A new species of Languidipes Hubbard (Ephemeroptera, Polymitarcyidae) from Borneo.

The genus Languidipes is currently represented by three species distributed in southeastern Asia, India, and Sri Lanka. Languidipes corporaali is the most widely distributed species, and both, male and female imagos, as well as nymphs, are known. In contrast, the other species, L. taprobanes and L. lithophagus, are only known from nymphs. Here, we describe a new species, Languidipes janae sp nov, based on male imagos collected from Borneo, Indonesia. This new species is characterized by the presence of ommation on mesonotum, and penis almost completely divided, with sub-quadrate base and a small outer projection basal to the long and slender distal arms. This constitutes the first record of the genus for Borneo. A cladistic analysis of the subfamily Asthenopodinae supports its taxonomic status.

Automated identification of aquatic insects: A case study using deep learning and computer vision techniques.

Deep learning techniques have recently found application in biodiversity research. Mayflies (Ephemeroptera), stoneflies (Plecoptera) and caddisflies (Trichoptera), often abbreviated as EPT, are frequently used for freshwater biomonitoring due to their large numbers and sensitivity to environmental changes. However, the morphological identification of EPT species is a challenging but fundamental task. Morphological identification of these freshwater insects is therefore not only extremely time-consuming and costly, but also often leads to misjudgments or generates datasets with low taxonomic resolution. Here, we investigated the application of deep learning to increase the efficiency and taxonomic resolution of biomonitoring programs. Our database contains 90 EPT taxa (genus or species level), with the number of images per category ranging from 21 to 300 (16,650 in total). Upon completion of training, a CNN (Convolutional Neural Network) model was created, capable of automatically classifying these taxa into their appropriate taxonomic categories with an accuracy of 98.7 %. Our model achieved a perfect classification rate of 100 % for 68 of the taxa in our dataset. We achieved noteworthy classification accuracy with morphologically closely related taxa within the training data (e.g., species of the genus Baetis, Hydropsyche, Perla). Gradient-weighted Class Activation Mapping (Grad-CAM) visualized the morphological features responsible for the classification of the treated species in the CNN models. Within Ephemeroptera, the head was the most important feature, while the thorax and abdomen were equally important for the classification of Plecoptera taxa. For the order Trichoptera, the head and thorax were almost equally important. Our database is recognized as the most extensive aquatic insect database, notably distinguished by its wealth of included categories (taxa). Our approach can help solve long-standing challenges in biodiversity research and address pressing issues in monitoring programs by saving time in sample identification.

Detailed DNA barcoding of mayflies in a small European country proved how far we are from having comprehensive barcode reference libraries.

Mayflies (Ephemeroptera) are among the crucial water and habitat quality bioindicators. However, despite their intensive long-term use in various studies, more reliable mayfly DNA barcode data have been produced in a negligible number of countries, and only ~40% of European species had been barcoded with less than 50% of families covered. Despite being carried out in a small area, our study presents the second-most species-rich DNA reference library of mayflies from Europe and the first comprehensive view from an important biodiversity hotspot such as the Western Carpathians. Within 1153 sequences, 76 morphologically determined species were recorded and added to the Barcode of Life Data System (BOLD) database. All obtained sequences were assigned to 97 BINs, 11 of which were unique and three represented species never barcoded before. Sequences of 16 species with high intraspecific variability were divided into 40 BINs, confirming the presence of cryptic lineages. Due to the low interspecific divergence and the non-existing barcoding gap, sequences of six species were assigned to three shared BINs. Delimitation analyses resulted in 79 and 107 putative species respectively. Bayesian and maximum-likelihood phylogenies confirmed the monophyly of almost all species and complexes of cryptic taxa and proved that DNA barcoding distinguishes almost all studied mayfly species. We have shown that it is still sufficient to thoroughly investigate the fauna of a small but geographically important area to enrich global databases greatly. In particular, the insights gained here transcend the local context and may have broader implications for advancing barcoding efforts.

Indian species of Teloganodes Eaton 1882 (including subgenera Dudgeodes Sartori 2008 and Derlethina Sartori 2008) (Ephemeroptera, Teloganodidae).

