Stoneflies (Insecta: Plecoptera) are a widespread group of freshwater insects known for their ecological significance and sensitivity to environmental change. This diverse order encompasses over 4,000 species across 17 families, with the number of described species predicted to increase substantially over the coming years. This review surveys the past and present landscape of stonefly systematics, emphasizing recent advancements in our understanding of the phylogenetic relationships within this group to the ordinal, subordinal, and family level. We highlight the need for expanded biodiversity surveys, particularly in underexplored regions such as high-elevation ecosystems, the Southern Hemisphere, and the Arctic, and identify the key challenges impeding the advancement of systematic research, in particular the decline in taxonomic expertise. Looking forward, we outline a vision for the future of stonefly systematic research, advocating for increased inclusivity, collaborative research efforts, and the integration of advanced molecular methodologies.

The phylogeny of 'broad-nosed weevils' is explored with a data set of mitochondrial genomes of 130 species, representing 32 tribes. Phylogenetic analyses recovered a subdivision of Entiminae Schoenherr, 1823 into a 'northern clade' of mostly Palaearctic, Indomalayan, and African taxa and a 'southern clade' of Australian, Oceanian, and South American groups. Biogeographical reconstructions infer the origin of Entiminae in the Late Cretaceous in the Holarctic and a range expansion of the 'southern clade' from North America to South America. A group of genera with a 'leptopiine' type of rostrum are polyphyletic and subdivided based on zoogeographical regions: the Palaearctic and Nearctic genera remain in Byrsopagini Lacordaire, 1863; the Neotropical genera are placed in Strangaliodini Lacordaire, 1863; and the Indoaustralian genera are placed in Pantopoeini Lacordaire, 1863 (stat. nov.), which are given priority over Prypnini Lacordaire, 1863; the following names are junior synonyms of Pantopoeini: Elytrurini Marshall, 1956, syn. nov., Eupholini G & uuml;nther, 1943, syn. nov, Leptopiini Oke, 1951, syn. nov., and Polycatini Marshall, 1956, syn. nov. Isopterina Morimoto & Kojima, 2001 is excluded from Celeuthetini Lacordaire, 1863 and promoted as tribe Isopterini (stat. nov.). The Sitoninae Gistel, 1848 (stat. nov.) are elevated to subfamily rank. Rhyncholobus Gahan, 1900 is transferred to Episomini Lacordaire, 1863. The Celeuthetini are sister group of Pachyrhynchini Schoenherr, 1826.

Name-bearing type specimens have a fundamental role in characterizing biodiversity, as these objects represent the physical link between a scientific name and the biological organism. Type specimens are usually deposited in natural history collections, which provide key infrastructure for research on essential biological structures and processes, while preserving records of biodiversity for future generations. Modern systematics increasingly depends on genetic and genomic data to differentiate and characterize species. While the results of genome sequencing are often connected to a physical voucher specimen, they are rarely derived from the ultimate taxonomic reference for a species, that is, the name-bearing type specimens. This is a known but underappreciated problem for ensuring the replicability of findings, especially those that affect the interpretation of biodiversity distributions and phylogenetic relationships. Destructive sampling of museum specimens, particularly of type material, often carries a high risk of sequencing failure, and thus the cost of damage to the specimen may outweigh the resulting benefit. Both taxonomic work and genome sequencing require specialist skills, and there are often communication gaps between the respective experts. A new, harmonized approach, maximizing information extraction while minimizing risk to type specimens, is a critical step forward toward linking disciplines across biodiversity research and promoting a better taxonomic and systematic understanding of eukaryotic diversity. The genetic makeup of a type specimen is a fundamental part of its biological information, which can and should be made freely and digitally available through type genomics. Here, we describe guidelines for the use of nomenclatural types in genome sequencing approaches, considering different kinds of types in different stages of preservation and different data types.

