VIII, dorsal margin of femur with a regular row of long, rounded, ciliated setae and body surface covered with numerous, dense, rounded scale-like setae. Baetiella (Baetiella) bibranchiasp. nov. can be separated from other species by coxal gills present at the base of forelegs and midlegs. The molecular study based on the mitochondrial gene COI and a larval key to species of Thai Baetiella are also provided.

A comprehensive DNA barcoding reference database for Plecoptera of Switzerland.

DNA barcoding is an essential tool in modern biodiversity sciences. Despite considerable work to barcode the tree of life, many groups, including insects, remain partially or totally unreferenced, preventing barcoding from reaching its full potential. Aquatic insects, especially the three orders Ephemeroptera, Plecoptera, and Trichoptera (EPT), are key freshwater quality indicators worldwide. Among them, Plecoptera (stoneflies), which are among the most sensitive aquatic insects to habitat modification, play a central role in river monitoring surveys. Here, we present an update of the Plecoptera reference database for (meta)barcoding in Switzerland, now covering all 118 species known from this country. Fresh specimens, mostly from rare or localized species, were collected, and 151 new CO1 barcodes were generated. These were merged with the 422 previously published sequences, resulting in a dataset of 573 barcoded specimens. Our CO1 dataset was delimited in 115 CO1 clusters based on a priori morphological identifications, of which 17% are newly reported for Switzerland, and 4% are newly reported globally. Among the 115 CO1 clusters, 85% showed complete congruence with morphology. Distance-based analysis indicated local barcoding gaps in 97% of the CO1 clusters. This study significantly improves the Swiss reference database for stoneflies, enhancing future species identification accuracy and biodiversity monitoring. Additionally, this work reveals cryptic diversity and incongruence between morphology and barcodes, both presenting valuable opportunities for future integrative taxonomic studies. Voucher specimens, DNA extractions and reference barcodes are available for future developments, including metabarcoding and environmental DNA surveys.

A new species of the genus Alainites Waltz & McCafferty, 1994 (Ephemeroptera, Baetidae) from the north of Morocco.

A new species of Alainites is described from northern of Morocco Alainitesalbaisp. nov. It can be separated from the other west Palearctic species by the gill number, the spination of the distal margin of tergites, the leg setation, and the paraproct shape and spination. This species is widespread in the study area but never abundant. It prefers small to medium streams with slow flow, and does not seem to be very sensitive to pollution and water logging activities.

A new species of the Baetisfuscatus group (Ephemeroptera, Baetidae) from Morocco.

Baetisrifensissp. nov. is the first representative of the Baetisfuscatus group to be described from the Maghreb. It was collected from streams in the Rif region of northern Morocco. All species of the B.fuscatus group are morphologically very similar, with slight differences in colour. Thus, in addition to morphological description, species delimitation based on genetic evidence was carried out. The new species was compared with other members of the B.fuscatus group from the Palaearctic region.

New species of Nigrobaetis from Southeast Asia (Ephemeroptera, Baetidae).

Based on larvae collected in the Philippines, Borneo (Kalimantan), Sumba, and Sumatra, the presence of the genus Nigrobaetis in the Philippines and Indonesia is reported for the first time. Six new species are described and illustrated, two from the Philippines and four from Indonesia. A larval key to all Nigrobaetis species of the Philippines, Indonesia and neighbouring continental Southeast Asia is provided, morphological differences to the species of Taiwan are discussed as well. The eggs of three new species are described, and the morphology of the eggs of Nigrobaetis is briefly discussed.

First report of the Afrotropical genus Securiops Jacobus, McCafferty & Gattolliat (Ephemeroptera, Baetidae) from Southeast Asia, with description of a new species.

Recent collections in Thailand revealed the occurrence of the genus Securiops in Asia, formerly known from the Afrotropical Realm only. A new species of Securiops is described and illustrated based on larvae and eggs. Eggs of this genus are described for the first time. Morphological differences between the new species and the species from Africa are discussed. The number of species in the genus Securiops is augmented to five.

Baetidae (Baetidae, Ephemeroptera) in the Maghreb: state of the art, key, and perspectives.

Among mayflies, Baetidae are often considered as easy to recognise at the family level, but difficult to identify at lower level. In several faunistic or ecological studies, the identification remains at the family level; Baetidae are generally considered as widespread and ubiquitous, therefore as poorly informative for ecological studies or bioassessments. Here, a straightforward identification key is offered to larvae of the ten genera of Baetidae reported from Maghreb based on easily observable and understandable characters. The diversity, ecology, and distribution of each taxonomic unit (genera or subgenera) are discussed and the main difficulties for deeper identification are pointed out. Future challenges and remaining taxonomic riddles for Maghrebian Baetidae are detailed.

A new, widespread genus of Baetidae from South Asia (Insecta, Ephemeroptera).