According to the classification proposed in the previous publication by Kluge, the genus Teloganodes Eaton 1882 is divided into three subgenera distinguished only by tergalii number: the subgenus Teloganodes (with 5 pairs of tergalii on uromeres II-VI), the subgenus Dudgeodes Sartori in Sartori et al. 2008 (with 4 pairs of tergalii on uromeres II-V) and the subgenus Derlethina Sartori in Sartori et al. 2008 (with 3 pairs of tergalii on uromeres II-IV). All three subgenera are represented in Southern India. Based on the new material, additional descriptions are given to the following species: T. (Teloganodes) kodai Sartori in Sartori et al. 2008 (= Teloganodes barathyae Sivaruban et al. in Martynov et al. 2022, syn. n.); Teloganodes (Teloganodes) dentatus Navás 1932 (= T. sartorii Selvakumar et al. in Selvakumar et al. 2014, syn. n.); Teloganodes (Dudgeodes) palnius (Selvakumar et al. in Selvakumar et al. 2014) (= Dudgeodes bharathidasani Anbalagan et al. 2015, syn. n.; = Dudgeodes sartorii Srinivasan et al. 2021, syn. n.; = Dudgeodes molinerii Sivaruban et al. in Martynov et al. 2022, syn. n.); Teloganodes (Derlethina) tamiraparaniae (Selvakumar et al. in Selvakumar et al. 2014). A new species T. (Teloganodes) velutinus sp. n. is described from the Western Ghats based on larvae, female imagines reared from larvae and eggs.

A new species of Megaglena Peters amp; Edmunds, 1970 (Ephemeroptera: Leptophlebiidae) from Tamil Nadu, India.

Megaglena sivarubani sp. nov. is described based on the nymphs from the Puliyuthu falls of Tamil Nadu, Southern India. The number of species of Megaglena Peters Edmunds is now expanded to three and it is the first record of the genus from the Tamil Nadu part of Southern Western Ghats. Megaglena sivarubani sp. nov. can be distinguished from Indian species M. agasthiya Vasanth, Subramanian Selvakumar by the body size of the nymphs, shape of the labial palp segment III, and by the setation of foretibia. The morphological variations between all the known species of Megaglena are discussed and summarized.

Baetis majus sp. nov., new species of mayfly (Ephemeroptera: Baetidae) from Far East of Russia.

A new species, Baetis majus Tiunova sp. nov., is described and illustrated based on larvae and reared adults discovered in the Russian Far East. The differential identification of this species was determined by the characteristics of other representatives of the genus Baetis Leach, including subgenera Baetis Leach and Tenuibaetis Kang Yang from Eastern and Western Palaearctic, Nearctic and Oriental regions. In addition to morphological studies, DNA barcoding of the described species with average intraspecific K2P distances to nearest neighbours is documented. We reconstructed the phylogenetic relationships of all available cytochrome c oxidase subunit I (COI) sequences of the subgenera of Baetis and Tenuibaetis from four regions. Bayesian analysis using 47 morphological characters additional to partial COI sequences did not allow to determine the species-group of the Baetis genus to which the described species belongs.

A new species of Dudgeodes Sartori, 2008 (Ephemeroptera: Teloganodidae) from Megamalai hills of southern Western Ghats, India.

Dudgeodes sartorii sp. nov. is described based on nymphs from the Megamalai hills of Western Ghats, Southern India. The nymph of Dudgeodes sartorii sp. nov. can be distinguished from other Indian species of Dudgeodes by i) prothorax with two rounded tubercles; (ii) outer margin of mesothorax with simple setae; (iii) distinct maculae in the distal region of femora; (iv) transverse row of setae on fore femora narrower with blunt apex and (v) dark brownish band on the 5th segment of cerci.

A new species of Ephoron Williamson, 1802 (Ephemeroptera: Polymitarcyidae) from Thailand.

The genus Ephoron Williamson, 1802 is widely distributed around the world. In Thailand, only Ephoron indicus Pictet, 1843 was reported in 1961. In this study, a new Ephoron mayfly is described as Ephoron ookaewae sp. nov. In this new species description, the morphological characteristics of larvae and eggs in addition to adults are also shown in detail. Number of tubercles on mandibular tusks, and a median frontal process in larvae, distinguish Ephoron ookaewae sp. nov. from other Ephoron species. Their polar cap shape and a concave indentation in their eggs are also unusual. In addition, the mitochondrial DNA COI sequence data of the newly described Ephoron ookaewae sp. nov. is registered in GenBank. Registration of sequence data for the DNA barcode region of Ephoron mayflies inhabiting the Oriental region remains limited, however it will be useful for future research.

Contribution to the study of Epeorus Eaton, 1881 (Ephemeroptera: Heptageniidae) from India.

