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The poorly known, so called widely distributed and highly varying species of the European Rhyacophila fasciata species complex are revised by fine phenomics of the paramere organisation. In this species complex paramere is the most diverse organ. It is the speciation trait integrating the initial split of speciation by its stimulatory and titillating function involved in the early processes of reproductive isolation. Based on paramere organisation and on the character state of distribution three lineages have been delineated in the Rhyacophila fasciata species complex: the European R. fasciata lineage, the Caucasian R. aliena lineage and the R. mysica lineage distributed from Albania to Pakistan. In the R. fasciata lineage we have distinguished three clades of species: R. fasciata with five species, R. matrensis with seven species, and R. denticulata with seven species. We have re-diagnosed three known species: R. fasciata Hagen, 1859, R. denticulata McLachlan, 1879, R. sociata Navas, 1916 and described 15 species new to science: R. biharensis Oláh sp. nov., R. bulgarica Oláh sp. nov., R. coppai Oláh sp. nov., R. csornahorensis Oláh & Szczęsny sp. nov., R. ferda Oláh sp. nov., R. kopasa Oláh & Coppa sp. nov., R. matrensis Oláh, & Szczęsny sp. nov., R. retezatensis Oláh sp. nov., R. rova Oláh & Coppa sp. nov. R. ruda Oláh & Johanson sp. nov., R. salfa Oláh sp. nov., R. soreda Coppa & Oláh sp. nov. R. suna Oláh sp. nov., R. tuhega Oláh sp. nov., R. zemplenensis Oláh sp. nov. The species status of Rhyacophila gemella Navas, 1923 was reinstated.

Dytiscus latissimus (Coleoptera Dytiscidae) is an endangered diving beetle throughout its range. It is one of the two species of Dytiscidae listed in Annex II of the Habitats Directive, IUCN red list and in many national level legislations and therefore strictly protected. The conservation of endangered species first of all requires an assessment of their population size. Until now, a method has not been developed for estimating the size of D. latissimus populations. The article summarizes the results of two studies carried out independently in Germany and Latvia. Both studies were carried out in one water body used recapture method but with a different spatial placement of traps, which, according to our data, is an important factor in population estimation. We evaluated Jolly-Seber and Schnabel approaches of estimating aquatic beetle's populations and found that confidence intervals obtained by different methods in our research do not differ significantly, but combination of both models provide the most accurate estimates of population dynamics. As part of the study, we concluded that the populations of Dytiscus latissimus are relatively closed, so we accept that the Schnabel estimate shows more accurate data. By fixing the places of capture of each individual, it was found that females live mainly locally, and males actively move within the water body. This aspect indicates the advantage of the spatial placement of traps compared to the use of transects. The results of our study show a significantly higher number of both captured and recaptured males Such a sex ratio may indicate both a greater activity of males and differences in the sex ratio in the population. The study confirmed that environmental changes, such as the water level in a water body, can also significantly affect the result of a population assessment. In the frame of D. latissimus monitoring, to obtain an objective estimation of the species population size we recommend using four traps for each 100 m of water body shoreline with 4–8 censuses, dependently on the recapture rate. [ABSTRACT FROM AUTHOR]

We here describe Liodessus lacunaviridis sp. n. (Coleoptera: Dytiscidae, Bidessini), collected from small mossy puddles at the edge of the Laguna Verde, Boyaca, Colombia. Within Liodessus Guignot, 1939 the new species is well characted by its darker coloration, more elongate oval habitus, and the shape of the median lobe in ventral view, which is more evenly narrowing than in the other Andean species known so far. In addition to external morphology, we used mitochondrial cox1 sequence data to support the generic assignment and delineate the new species. Altogether 32 species of the genus are now known from the Americas, 12 of them from the Andean region. [ABSTRACT FROM AUTHOR]

Abstract Background The Pleistocene Ice Ages were the most recent geohistorical event of major global impact, but their consequences for most parts of the Southern hemisphere remain poorly known. We investigate a radiation of ten species of Sternopriscus, the most species-rich genus of epigean Australian diving beetles. These species are distinct based on genital morphology but cannot be distinguished readily by mtDNA and nDNA because of genotype sharing caused by incomplete lineage sorting. Their genetic similarity suggests a Pleistocene origin. Results We use a dataset of 3858 bp of mitochondrial and nuclear DNA to reconstruct a phylogeny of Sternopriscus using gene and species trees. Diversification analyses support the finding of a recent rapid speciation event with estimated speciation rates of up to 2.40 species per MY, which is considerably higher than the proposed average rate of 0.16 species per MY for insects. Additionally, we use ecological niche modeling and analyze data on habitat preferences to test for niche divergence between species of the recent Sternopriscus radiation. These analyses show that the species can be characterized by a set of ecological variables referring to habitat, climate and altitude. Conclusions Our results suggest that the repeated isolation of populations in glacial refugia might have led to divergent ecological adaptations and the fixation of morphological traits supporting reproductive isolation and therefore may have promoted speciation. The recent Sternopriscus radiation fulfills many characteristics of a species flock and would be the first described example of an aquatic insect species flock. We argue that the species of this group may represent a stage in speciation past the species flock condition because of their mostly broad and often non-overlapping ranges and preferences for different habitat types.