Material collected on different islands across South Asia revealed a new genus of Baetidae with a widespread distribution, Arcobaetisgen. nov. The larvae present important similarities with Nigrobaetis, but have paraglossae dorsally with an arc of long, spine-like setae in distal area; long, slightly feathered setae between prostheca and mola of both mandibles; and very slender legs with row of short setae at dorsal margin of femur. The male imago has an extraordinarily small 3rd (apical) segment of gonostylus, which is much narrower than the apex of the 2nd segment. The new genus includes five species: A.sumbawensissp. nov. is described from Sumbawa (Indonesia) based on larvae, A.sumatrensissp. nov. from Sumatra (Indonesia) based on larvae, A.bornensissp. nov. from Borneo (Brunei) based on larvae, and A.sripadaisp. nov. (type species) is described from Sri Lanka based on a reared male imago with its larval and subimaginal exuviae; A.gracilentus (Chang & Yang, 1994), comb. nov. from Taiwan, formerly described in Margobaetis Kang & Yang, 1994, a subgenus of Baetis Leach, 1815, and subsequently transferred to the genus Nigrobaetis Kazlauskas (in Novikova & Kluge), 1987, is transferred to the new genus. A key to the larvae of all species is provided. Morphological similarities and the relationship of the new genus to other genera of Baetidae are discussed.

First report of the genus Tenuibaetis (Ephemeroptera, Baetidae) from Thailand revealing a complex of cryptic species.

A new species of the genus Tenuibaetis Kang & Yang, 1994 is described from Thailand and the genus is reported for the first time from this country. Tenuibaetispanhai sp. nov. is easily distinguished from other known Tenuibaetis by the complete absence of hindwing pads. Molecular evidence based on COI confirmed the validity of the new species. Additional putative species of Tenuibaetis based on molecular evidence only are considered as Molecular Operational Taxonomic Units (MOTUs) without description. The morphological characters of the new species and its closely related species are discussed; a key to the Oriental species is provided.

Megabranchiella gen. nov., a new mayfly genus (Ephemeroptera, Baetidae) from Thailand with description of two new species.

Megabranchiella gen. nov. (Ephemeroptera: Baetidae) is established as a new baetid mayfly genus from northern Thailand. Two new species, Megabranchiellascutulata sp. nov. and Megabranchiellalongusa sp. nov., are described. This genus is distinguished from other Baetidae by abdominal segment I, bearing a pair of enlarged, ventrally oriented single gills, covering abdominal sternites II-V; other gills have normal size and are dorsolaterally oriented. The two new species Megabranchiellalongusa sp. nov. and Megabranchiellascutulata sp. nov. can be differentiated by the setation of femur dorsal margin and the shape of abdominal gill I. This mayfly genus was found in flowing water with cobble microhabitats in headwater streams of northern Thailand.

Two new species of Centroptilum Eaton, 1869 from North Africa (Ephemeroptera, Baetidae).

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 Centroptilumluteolum (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 widespread new genus of Baetidae (Baetidae, Ephemeroptera) from Southeast Asia.

A reinvestigation of type and other material of Baetisjavanicus Ulmer, 1913 and Baetissabahensis Müller-Liebenau, 1984, together with new material from Southeast Asia revealed a new genus, Branchiobaetis gen. nov. The above species are formally assigned to the new genus Branchiobaetis gen. nov. It is characterized by the presence of accessory gills ventrally near fore coxa and at the base of maxillae, a peculiar folding of the gonostyli developing under the cuticle of last instar male larvae, together with a unique combination of other larval characters. Besides the two formerly described species, five new species are identified using a combination of morphology and molecular characters (COI, Kimura 2-parameter distances), four species from Sumatra and one from the Philippines. They are described and illustrated at the larval stage. Additionally, a complementary description of larva and adult stages of the generic type species B.javanicus comb. nov. as well as the first description of the eggs are provided. Furthermore, new reports of B.javanicus comb. nov. and B.sabahensis comb. nov. are indicated. The distribution of Branchiobaetis gen. nov. includes the Indonesian Sunda Islands, Borneo, and the Philippines. A key to the larval stage of all species is provided.

Two new species of Alainites (Ephemeroptera, Baetidae) from the Mediterranean biodiversity hotspot.

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.

First contribution to Labiobaetis Novikova & Kluge in Cambodia (Ephemeroptera, Baetidae), with description of two new species.

Material collected in 2018 in Cambodia gives us first insights into the diversity of Labiobaetis Novikova & Kluge, 1987 in this country. No species has been reported so far. We identified two new species using a combination of morphology and genetic distance (COI, Kimura 2-parameter). They are described and illustrated based on their larvae. A key to all Labiobaetis species of continental Southeast Asia is provided. The interspecific K2P distance between the two new species is 20-21%, the intraspecific distance of one of them is 1%. The total number of Labiobaetis species worldwide is augmented to 156.

New synonyms and new species of European aquatic dance flies (Diptera, Empididae).