Seven species of the genus Epeorus Eaton, 1881 are described so far from India of which redescription is attempted herein for 3 species viz. E. (C.) psi Eaton 1883, E. (E.) gilliesi Braasch 1981, E. (E.) petersi Sivaruban, Venkataraman Sivaramakrishnan 2013 based on the fresh collections. Four species viz., E. (E.) aculeatus Braasch 1990, E. (E.) bifurcatus Braasch Soldán 1979, E. (E.) unicornutus Braasch 2006 and E. (E.) unispinosus Braasch 1980 are new records to this country. Totally, 11 species of the genus Epeorus from India are dealt with herein of which six belongs to the subgenus Epeorus viz. E. (E.) aculeatus Braasch 1990, E. (E.) bifurcatus Braasch Soldán 1979, E. (E.) gilliesi Braasch, 1981 and E. (E.) petersi Sivaruban, Venkataraman Sivaramakrishnan 2013, E. (E.) unispinosus Braasch 1980, E. (E.) unicornutus Braasch 2006 and four to the subgenus Caucasiron viz., E. (C.) kapurkripalanorum Braasch 1983, E. (C.) papillatus Braasch, 2006a, E. (C.) psi Eaton 1883 which larva is described in details for the first time and E. (C.) suspicatus Braasch, 2006b . The subgeneric status of E. lahaulensis Kapur Kripalani 1963 cannot be fixed due to non-availability of larval description. A dichotomous key to the larvae of available species in India is presented. Distribution of subgenera and species within India is discussed.

A description of the second species of the genus Bleptus Eaton, 1885 (Ephemeroptera: Heptageniidae) from Japan, and phylogenetic relationships of two Bleptus mayflies inferred from mitochondrial and nuclear gene sequences.

A new mayfly species, Bleptus michinokuensis sp. nov. (Ephemeroptera: Heptageniidae) is described on the basis of specimens of male and female adults and mature nymphs collected at a seepage zone of a small freshwater branch of the 'Tachiya-zawa-gawa' River located amongst the northern foothills of Mt. Gassan (Shonai-machi Town, Yamagata Prefecture, Japan). This new Bleptus species is characterized by its clear fore and hind wings. That is, they neither exhibit the distinct black band on the fore wings, nor the characteristic darkened margins along the edges of both the fore and hind wings. Rather it has a blackish colored terminal half of its fore legs (i.e., tibial, tarsal and pretarsal segments). These features differ clearly when comparing them to the other known species, Bleptus fasciatus Eaton. The information and data describing the habitat and distribution range of this new species are also noted. We also examined and discussed the genetic relationship of two Bleptus mayflies to settle the taxonomic status, inferred from the partially sequenced cytochrome c oxidase subunit I (COI) and large mitochondrial ribosomal subunit (16S rRNA) genes, and also the nuclear internal transcribed spacer 2 (ITS2) gene sequences. Consequently, phenetic and molecular phylogenetic analyses agreed well in terms of clustering.

A new species of Caenis Stephens, 1835 (Ephemeroptera: Caenidae) from Tamil Nadu, Southern India.

A new mayfly species Caenis maduraiensis sp. nov. is described and illustrated from nymph and adults collected from lentic habitat around Madurai. The nymph can be distinguished by the following characters: anterior margin of labrum with row of bipectinate setae longer laterally and a group of highly fringed setae behind emargination; and hind claw long, slender and hooked with row of denticles. Adults are characterized by prosternal triangle with slightly concave sides, tip acutely pointed; apical part of forceps abruptly narrowed to the tip, with a long apical spine, and few trichomes on surface.

Mayfly taxonomy (Arthropoda: Hexapoda: Ephemeroptera) during the first two decades of the twenty-first century and the concentration of taxonomic publishing.

The twentieth anniversary of the first issue of Zootaxa (De Moraes Freire, 2001) provides an appropriate opportunity to reflect on some trends in global Ephemeroptera taxonomy publishing over the last two decades, with a focus on the description of new species and the outsized role of the journals Zootaxa and ZooKeys, in particular. Detailed reviews of world Ephemeroptera knowledge up to about 2000 were collected in a series of nine papers from a symposium on the subject, published together in the proceedings of the ninth International Conference on Ephemeroptera (Domínguez 2001). Domínguez Dos Santos (2014) provided updates and analysis for South America up to the year 2012. More recent detailed accounts of regional and taxonomic diversity, and other aspects of mayfly biology and ecology, were reviewed by Jacobus et al. (2019), while Ogden et al. (2019) discussed current issues involving higher classification.

Overview of Indian Hyrtanellini (Ephemeroptera: Ephemerellidae), with new species and records from related regions.