A comprehensive revision is presented of the Oriental and Australasian diving beetle genus Sandracottus Sharp, 1882 (Coleoptera: Dytiscidae: Dytiscinae: Aciliini) and seven junior subjective synonyms are proposed. Sandracottusguerini Balfour-Browne, 1939, syn. nov. is a junior subjective synonym of S.femoralis Heller, 1934; S.manipurensis Vazirani, 1969, syn. nov. of S.hunteri (Crotch, 1872); S.mixtus Blanchard, 1843, syn. nov. of S.chevrolati (Aubé, 1838); and S.angulifer Heller, 1934, syn. nov. , S.nauticus Sharp, 1882, syn. nov. , and S.palawanensis Satô, 1978, syn. nov. of S.maculatus (Wehncke, 1876). Finally, S.vijayakumari Anand et al., 2021, syn. nov. is a new synonym of S.dejeanii (Aubé, 1838). New status is assigned to S.bakewelliiguttatus (Sharp, 1882), stat. nov. as well as S.hunteri (Crotch, 1872), stat. rev. Lectotypes are designated for the following taxa: Dytiscusflavocinctus Guérin-Méneville, 1830, Hydaticuschevrolati Aubé, 1838, Hydaticusinsignis Wehncke, 1876, Sandracottusbaeri Régimbart, 1899, Sandracottusbizonatus Régimbart, 1899, and Sandracottusornatus Sharp, 1882. A neotype is designated for Hydaticusmaculatus Wehncke, 1876. In total, three Oriental species, two of which also occur in the East Palaearctic, six Southeast Asian species, one species from New Guinea and the Moluccas, and one from Australia with an endemic subspecies in Central Australia ( S.bakewelliiguttatus ) are recognised. Each taxon is presented with a diagnosis, habitat preferences, conservation assessments, distribution data, and a comprehensive bibliography. Important characters (habitus, dorsal colouration, median lobes and parameres) are illustrated. All currently valid taxa are redescribed. Sandracottusjaechi Wewalka & Vazirani, 1975 from Sri Lanka, S.bizonatus from Borneo, S.insignis from the Philippines and S.rotundus Sharp, 1882 from Sulawesi are recommended to be listed in the next IUCN red data book. A key to all species is provided., Competing Interests: The authors have declared that no competing interests exist., (Lars Hendrich, Michel Brancucci.)

Here, we review the taxonomy and population genetic structure of diving beetles in the genus Liodessus Guignot, 1939 from the high Andes of southern Colombia and Ecuador. Liodessus quillacinga ecuadoriensis ssp. nov. is described from the type locality Otavalo, Laguna San Pablo. Liodessus quimbaya azufralis Megna, Hendrich & Balke, 2019 stat. nov. is now regarded as a subspecies of Liodessus quimbaya Megna, Hendrich & Balke, 2019 based on new morphological and genetical data. Liodessus quimbaya paletara ssp. nov. is described from the Paletará Valley (Colombia: Cauca)., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Balke et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Disjunct distributions, characterised by spatially separated populations of related species, offer insights into historical biogeographic patterns and evolutionary processes. This study investigates the evolutionary history of the diving beetle subfamily Lancetinae through a phylogenomic approach incorporating ultraconserved elements (UCEs) and heritage genetic markers. Our findings support an early Miocene origin for Lancetinae, with subsequent diversification influenced by historical vicariance events and long-distance dispersal. The divergence from the closely related subfamily Coptotominae in the late Cretaceous is not consistent with a Gondwanan origin, although highlights a likely Pangean origin for these taxa. This research underscores the significant impact of Gondwanan fragmentation on biogeographic patterns and highlights the remarkable dispersal capabilities of Lancetinae beetles., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The Pleidae, or pygmy backswimmers, is a family of aquatic bugs (Hemiptera, Heteroptera, Nepomorpha) containing four genera. Here, we describe Plea cryptica sp. nov. and redescribe its sister species, Plea minutissima Leach, 1817. Whereas the morphological distinction of these closely related species is only possible for males, molecular data clearly separate them. As part of our taxonomic study, we provide comprehensive molecular data including more than 200 DNA barcodes from all over Europe, complete nuclear ribosomal DNA, full mitochondrial genome data, and 3D scans for both species. Furthermore, the same molecular markers are also presented for Neoplea striola (Fieber, 1844). We used Maximum Likelihood (ML) analyses to reconstruct the phylogeny of the Pleidae and Notonectoidea based on available mitogenomic data. Our study represents a successful implementation of the proposed concept of taxonomics, using data from high-throughput sequencing technologies for integrative taxonomic studies, and allowing high confidence for both biodiversity and ecological research., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Understanding the profound influence of climatic and tectonic histories on adaptation and speciation is a crucial focus in biology research. While voyages like Humboldt's expedition shaped our understanding of adaptation, the origin of current biodiversity remains unclear - whether it arose in situ or through dispersal from analogous habitats. Situated in the geologically complex Australopacific region, our study focuses on Limbodessus diving beetles (Dytiscidae), a diverse genus distributed from underground aquifers in Western Australia to alpine meadows in New Guinea. Using low-coverage whole-genome sequencing, we established a time-calibrated phylogenetic tree, elucidating Limbodessus' origin in the mid-late Miocene, most likely in the Sahul continent (i.e., Australia and New Guinea) and western Pacific archipelagos. Our results provide evidence for parallel colonization and speciation at extreme altitudinal ends, driven by aridification in Australia, influencing subterranean colonization, and in situ diversification of alpine taxa by passive-uplifting of local biota in New Guinea. Furthermore, our findings highlight instances of subterranean speciation in isolated underground aquifers, marked by recurrent independent colonizations of this habitat., Competing Interests: Competing interests The authors declare no competing interest., (© 2024. The Author(s).)