Flea beetles of the genus Psylliodes have evolved specialized interactions with plant species belonging to several distantly related families, mainly Brassicaceae, Solanaceae, and Fagaceae. This diverse host use indicates that Psylliodes flea beetles are able to cope with different chemical defense metabolites, including glucosinolates, the characteristic defense metabolites of Brassicaceae. Here we investigated the evolution of host use and the emergence of a glucosinolate-specific detoxification mechanism in Psylliodes flea beetles. In phylogenetic analyses, Psylliodes species clustered into four major clades, three of which contained mainly species specialized on either Brassicaceae, Solanaceae, or Fagaceae. Most members of the fourth clade have broader host use, including Brassicaceae and Poaceae as major host plant families. Ancestral state reconstructions suggest that Psylliodes flea beetles were initially associated with Brassicaceae and then either shifted to Solanaceae or Fagaceae, or expanded their host repertoire to Poaceae. Despite a putative ancestral association with Brassicaceae, we found evidence that the evolution of glucosinolate-specific detoxification enzymes coincides with the radiation of Psylliodes on Brassicaceae, suggesting that these are not required for using Brassicaceae as hosts but could improve the efficiency of host use by specialized Psylliodes species.

Ceutorhynchinae Gistel are a diverse weevil subfamily of almost worldwide distribution and considerable economic importance. Nevertheless, the classification of Ceutorhynchinae and their phylogenetic relationships are not yet fully resolved. Here, we sequenced the mitogenomes of 54 ceutorhynchine species. Phylogenetic analyses by maximum likelihood and Bayesian inference were performed on a dataset of 13 protein-coding and two ribosomal genes. All analyses recovered three well supported clades A-C. A principal component analysis shows that codon usage differs considerably between these clades, indicating a compositional asymmetry in ceutorhynchine mitogenomes. This increased the challenge of resolving the early relationships among the three clades. The resolution of the later diversification was more robust, and the resulting topologies were largely compatible with each other and with the current taxonomic classification. Exceptions are the genera Micrelus Thomson, which is transferred from the tribe Ceutorhynchini to Egriini Pajni and Kohli (new position) and Amalus Schoenherr, which is transferred to Phytobiini Gistel (new position). Amalini Wagner 1936 is a junior synonym of Phytobiini Gistel 1848 (syn. n.). Coeliodini Lacordaire (new status), a tribe previously regarded as junior synonym of Ceutorhynchini, is re-established. Our analyses also clarified the difficult assignments of taxa to the tribes Scleropterini Schultze and Phytobiini. All taxa with the ability to jump as adult beetles belong to clade B, which comprises the tribes Cnemogonini Colonnelli, Hypurini Schultze, Mecysmoderini Wagner and Phytobiini. With dense taxon sampling and appropriate analytical methods, mitogenome data provide a phylogeny well suited to improve the traditional classification of this neglected and species-rich taxon. Fifty-four newly sequenced mitochondrial genomes of Ceutorhynchinae weevils First comprehensive molecular dataset to infer phylogenetic relationships of Ceutorhynchinae Inference of a compositional asymmetry in ceutorhynchine mitogenomes image

The geologically‐complex Indo–Australian–Melanesian archipelago (IAMA) hosts extraordinarily high levels of species richness and endemism and has long served as a natural laboratory for studying biogeography and evolution. Nonetheless, its geological history and the provenance and evolution of its biodiversity remain poorly understood. Here, we provide a geological scenario for the IAMA informed by a time‐calibrated molecular phylogeny of 1006 species of Trigonopterus weevils – an exceptionally diverse radiation of regionally‐endemic flightless beetles. Moreover, we performed a statistical biogeographic analysis and examined timing and patterns in the accumulation of lineages residing in a priori‐defined geographic units comprising the IAMA. We estimate that Trigonopterus originated in Australia during the early Paleogene. Subsequent rapid diversification in the area of the present‐day Papuan Peninsula suggests the presence of proto‐Papuan islands by the middle Eocene; the New Guinea North Coast Ranges were colonized in the late Eocene, followed by the New Guinea Highlands and the Bird's Head Peninsula. We inferred the presence of terrestrial habitat in the North Moluccas and Sulawesi in the late Oligocene and the subsequent rapid colonization of Sundaland and the Lesser Sunda Islands. New Caledonia and Samoa were colonized from the Papuan Peninsula, and their faunas also diverged in the late Oligocene. These biota‐informed time estimates are compatible with geological data from the region and shed new light on IAMA paleogeography, even where geological evidence has been lost to erosion. Beetle evolution thus appears to have closely tracked the geological evolution of the IAMA, revealing a uniquely well‐resolved view of regional biogeography.