The Hyrtanellini (Ephemeroptera: Ephemerellidae: Ephemerellinae) from India and related regions are reviewed, including three new species viz., Serratella palatovi Martynov, Selvakumar Jacobus, sp. nov., Torleya simbalbarensis Selvakumar, Subramanian, Martynov Jacobus, sp. nov., and Torleya dibruensis Selvakumar, Martynov Jacobus, sp. nov.; and first country records of Teloganopsis jinghongensis (Xu, You Hsu, 1984) and Hyrtanella grandipennis (Zhou, Su Gui, 2000). Description of Serratella palatovi sp. nov. is based on material from Thailand, India and Nepal; Torleya simbalbarensis sp. nov. and Torleya dibruensis sp. nov. are described based on material from India. For now, the tribe Hyrtanellini in India comprises eight species from the genera Serratella Edmunds, 1959, Torleya Lestage, 1917, Teloganopsis Ulmer, 1939 and Hyrtanella Allen Edmunds, 1976. Additional records of Teloganopsis jinghongensis from Thailand, Torleya nepalica (Allen Edmunds, 1963) and Torleya coheri (Allen Edmunds, 1963) from Nepal also are provided here. All Indomalayan Hyrtanellini species are discussed to some extent.

Description of a new species, nymphs of two known species and a new record of Miroculis/ Edmunds, 1963 (Ephemeroptera: Leptophlebiidae) from Brazil.

Miroculis is one of the most diversified Neotropical genera of Leptophlebiidae in South America with 26 species currently known. In this work we describe a new species of Miroculis based on imagos from Amazonas, and the unknown nymphs of Miroculis (Miroculis) caparaoensis and Miroculis (Ommaethus) misionensis, both associated with imagos. In addition, Miroculis (Ommaethus) misionensis is recorded for the first time from Brazil.

Complete mitochondrial genomes of Epeorus carinatus and E. dayongensis (Ephemeroptera: Heptageniidae): Genomic comparison and phylogenetic inference.

The current research on Ephemeroptera is mainly based on its morphology, since only small numbers of mitogenomes have been reported. In this study, the mitogenomes of Epeorus carinatus (15,338 bp) and E. dayongensis (15,609 bp) were sequenced, annotated and compared to genome data from congeners. Both mitogenomes had 23 tRNA genes including standard 22 and one extra tRNAMet. The duplicated tRNAMet gene had been found in other heptageniid species except Paegniodes cupulatus, suggesting it could be used as a molecular synapomorphy for partial Heptageniidae. The phylogenetic analyses based on Bayesian Inference (BI) and Maximum Likelihood (ML) showed that Heptageniidae was monophyletic and the relationships among known Epeorus species were ((E. carinatus + E. herklotsi) + (E. dayongensis + E. sp. 1)), which implied the focal species E. carinatus and E. dayongensis should be grouped into different subgenera.

Unmasking a gap: A new oligoneuriid fossil (Ephemeroptera: Insecta) from the Crato Formation (upper Aptian), Araripe Basin, NE Brazil, with comments on Colocrus McCafferty.

The Crato Formation (Araripe Basin) preserves one of the most diverse entomofaunas of the Cretaceous. Among the groups of insects, mayflies stand out in abundance, but among them oligoneuriids are especially rare. A newly discovered adult oligoneuriid from this unit is here described as Incogemina nubila gen. et sp. nov. and new subfamily Incogemininae. A phylogenetic analysis recovered the new taxon as the sister group to the species-rich and cosmopolitan Oligoneuriinae. The paratype of Colocrus indivicum, described as an "oligoneuriid" from the same unit, is here reviewed and considered as belonging to the family Hexagenitidae. The biogeographical and taxonomic implications of this discovery and the phylogenetic position of Incogemina nubila are discussed. Incogemina bridge an important morphological gap between the Oligoneuriinae and the extant Chromarcys. Also, it demonstrates that the divergence between Oligoneuriinae and Incogemininae probably occurred in South America.

Cymbalcloeon gen. nov., an incredible new mayfly genus (Ephemeroptera: Baetidae) from Thailand.

The genus Cymbalcloeon gen. nov. (Ephemeroptera: Baetidae) is established for a new species Cymbalcloeon sartorii sp. nov. from Thailand, based on larval stage. This genus is unique among all of the Baetidae by the presence of three pairs of single gills on segments V-VII, ventrally oriented to cover the sterna VI-IX. Cymbalcloeon sartorii gen. nov. et sp. nov. presents unique or rare morphological characters such as a deeply concave margin between the prostheca and mola, without setae; a very large subtriangular process of the left mandible; a maxillary palp segment II with scarce and very long setae; almost completely fused labial palp segments II and III with numerous very long setae; elongate tarsal claw with two rows of teeth; a shagreen surface of the terga and paraproct; and a very reduced body size. The gills of the new genus move very quickly during respiration and present a near-synchronous protraction. Due to the very derived larval morphological character and the unknown imaginal stage, the exact phylogenetic position of the genus remains unclear; it most certainly belongs to the concept of Anteropatellata and is possibly closely related to the genus Baetopus.