The Austrelatuspapuensis group is the second species group of the New Guinean representatives of the recently described genus Austrelatus Shaverdo et al., 2023. The group is mainly defined by distinct scale- and/or spinula-like surface structures of the dorsal sclerite of the median lobe. The species group already contains four described species and 42 new species and one subspecies treated here: Austrelatusaiyurensis sp. nov. , A.asteios sp. nov. , A.bewaniensis sp. nov. , A.bosaviensis sp. nov. , A.bundunensis sp. nov. , A.centralensis sp. nov. , A.craterensis sp. nov. , A.decoris sp. nov. , A.dekai sp. nov. , A.epicharis sp. nov. , A.flavocapitatus sp. nov. , A.fuscus sp. nov. , A.herzogensis sp. nov. , A.inconstans sp. nov. , A.iriatoi sp. nov. , A.kalibumi sp. nov. , A.kebarensis sp. nov. , A.kokodensis sp. nov. , A.leptos sp. nov. , A.loloki sp. nov. , A.lopintolensis sp. nov. , A.madangensis sp. nov. , A.maindai sp. nov. , A.mamberamo sp. nov. , A.mianminensis sp. nov. , A.miltokarenos sp. nov. , A.noiadi sp. nov. , A.normanbyensis sp. nov. , A.ohu sp. nov. , A.posmani sp. nov. , A.procerus sp. nov. , A.pseudogestroi sp. nov. , A.pseudomianminensis sp. nov. , A.robustus sp. nov. , A.sararti sp. nov. , A.sumokedi sp. nov. , A.wanangensis sp. nov. , A.wasiorensis sp. nov. , A.wasurensis sp. nov. , A.weigeli sp. nov. , A.yamurensis sp. nov. , A.yeretuar sp. nov. , A.xanthocephalusnabirensis ssp. nov. A checklist and identification key to New Guinean species of the group are provided and important diagnostic characters are illustrated. Data on the species distributions and habiat preferences are given., Competing Interests: The authors have declared that no competing interests exist., (Helena Shaverdo, Lars Hendrich, Suriani Surbakti, Rawati Panjaitan, Michael Balke.)

Limbodessus moni sp. nov. is described from Lake Anderson and from small, richly vegetated swampy areas around alpine lakes at 3,970 m a.s.l. near the Grasberg Mine (Carstensz Pyramid) in the Central Mountain Range of New Guinea. The record of the new species marks the altitudinal maximum of a diving beetle in New Guinea. The new species is morphologically similar to L. alexanderi Balke & Hendrich, 2015 in terms of body size and dark coloration; however, both species can be easily separated by the shape of the median lobe and the more moniliform female antennomeres, not forming a conspicuous club as in L. alexanderi. A modified key for all five Limbodessus species from New Guinea and adjacent islands is presented.