Knowledge of the European aquatic dance flies (Clinocerinae, Hemerodromiinae) is updated. The following new synonyms are proposed: Chelifera pallida Vaillant, 1981 with Chelifera diversicauda Collin, 1927, syn. nov.; Chelifera giraudae Vaillant, 1981 and Chelifera berdeni Vaillant, 1978 (nomen nudum) with Chelifera subangusta Collin, 1961, syn. nov.; Hemerodromia slovenica Horvat & Wagner, 1989 with Hemerodromia laudatoria Collin, 1927, syn. nov.; Hemerodromia maculata Vaillant, 1968 with Hemerodromia unilineata Zetterstedt, 1842, syn. nov.; Wiedemannia aerea Vaillant, 1967 with Wiedemannia hastata (Mik, 1880), syn. nov.; Wiedemannia brevilamellata Wagner, 1985 with Wiedemannia debilis Collin, 1961, syn. nov.; Wiedemannia bilobata Oldenberg, 1910 with Wiedemannia oxystoma (Bezzi, 1905), syn. nov. Lectotypes are designated for Clinocera (Wiedemannia) oxystoma Bezzi, 1905, Wiedemannia aerea Vaillant, 1967, Wiedemannia bilobata Oldenberg, 1910, Philolutra erminea Mik, 1887, Wiedemannia hastata (Mik, 1880), Wiedemannia mirousei Vaillant, 1956 and Phaeobalia pokornyi Mik, 1886. A neotype is designated for Wiedemannia alpina Vaillant, 1953. Wiedemannia rudolfi Wagner & Ivkovic, sp. nov. and Phaeobalia remschakae Wagner sp. nov. are described and figures of male terminalia are provided.

Two new species and two new records of the genus Tenuibaetis Kang & Yang, 1994 (Ephemeroptera: Baetidae) from Indian Himalaya.

As part of ongoing exploration of the mayflies of streams and rivers of Indian Himalayan regions, we describe two new species of the genus Tenuibaetis based on recently collected materials from Western Himalaya viz., Tenuibaetis himani Kubendran, Vasanth & Subramanian sp. nov. and Tenuibaetis kangi Kubendran, Vasanth & Subramanian sp. nov. Additionally, two new records from Eastern Himalaya viz., T. arduus (Kang & Yang, 1994) and T. inornatus (Kang & Yang, 1994) are presented. The biological notes of the stream/rivers are appended. A key to the known Indian species of the genus Tenuibaetis and a distribution maps are provided.

Contribution to the knowledge of the genus Takobia Novikova & Kluge, 1987 (Ephemeroptera, Baetidae) in Central Asia.

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.

New species of Labiobaetis Novikova & Kluge from Southeast Asia and New Guinea (Ephemeroptera, Baetidae).

Material collected between 2006 and 2016 in Borneo, Sulawesi, and New Guinea further increased our knowledge of Labiobaetis Novikova & Kluge in these regions. Five species were previously reported from Borneo, two from Sulawesi, and 33 from New Guinea. Six new species have been identified using a combination of morphology and genetic distance (COI, Kimura 2-parameter), one species from Borneo (Brunei), one from Sulawesi, and four from New Guinea. They are described and illustrated based on their larvae and keys to the species of the relevant groups are provided. Additionally, new reports, a complementary description, and the COI sequence for L.dendrisetis Kaltenbach & Gattolliat are presented. The distribution of Labiobaetis in the Wallacea region is discussed based on the new findings. The total number of Labiobaetis species worldwide is augmented to 153.

A new species and first record of the genus Procerobaetis Kaltenbach & Gattolliat, 2020 (Ephemeroptera, Baetidae) from Thailand.

The genus Procerobaetis Kaltenbach & Gattolliat, 2020 is reported for the first time from Thailand, and Procerobaetis totuspinosus sp. nov. is described as a new species based on larvae. It can be easily distinguished from other known Procerobaetis species by the presence of triangular spines at the posterior margin of tergites VI-IX. COI sequences were obtained from all known species. The genetic distances (Kimura 2-parameter) between the new species and the other species are between 20% and 23%. The morphological characters of the new species and its closely related species are discussed; larval key to all species of the genus Procerobaetis is also provided.

The success story of Labiobaetis Novikova & Kluge in the Philippines (Ephemeroptera, Baetidae), with description of 18 new species.

Material collected between 1994 and 2020 in the Philippines, covering most main islands like Luzon, Mindoro, Palawan, Negros, Cebu, Leyte, and Mindanao and some smaller islands, substantially increased our knowledge of Labiobaetis Novikova & Kluge in this archipelago. Only three species were previously reported: L. molawinensis (Müller-Liebenau, 1982) and L. sumigarensis (Müller-Liebenau, 1982) from larvae and L. boettgeri (Ulmer, 1924) from adults. Eighteen new species have been identified using a combination of morphology and genetic distance (COI, Kimura 2-parameter). They are described and illustrated based on their larvae and a key to all species in the Philippines is provided. The total number of Labiobaetis in the Philippines has increased to 21 species. Additional diversity of Labiobaetis based on molecular evidence only is presented as Molecular Operational Taxonomic Units (MOTUs) without description. The interspecific K2P distances in the Philippines are between 15% and 27%, the intraspecific distances are usually between 0% and 3%. The total number of Labiobaetis species worldwide is augmented to 144.