Flea beetles (Alticini) represent one of the most diverse groups within the family Chrysomelidae and are associated with more than 100 different plant families. Conspicuously, only 10 genera account for about a quarter of flea beetle diversity, whereas about 380 genera each comprise less than 10 species, indicating different rates of diversification within the Alticini. Here, we reconstructed the phylogenetic relationships of 608 species in 101 Alticini genera using mitogenomes and cytochrome oxidase I, and applied several frameworks of clade-specific diversification rate analyses. Increased diversification rates were consistently detected in the cosmopolitan genera Altica Goffroy, Longitarsus Berthold, and Phyllotreta Chevrolat, and in neotropical taxa of the subtribe Oedionychina. In addition, we tested whether the evolution of specialized interactions with plants of the order Brassicales influenced the diversification of Phyllotreta and Psylliodes Berthold flea beetles. Specialization on Brassicales was only associated with increased diversification rates in Phyllotreta but not in Psylliodes. Our results indicate that host associations per se do not explain different diversification rates and lay the groundwork for investigating the evolutionary drivers of rapid radiations in Alticini.

Abstract Flea beetles (Alticini) represent one of the most diverse groups within the family Chrysomelidae and are associated with more than 100 different plant families. Conspicuously, only 10 genera account for about a quarter of flea beetle diversity, whereas about 380 genera each comprise less than 10 species, indicating different rates of diversification within the Alticini. Here, we reconstructed the phylogenetic relationships of 608 species in 101 Alticini genera using mitogenomes and cytochrome oxidase I, and applied several frameworks of clade-specific diversification rate analyses. Increased diversification rates were consistently detected in the cosmopolitan genera Altica Goffroy, Longitarsus Berthold, and Phyllotreta Chevrolat, and in neotropical taxa of the subtribe Oedionychina. In addition, we tested whether the evolution of specialized interactions with plants of the order Brassicales influenced the diversification of Phyllotreta and Psylliodes Berthold flea beetles. Specialization on Brassicales was only associated with increased diversification rates in Phyllotreta but not in Psylliodes. Our results indicate that host associations per se do not explain different diversification rates and lay the groundwork for investigating the evolutionary drivers of rapid radiations in Alticini.

Extant members of the ancient insect order of stoneflies exhibit a disjunct, antitropical distribution, with one major lineage exclusively occurring in the Southern Hemisphere and the other, with few exceptions, on the Northern continents. Here, we address the biogeographic distribution and phylogenetic relationships of stoneflies using a phylogenetic workflow that combines both transcriptomic and Sanger sequence datasets with heterogeneous taxon coverage. We used a dataset comprising 2997 genes derived from the transcriptomes of 30 species and Sanger sequences of seven genes for 498 species. The backbone phylogeny was mainly inferred from the transcriptomic data, whereas the Sanger nucleotide sequence data provided high species density for divergence time estimation and diversification analyses. Our results show that the biogeographic pattern we observe today is primarily more likely shaped by long‐distance over‐land dispersal than by vicariance. We inferred that the ancestors of extant stoneflies originated in the Northern Hemisphere approximately 265 Ma and were presumably restricted to this area due to climatic and geographic boundaries. Our analyses suggest that with the break‐up of Pangaea around 200 Ma and the associated climatic and geographical changes, two groups of stoneflies, the Anarctoperlaria and the Notonemouridae, dispersed to Gondwana and subsequently went extinct on the northern continents. Both groups likely dispersed across Gondwana before its break‐up into the modern continents. At least one member of another group of ‘northern’ stoneflies, the Acroneuriinae, seems to have migrated from North America to South America around 67 Ma. We found four major net diversification rate shifts, indicating rapid radiation patterns that hampered a robust phylogenetic placement of these stonefly groups. Our study provides the first conclusive evolutionary explanation for the unique distribution pattern of stoneflies.