Herein, Austrelatus gen. nov. (type species: Copelatusirregularis W.J. Macleay, 1871) is described for a distinctive lineage of predominantly Australasian species previously assigned to Copelatus Erichson, 1832. The new genus was retrieved as well supported, monophyletic clade in phylogenetic analysis of DNA sequences data using Bayesian and parsimony approaches. The main morphological diagnostic character of Austrelatus is a complex median lobe of the aedeagus, with evident dorsal and ventral sclerites usually divided in apical half into two lobes of different shape or otherwise modified. Morphological comparison of the new genus with other Copelatinae genera, especially with Copelatus and Exocelina Broun, 1886, and a generic key to the New Guinean Copelatinae are provided. New combinations are established for 31 already described species mainly from the Australian Region (all from Copelatus (Megna, Atthakor, Manaono, Hendrich & Balke, 2017), Austrelatusadelbert (Megna, Atthakor, Manaono, Hendrich & Balke, 2017), comb. nov. ; A.badeni (Sharp, 1882), comb. nov. ; A.bakewelli (J. Balfour-Browne, 1939), comb. nov. (Hájek, Shaverdo, Hendrich & Balke, 2021), A.baranensis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov. (Hájek, Shaverdo, Hendrich & Balke, 2021), A.bougainvillensis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov. (Hendrich & Balke, 1998), A.boukali (Hendrich & Balke, 1998), comb. nov. ; A.clarki (Sharp, 1882), comb. nov. ; A.daemeli (Sharp, 1882), comb. nov. ; A.davidi (Wewalka, 2017), comb. nov. ; A.deccanensis (Sheth, Ghate & Hájek, 2018), comb. nov. ; A.fidschiensis (Zimmermann, 1928), comb. nov. ; A.gestroi (Régimbart, 1892), comb. nov. ; A.irregularis (W.J. Macleay, 1871), comb. nov. ; A.kaszabi (Guignot, 1956), comb. nov. (Hájek, Shaverdo, Hendrich & Balke, 2021), A.kietensis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov. (Hájek, Shaverdo, Hendrich & Balke, 2021), A.laevipennis (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov. ; A.luteomaculatus (Guignot, 1956), comb. nov. ; A.maushomi (Sheth, Ghate & Hájek, 2018), comb. nov. ; A.neoguineensis (Zimmermann, 1919), comb. nov. ; A.nigrolineatus (Sharp, 1882), comb. nov. ; A.papuensis (J. Balfour-Browne, 1939), comb. nov. ; A.parallelus (Zimmermann, 1920a), comb. nov. (Hendrich & Balke, 1998), A.schuhi (Hendrich & Balke, 1998), comb. nov. (Hájek, Hendrich, Hawlitschek & Balke, 2010), A.sibelaemontis (Hájek, Hendrich, Hawlitschek & Balke, 2010), comb. nov. ; A.strigosulus (Fairmaire, 1878), comb. nov. ; A.ternatensis (Régimbart, 1899), comb. nov. (Hendrich & Balke, 1995), A.uludanuensis (Hendrich & Balke, 1995), comb. nov. (Hájek, Shaverdo, Hendrich & Balke, 2021), A.urceolus (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov. (Hájek, Shaverdo, Hendrich & Balke, 2021), A.variistriatus (Hájek, Shaverdo, Hendrich & Balke, 2021), comb. nov. ; A.wallacei (J. Balfour-Browne, 1939), comb. nov. and A.xanthocephalus (Régimbart, 1899), comb. nov. Austrelatus species from New Guinea are divided into two informal species groups, the A.neoguineensis group and A.papuensis group, and A.fumato sp. nov. and A.setiphallus sp. nov. standing aside of them. The A.neoguineensis group is introduced with three previously known species and 29 new species described here based on the morphological characters and Cox1 data: Austrelatusbaliem sp. nov. , A.bormensis sp. nov. , A.brazza sp. nov. , A.debulensis sp. nov. , A.fakfak sp. nov. , A.febrisauri sp. nov. , A.fojaensis sp. nov. , A.garainensis sp. nov. , A.innominatus sp. nov. , A.lembenensis sp. nov. , A.lisae sp. nov. , A.manokwariensis sp. nov. , A.mimika sp. nov. , A.mirificus sp. nov. , A.moreguinensis sp. nov. , A.nadjae sp. nov. , A.oksibilensis sp. nov. , A.pseudoneoguineensis sp. nov. , A.pseudoksibilensis sp. nov. , A.rajaampatensis sp. nov. , A.rouaffer sp. nov. , A.rugosus sp. nov. , A.sandaunensis sp. nov. , A.sarmiensis sp. nov. , A.securiformis sp. nov. , A.testegensis sp. nov. , A.toricelli sp. nov. , A.vagauensis sp. nov. , and A.wanggarensis sp. nov. Copelatusvagestriatus Zimmermann, 1919, syn. nov. is recognised as a junior subjective synonym of A.clarki (Sharp, 1882). The lectotypes of Copelatusgestroi Régimbart, 1892, C.neoguineensis Zimmermann, 1919 and C.xanthocephalus Régimbart, 1899 are designated. All species are (re)described, and their important species characters (genitalia, habitus, and colour patterns) are illustrated. Keys to all species are provided. The known distribution and habitat preferences of each species are outlined briefly. New Guinean Austrelatus occupy a variety of stagnant water habitats, either lentic sensu stricto , or standing water associated with lotic habitats (e.g., backflows, rockpools, intermittent / ephemeral stream pools)., Competing Interests: The authors have declared that no competing interests exist., (Helena Shaverdo, Jiří Hájek, Lars Hendrich, Suriani Surbakti, Rawati Panjaitan, Michael Balke.)