Genomic adaptations to aquatic and aerial life in mayflies and the origin of insect wings.

The evolution of winged insects revolutionized terrestrial ecosystems and led to the largest animal radiation on Earth. However, we still have an incomplete picture of the genomic changes that underlay this diversification. Mayflies, as one of the sister groups of all other winged insects, are key to understanding this radiation. Here, we describe the genome of the mayfly Cloeon dipterum and its gene expression throughout its aquatic and aerial life cycle and specific organs. We discover an expansion of odorant-binding-protein genes, some expressed specifically in breathing gills of aquatic nymphs, suggesting a novel sensory role for this organ. In contrast, flying adults use an enlarged opsin set in a sexually dimorphic manner, with some expressed only in males. Finally, we identify a set of wing-associated genes deeply conserved in the pterygote insects and find transcriptomic similarities between gills and wings, suggesting a common genetic program. Globally, this comprehensive genomic and transcriptomic study uncovers the genetic basis of key evolutionary adaptations in mayflies and winged insects.

The impact of Miocene orogeny for the diversification of Caucasian Epeorus (Caucasiron) mayflies (Ephemeroptera: Heptageniidae).

A common hypothesis for the high biodiversity of mountains is the diversification driven by orogeny creating conditions for rapid in situ speciation of resident lineages. The Caucasus is a young mountain system considered as a biodiversity hotspot; however, the origin and evolution of its diversity remain poorly understood. This study focuses on mayflies of the subgenus Caucasiron, one of the most diversified stenotopic mayflies inhabiting various types of streams throughout the Caucasus. Using the time-calibrated phylogeny based on two mitochondrial (COI, 16S) and three nuclear (EF-1α, wg, 28S) gene fragments, we tested the role of Caucasian orogeny in biogeography, diversification patterns, and altitudinal diversification of Caucasiron mayflies. We found that orogeny promoted the lineage diversification of Caucasiron in the Miocene. The highest diversification rate corresponding with the uplift of mountains was followed by a significant slowdown towards the present suggesting minor influence of Pleistocene climatic oscillations on the speciation. The Caucasiron lineages cluster into three principal clades originating in the Upper Miocene. We found a strong support that one of the three clades diversified via allopatric speciation in the Greater Caucasus isolated in the Parathetys Sea. The other two clades originating most likely outside the Greater Caucasus diversified towards high and low altitude, respectively, indicating possible role of climatic factors and/or passive uplift on their differentiation. Current high Caucasiron diversity in the Greater Caucasus is a result of in situ speciation and later immigration from adjacent mountain ranges after the Parathetys Sea retreat. Our phylogeny supported the monophyly of Rhithrogeninae, Epeorus s.l., Caucasiron, and Iron. Epeorus subgenus Ironopsis was found paraphyletic, with its European representatives more closely related to Epeorus s.str. than to Iron. Therefore, we re-arranged taxa treated within Ironopsis to comply with the phylogeny recovered herein.

Diversity of EPT (Ephemeroptera, Plecoptera, Trichoptera) Along Streams Fragmented by Waterfalls in the Brazilian Savanna.

In stream ecosystems, waterfalls intercept the fluvial continuum and limit the dispersion of aquatic organisms. However, the barrier effect may be minimized or absent for insects whose life cycle is not restricted to the aquatic environment (i.e., winged adults), such as the orders Ephemeroptera, Plecoptera and Trichoptera (EPT). In this study, we investigated EPT diversity (abundance, richness, and composition) in savanna headwater streams (Cerrado Domain, Brazil) to investigate the hypothesis that large waterfalls have little effect on instream assemblage structure. During 2017 and 2018, we sampled EPTs and measured environmental conditions at reaches adjacent (downstream and upstream) to waterfalls (5 to 70 m high). We collected 2532 immature specimens of 33 genera, including the first record of 14 genera of Ephemeroptera, 11 Trichoptera, and three Plecoptera for the Tocantins State. Hydro-geomorphic and streambed conditions varied among sites, but they were not related to the presence of waterfalls. Assemblage structure was similar between downstream and upstream reaches, with no significant difference in taxa richness, abundance, and composition. This pattern was consistently observed considering all data combined, and each order separately. These results support the hypothesis that physical barriers have weak effects on EPT assemblages at small spatial scales, where strong dispersal and habitat similarity probably homogenizes the structure of local assemblages in stream corridors adjacent to large waterfalls. The study provides important information about factors driving the distribution of biodiversity in savanna streams, which are relevant to support conservation and management plans in the Brazilian Cerrado.