Dragonflies and damselflies are among the earliest flying insects with extant representatives. However, unraveling details of their long evolutionary history, such as egg laying (oviposition) strategies, is impeded by unresolved phylogenetic relationships, particularly in damselflies. Here we present a transcriptome-based phylogenetic reconstruction of Odonata, analyzing 2,980 protein-coding genes in 105 species representing nearly all the order’s families. All damselfly and most dragonfly families are recovered as monophyletic. Our data suggest a sister relationship between dragonfly families of Gomphidae and Petaluridae. According to our divergence time estimates, both crown-Zygoptera and -Anisoptera arose during the late Triassic. Egg-laying with a reduced ovipositor apparently evolved in dragonflies during the late Jurassic/early Cretaceous. Lastly, we also test the impact of fossil choice and placement, particularly, of the extinct fossil species, †Triassolestodes asiaticus, and †Proterogomphus renateae on divergence time estimates. We find placement of †Proterogomphus renateae to be much more impactful than †Triassolestodes asiaticus.

The first dated phylogeny of the weevil subfamily Cryptorhynchinae is presented within a framework of Curculionoidea. The inferred pattern and timing of weevil family relationships are generally congruent with previous studies, but our data are the first to suggest a highly supported sister-group relationship between Attelabidae and Belidae. Our biogeographical inferences suggest that Cryptorhynchinae s.s. originated in the Late Cretaceous (c. 86 Ma) in South America. Within the 'Acalles group' and the 'Cryptorhynchus group', several independent dispersal events to the Western Palaearctic via the Nearctic occurred in the Late Cretaceous and Early Paleogene. A second southern route via Antarctica may have facilitated the colonization of Australia in the Late Cretaceous (c. 82 Ma), where a diverse Indo-Australian clade probably emerged c. 73 Ma. In the Early Eocene (c. 50-55 Ma), several clades independently dispersed from Australia to proto-New Guinea, i.e. the tribe Arachnopodini s.l., the 'Rhynchodes group' and the genus Trigonopterus. New Zealand was first colonized in the Late Palaeocene (c. 60 Ma). Divergence time estimations and biogeographical reconstructions indicate that the colonization of New Guinea is older than expected from current geological reconstructions of the region.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Wallace's Line, located in the heart of the Indo-Australian archipelago, has historically been hypothesized to strongly inhibit dispersal. Taxa crossing this barrier are confronted with different biota of Asian or Australian origin, respectively, but the extent to which these conditions have affected the evolution of the colonizing lineages remains largely unknown. We examined the potential correlations of body size, lifestyle and biogeographical distribution in the weevil genus Trigonopterus. These beetles are highly diverse both on foliage and in litter east of Wallace's Line but occur exclusively in leaf litter in the west. Based on a comprehensive, dated phylogeny of 303 species, we inferred nine crossing events of Wallace's Line, all from east to west. Five previously foliage-dwelling lineages changed their lifestyle to leaf litter habitats after crossing this barrier. Our results indicate that dispersal is not more likely in edaphic lineages, but rather that abiotic and/or biotic factors may be responsible for the exclusive leaf litter habitat of Trigonopterus in Sundaland. This includes differences in climate, and the different predatory faunas of Australia-New Guinea, Wallacea and Sundaland. A mimicry complex in New Guinea with Trigonopterus species as presumable model may be of relevance in this context.