We studied Liodessus diving beetles from six eastern Colombian Páramo areas, as well as from the Altiplano. We discovered a highly characteristic new species, based on male genital morphology, Liodessussantarosita sp. nov. , in the Páramo de Guantiva-Rusia. Specimens from the Altiplano around Bogotá, and the Páramos of Almorzadero, Chingaza, Matarredonda, Rabanal y Rio Bogotá and Sumapaz form one clade of genetically similar populations based on mitochondrial Cox1 sequence data. The individuals of this clade are sub-structured according to their geographic distribution. The populations differ from each other mainly in terms of body size and coloration and, at most, subtly in their genital morphology. In two cases, we find putative hybrid populations between Altiplano and Páramo areas. We suggest that the different Páramo populations are in an early phase of speciation, and perhaps already genetically isolated in some cases. They are here assigned subspecies status to highlight these ongoing processes pending more comprehensive geographic sampling and use of genomic data. We refer to this clade as the Liodessusbogotensis complex, containing Liodessusb.bogotensis Guignot, 1953; Liodessusb.almorzadero ssp. nov. ; Liodessusb.chingaza ssp. nov. ; Liodessusb.lacunaviridis Balke et al., 2021, stat. nov. ; Liodessusb.matarredonda ssp. nov. , and Liodessusb.sumapaz ssp. nov., (Michael Balke, Katja Neven, Adrián Villastrigo, Rodulfo Ospina-Torres, Carlos Prieto, Nicolas Gutierrez Rubiano, Ingrid Lotta, Luisa F. Dueñas, Lars Hendrich.)

The diving beetle Clypeodytes limpidus sp. nov. is described from western Yunnan, China. It is the second known species of the genus Clypeodytes Rgimbart, 1894 from China and belongs to the subgenus Hypoclypeus Guignot, 1950. It can be distinguished from C. bufo (Sharp, 1890), the only other Chinese Clypeodytes species, by the shape of the median lobe, the more rounded body and the elytral pattern. A Chinese specimen of C. bufo is illustrated, and the species is recorded for the first time for Laos.

Liodessuspicinus sp. nov. is described from the Páramo de Sumapaz near Bogota D.C. at 3,500 m above sea level. The species can be distinguished from the other Colombian Liodessus species by its dark coloration, discontinuous habitus, shiny surface of the pronotum and elytron, presence of a distinct occipital line, distinct basal pronotal striae, short or even faint basal elytral striae, as well as by its distinct geographic distribution and cox1 signature., (Michael Balke, Yoandri Suarez-Megna, Rodulfo Ospina-Torres, Juan Simon Venegas, Carlos Prieto, Lars Hendrich.)

Bidessus migrator Sharp, 1882, so far assigned to Clypeodytes Régimbart, 1894, and widely distributed in Australia and New Guinea, is re-described. Based on morphological and molecular evidence, it is here transferred to Leiodytes Guignot, 1936. Bidessus loriae Régimbart, 1892 is found to be a junior subjective synonym of L. migrator. We describe the following new species: Leiodytes surianiae sp. nov. (eastern New Guinea, northeast coast of Queensland), and Leiodytes wattsi sp. nov. (southern New Guinea and Darwin area to northern Queensland). We delineate the species using characters such as male genital structure and beetle size, shape and color pattern. Mitochondrial Cox1 data for 27 individuals, representing all three Australasian species, were generated and revealed clusters congruent with the morphological evidence. In Australia Leiodytes only occurs in the tropical and subtropical northern part of the continent. None of the species is endemic to Australia. The species are mainly lentic, occurring in seasonal swamps, flooded meadows and pools of intermittent rivers and temporary creeks.

Background: Dragonflies and damselflies (Odonata) are important components in biomonitoring due to their amphibiotic lifecycle and specific habitat requirements. They are charismatic and popular insects, but can be challenging to identify despite large size and often distinct coloration, especially the immature stages. DNA-based assessment tools rely on validated DNA barcode reference libraries evaluated in a supraregional context to minimize taxonomic incongruence and identification mismatches., Methods: This study reports on findings from the analysis of the most comprehensive DNA barcode dataset for Central European Odonata to date, with 103 out of 145 recorded European species included and publicly deposited in the Barcode of Life Data System (BOLD). The complete dataset includes 697 specimens (548 adults, 108 larvae) from 274 localities in 16 countries with a geographic emphasis on Central Europe. We used BOLD to generate sequence divergence metrics and to examine the taxonomic composition of the DNA barcode clusters within the dataset and in comparison with all data on BOLD., Results: Over 88% of the species included can be readily identified using their DNA barcodes and the reference dataset provided. Considering the complete European dataset, unambiguous identification is hampered in 12 species due to weak mitochondrial differentiation and partial haplotype sharing. However, considering the known species distributions only two groups of five species possibly co-occur, leading to an unambiguous identification of more than 95% of the analysed Odonata via DNA barcoding in real applications. The cases of small interspecific genetic distances and the observed deep intraspecific variation in Cordulia aenea (Linnaeus, 1758) are discussed in detail and the corresponding taxa in the public reference database are highlighted. They should be considered in future applications of DNA barcoding and metabarcoding and represent interesting evolutionary biological questions, which call for in depth analyses of the involved taxa throughout their distribution ranges., Competing Interests: Jérôme Morinière is founder & CEO of AIM Advanced Identification Methods GmbH. All authors declare that they have no competing interests., (© 2021 Geiger et al.)

The first account of the genus Copelatus Erichson, 1832 in the Solomon Islands is provided, reporting 10 species for the Archipelago. Six of these are new to science: C. baranensis sp. nov. , C. laevipennis sp. nov. , C. urceolus sp. nov. , and C. variistriatus sp. nov. from Guadalcanal and C. bougainvillensis sp. nov. , and C. kietensis sp. nov. from Bougainville. Copelatus tulagicus Guignot, 1942, described from Tulaghi Island of the Solomons, is recorded from Guadalcanal and Santa Isabel for the first time. The widely distributed Australasian C. portior Guignot, 1956 is reported from the Solomon Islands (Guadalcanal and Ontong Java Atoll) for the first time. Two species from Guadalcanal remain unidentified since they are so far known only from a limited number of females., (Jiří Hájek, Helena Shaverdo, Lars Hendrich, Michael Balke.)

We provide the first report of the Nearctic diving beetle subfamily Coptotominae Van den Branden, 1885 for the Paleactic Region, based on † Coptotomus balticus sp. n. from Baltic amber. Coptotomus Say, 1830 is otherwise distributed with five extant species and one subspecies in the Nearctic Region. The new species is the smallest species of the genus and thus readily separated from the extant taxa.

DNA metabarcoding was utilized for a large-scale, multiyear assessment of biodiversity in Malaise trap collections from the Bavarian Forest National Park (Germany, Bavaria). Principal component analysis of read count-based biodiversities revealed clustering in concordance with whether collection sites were located inside or outside of the National Park. Jaccard distance matrices of the presences of barcode index numbers (BINs) at collection sites in the two survey years (2016 and 2018) were significantly correlated. Overall similar patterns in the presence of total arthropod BINs, as well as BINs belonging to four major arthropod orders across the study area, were observed in both survey years, and are also comparable with results of a previous study based on DNA barcoding of Sanger-sequenced specimens. A custom reference sequence library was assembled from publicly available data to screen for pest or invasive arthropods among the specimens or from the preservative ethanol. A single 98.6% match to the invasive bark beetle Ips duplicatus was detected in an ethanol sample. This species has not previously been detected in the National Park., (© 2020 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.)

Species of the ground beetle genus Pterostichus Bonelli, 1810 are some of the most common carabids in Europe. This publication provides a first comprehensive DNA barcode library for this genus and allied taxa including Abax Bonelli, 1810, Molops Bonelli, 1810, Poecilus Bonelli, 1810, and Stomis Clairville, 1806 for Germany and Central Europe in general. DNA barcodes were analyzed from 609 individuals that represent 51 species, including sequences from previous studies as well as more than 198 newly generated sequences. The results showed a 1:1 correspondence between BIN and traditionally recognized species for 44 species (86%), whereas two (4%) species were characterized by two BINs. Three BINs were found for one species (2%), while one BIN for two species was revealed for two species pairs (8%). Low interspecific distances with maximum pairwise K2P values below 2.2% were found for four species pairs. Haplotype sharing was found for two closely related species pairs: Pterostichus adstrictus Eschscholtz, 1823/ Pterostichus oblongopunctatus (Fabricius, 1787) and Pterostichus nigrita Paykull, 1790/ Pterostichus rhaeticus Heer, 1837. In contrast to this, high intraspecific sequence divergences with values above 2.2% were shown for three species ( Molops piceus (Panzer, 1793), Pterostichus panzeri (Panzer, 1805), Pterostichus strenuus (Panzer, 1793)). Summarizing the results, the present DNA barcode library does not only allow the identification of most of the analyzed species, but also provides valuable information for alpha-taxonomy as well as for ecological and evolutionary research. This library represents another step in building a comprehensive DNA barcode library of ground beetles as part of modern biodiversity research., (Michael J. Raupach, Karsten Hannig, Jérome Morinière, Lars Hendrich.)

Morphology and mitochondrial DNA sequence data are used to reassess the taxonomy of Australian diving beetles previously assigned to the genera Uvarus Guignot, 1939 and Gibbidessus Watts, 1978. Gibbidessus was described as a monotypic genus for Gibbidessus chipi Watts, 1978. The genus is significantly extended here. Based on molecular systematic evidence, Uvarus pictipes (Lea, 1899) is transferred to Gibbidessus . Gibbidessus chipi and Gibbidessus pictipes comb. nov. are redescribed, and six new species are described: Gibbiddessus atomus sp. nov. (SW Australia, Northcliffe area) [the smallest epigean diving beetle in Australia], G. davidi sp. nov. (SW Australia), G. drikdrikensis sp. nov. (Victoria), G. kangarooensis sp. nov. (SA Kangaroo Island), G. pederzanii sp. nov. (SW Australia, Nannup area), and G. rottnestensis sp. nov. (SW Australia). Species are delineated using characters such as male genital structure and beetle size, shape and colour pattern. Mitochondrial Cox1 data for 27 individuals, representing five species, were generated, and revealed clusters congruent with the morphological evidence. Gibbidessus occur in southern Australia, with the centre of diversification in the isolated peat- and wetlands of SW Australia. All species occur in very shallow water of seasonal, exposed or half-shaded wetlands and flooded meadows., (Lars Hendrich, Chris H.S. Watts, Michael Balke.)

We describe four new species of the diving beetle genus Liodessus Guignot from the high Andean regions of Peru: Liodessus alpinus sp. nov. from Junín, L. hauthi sp. nov. from Huánuco and Churubamba, L. rhigos sp. nov. from Junín, and L. thespesios sp. nov. from Cusco. We delineate the species using morphological structures and provide a 5' mitochondrial cytochrome c oxidase 1 database on the Barcode of Life Data System (BOLD). We also provide taxonomic notes on Liodessus acollensis Guignot, 1955 and L. andinus Guignot, 1957, described from the high Andes of Peru and Bolivia. These species occur at higher altitudes above 3,400 m and up to 4,900 m, and were collected in shallow, exposed peatland pools and puddles, mostly in steppes and high Andean Puna. The known distribution and habitat preferences of each species are outlined briefly.

Here we describe Limbodessus skalei sp. nov. from the island of Waigeo, off the coast of West Papua. It can be easily distinguished from the nearby New Guinea mainland species as well as the other members of the genus by its small size and testaceous elytra with conspicuous darker broad basal and subapical patches. Altogether four Limbodessus species are now known from the New Guinea region.

A new species of the genus Hydaticus Leach, 1817, subgenus Prodaticus Sharp, 1882 (Coleoptera: Dytiscidae) has been discovered in the mountains of Cerros del Sira, Peru. It is here described as Hydaticus (Prodaticus) hauthi sp. nov.. It is morphologically similar to the Peruvian H. panguana Megna, Balke, Apenborn Hendrich, 2019. The new species differs from H. panguana by its almost complete black dorsal surface and the shape of the median lobe. Diagnostic characters of both species, including illustrations of male genitalia and habitus, are presented, and a modified key for the 12 Neotropical species is provided.

The genus Copelatus in Australia is revised and nine species are recognised. One new species, Copelatus martinbaehri sp. nov. , is described from Papua New Guinea (Central Province) and Cape York Peninsula (Iron Range NP and Mt Tozer). Copelatus divisus Watts, 1978, syn. nov. , is considered a junior synonym of C. portior Guignot, 1956, described from New Guinea. Species delimitation is based on the morphological characters and Cox1 data. All species are (re)described, and their important species characters (median lobes, parameres, habitus and colour patterns) are illustrated. A key to all nine species is provided. The known distribution and habitat preferences of each species are outlined briefly. In Australia, all nine species are distributed in the northern half of the continent. Four species are also reported from New Guinea: in addition to C. martinbaehri sp. nov. , we record C. clarki Sharp, 1882 for the first time from southern New Guinea, and consider literature records of C. irregularis W.J. Macleay, 1871 and C. marginatus Sharp, 1882 from New Guinea as doubtful. Copelatus portior is widely distributed in Australasia, while C. tenebrosus is widely distributed in the Indomalayan and Australasian realms. All Australian Copelatus are confirmed to be lentic, found in a large variety of stagnant water, mainly in lowland areas up to 250 m., (Lars Hendrich, Helena Shaverdo, Jiří Hájek, Michael Balke.)

The aim of this study is to assess the species status of the Middle-European Thanasimus Latreille, 1806 species using mitochondrial CO1 sequence data. Molecular biological results clearly support the synonymy of T. pectoralis (Fuss, 1863) and T. rufipes (Brahm, 1797) with T. femoralis (Zetterstedt, 1828) as already proposed by Kolibáč (1992). Results of the present study indicate high genetic variation within T. formicarius (Linné, 1758) and emphasize the study of population dynamics of T. formicarius within Europe. Furthermore, preliminary screening of all available T. formicarius sequences on BOLD and Genbank (shorter than 500bp) indicates the presence of a "Continental" and a more "Atlantic" clade in T. formicarius. To support our hypothesis of a probably cryptic species among T. formicarius, more studies, with more specimens from different populations, especially from southern England, northern France and the northern part of the Iberian Peninsula, will be necessary.

This study summarizes results of a DNA barcoding campaign on German Diptera, involving analysis of 45,040 specimens. The resultant DNA barcode library includes records for 2,453 named species comprising a total of 5,200 barcode index numbers (BINs), including 2,700 COI haplotype clusters without species-level assignment, so called "dark taxa." Overall, 88 out of 117 families (75%) recorded from Germany were covered, representing more than 50% of the 9,544 known species of German Diptera. Until now, most of these families, especially the most diverse, have been taxonomically inaccessible. By contrast, within a few years this study provided an intermediate taxonomic system for half of the German Dipteran fauna, which will provide a useful foundation for subsequent detailed, integrative taxonomic studies. Using DNA extracts derived from bulk collections made by Malaise traps, we further demonstrate that species delineation using BINs and operational taxonomic units (OTUs) constitutes an effective method for biodiversity studies using DNA metabarcoding. As the reference libraries continue to grow, and gaps in the species catalogue are filled, BIN lists assembled by metabarcoding will provide greater taxonomic resolution. The present study has three main goals: (a) to provide a DNA barcode library for 5,200 BINs of Diptera; (b) to demonstrate, based on the example of bulk extractions from a Malaise trap experiment, that DNA barcode clusters, labelled with globally unique identifiers (such as OTUs and/or BINs), provide a pragmatic, accurate solution to the "taxonomic impediment"; and (c) to demonstrate that interim names based on BINs and OTUs obtained through metabarcoding provide an effective method for studies on species-rich groups that are usually neglected in biodiversity research projects because of their unresolved taxonomy., (© 2019 The Authors. Molecular Ecology Resources Published by John Wiley & Sons Ltd.)

We review the Peruvian Hydaticus Leach, 1817 (Coleoptera: Dytiscidae) and describe Hydaticus panguana sp. nov. from Huánuco Department. In the context of this work, we also provide new country records for several species: Hydaticus lateralis Laporte, 1835 (for Peru, Guyana, Venezuela, Suriname); H. xanthomelas (Brullé, 1837) (for Peru); H. subfasciatus Laporte, 1835 (for Colombia); H. fractivittis Guignot, 1951 (for Paraguay). Hydaticus riehli Wehncke, 1876 and H. verecundus Clark, 1864, described from "Cuba" and "South America", respectively, were probably mislabelled specimens, and do not belong to the Neotropical fauna. Diagnostic characters, including illustrations of male genitalia and habitus, are presented for seven of the 11 Neotropical species, and a modified key is provided. Altogether four species of Hydaticus are now known from Peru.

The beetle superfamily Dytiscoidea, placed within the suborder Adephaga, comprises six families. The phylogenetic relationships of these families, whose species are aquatic, remain highly contentious. In particular the monophyly of the geographically disjunct Aspidytidae (China and South Africa) remains unclear. Here we use a phylogenomic approach to demonstrate that Aspidytidae are indeed monophyletic, as we inferred this phylogenetic relationship from analyzing nucleotide sequence data filtered for compositional heterogeneity and from analyzing amino-acid sequence data. Our analyses suggest that Aspidytidae are the sister group of Amphizoidae, although the support for this relationship is not unequivocal. A sister group relationship of Hygrobiidae to a clade comprising Amphizoidae, Aspidytidae, and Dytiscidae is supported by analyses in which model assumptions are violated the least. In general, we find that both concatenation and the applied coalescent method are sensitive to the effect of among-species compositional heterogeneity. Four-cluster likelihood-mapping suggests that despite the substantial size of the dataset and the use of advanced analytical methods, statistical support is weak for the inferred phylogenetic placement of Hygrobiidae. These results indicate that other kinds of data (e.g. genomic meta-characters) are possibly required to resolve the above-specified persisting phylogenetic uncertainties. Our study illustrates various data-driven confounding effects in phylogenetic reconstructions and highlights the need for careful monitoring of model violations prior to phylogenomic analysis., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Megadytes (Bifurcitus) ducalis Sharp, 1882 is the largest diving beetle in the world and has been considered a candidate for the world's rarest insect (Jones 2010). It was described from "Brazil", is only known from the male holotype in the Natural History Museum (London), and typically thought to be extinct. Here we report the finding of 10 additional specimens, all collected at the end of the 19th century, which were discovered incidentally in different historical collections, including drawers with unsorted diving beetle accessions of the Muséum National d'Histoire Naturelle (Paris). These specimens, whilst old, reveal exact locality data for the first time, enabling focused field campaigns to attempt to rediscover this giant alive. Locality labels all indicate Santo Antônio da Barra (present name Condeúba), in the southern part of Bahia, Brazil, suggesting that the species may have a restricted distribution in wetter parts of the Brazilian savanna or cerrado. We also describe the female of M. ducalis for the first time and present new records of the putatively closely related species Megadytes magnus Trémouilles Bachmann, 1980 and M. lherminieri (Guérin-Méneville, 1829), the latter being recorded for the first time from Ecuador. These three morphologically similar species together form the subgenus Bifurcitus Brinck, 1945 and we provide photographs of their habitus, median lobes and other morphological details.

We provide the first report of the subfamily Laccophilinae Gistel, 1848 from Baltic amber, based on a female specimen collected in Russia, Kaliningrad Region, Yantarnii (Jantarny) mine. This specimen represents a new species and could be assigned to the extant genus Japanolaccophilus Satô, 1972. To date this genus was monotypic with one species in Japan. The new species is here described as †J. beatificus sp. n. and compared with the extant Japanolaccophilus niponensis (Kamiya, 1939). We also provide a modified key to the Laccophilinae genera of the World, as we found minor errors or ambiguities in recent keys.