Summary Dragonflies and damselflies, representing the insect order Odonata, are among the earliest flying insects with living (extant) representatives. However, unravelling details of their long evolutionary history, such as egg laying (oviposition) strategies, is impeded by unresolved phylogenetic relationships, an issue particularly prevalent in damselfly families and fossil lineages. Here we present the first transcriptome-based phylogenetic reconstruction of Odonata, analyzing 2,980 protein-coding genes in 105 species representing nearly all of the order’s families (except Austropetaliidae and Neopetaliidae). All damselfly families and most dragonfly families are recovered as monophyletic groups. Our Molecular clock estimates suggest that crown-Zygoptera (damselflies) and -Anisoptera (dragonflies) both arose during the late Triassic. Several of the observed long inner branches in our topology are indicative of the extinction of once flourishing lineages. We also find that exophytic egg laying behaviour with a reduced ovipositor evolved in certain dragonflies during the late Jurassic / early Cretaceous. Lastly, we find that certain fossils have an unexpected deterring impact in divergence dating analysis.

The order Coleoptera (beetles) is arguably the most speciose group of animals, but the evolutionary history of beetles, including the impacts of plant feeding (herbivory) on beetle diversification, remain poorly understood. We inferred the phylogeny of beetles using 4,818 genes for 146 species, estimated timing and rates of beetle diversification using 89 genes for 521 species representing all major lineages and traced the evolution of beetle genes enabling symbiont-independent digestion of lignocellulose using 154 genomes or transcriptomes. Phylogenomic analyses of these uniquely comprehensive datasets resolved previously controversial beetle relationships, dated the origin of Coleoptera to the Carboniferous, and supported the codiversification of beetles and angiosperms. Moreover, plant cell wall-degrading enzymes (PCWDEs) obtained from bacteria and fungi via horizontal gene transfers may have been key to the Mesozoic diversification of herbivorous beetles-remarkably, both major independent origins of specialized herbivory in beetles coincide with the first appearances of an arsenal of PCWDEs encoded in their genomes. Furthermore, corresponding (Jurassic) diversification rate increases suggest that these novel genes triggered adaptive radiations that resulted in nearly half of all living beetle species. We propose that PCWDEs enabled efficient digestion of plant tissues, including lignocellulose in cell walls, facilitating the evolution of uniquely specialized plant-feeding habits, such as leaf mining and stem and wood boring. Beetle diversity thus appears to have resulted from multiple factors, including low extinction rates over a long evolutionary history, codiversification with angiosperms, and adaptive radiations of specialized herbivorous beetles following convergent horizontal transfers of microbial genes encoding PCWDEs.

Phasmatodea comprises over 3,000 extant species and stands out as one of the last remaining insect orders for which a robust, higher-level phylogenetic hypothesis is lacking. New research suggests that the extant diversity is the result of a surprisingly recent and rapid radiation that has been difficult to resolve with standard Sanger sequence data. In order to resolve the early branching events of stick and leaf insects, we analyzed transcriptomes from 61 species, including 38 Phasmatodea species comprising all major clades and 23 outgroup taxa, including all other Polyneoptera orders. Using a custom-made ortholog set based on reference genomes from four species, we identified on average 2,274 orthologous genes in the sequenced transcriptomes. We generated various sub-alignments and performed maximum-likelihood analyses on several representative datasets to evaluate the effect of missing data and matrix composition on our phylogenetic estimates. Based on our new data, we are able to reliably resolve the deeper nodes between the principal lineages of extant Phasmatodea. Among Euphasmatodea, we provide strong evidence for a basal dichotomy of Aschiphasmatodea and all remaining euphasmatodeans, the Neophasmatodea. Within the latter clade, we recovered a previously unrecognized major New World and Old World lineage, for which we introduce the new names Oriophasmata tax. nov. ("Eastern phasmids") and Occidophasmata tax. nov. ("Western phasmids"). Occidophasmata comprise Diapheromerinae, Pseudophasmatinae, and Agathemera, whereas all remaining lineages form the Oriophasmata, including Heteropterygidae, Phylliinae, Bacillus, Lonchodidae (Necrosciinae + Lonchodinae), Clitumninae, Cladomorphinae, and Lanceocercata. We furthermore performed a divergence time analysis and reconstructed the historical biogeography for stick and leaf insects. Phasmatodea either originated in Southeast Asia or in the New World. Our results suggest that the extant distribution of Phasmatodea is largely the result of dispersal events in a recently and rapidly diversified insect lineage rather than the result of vicariant processes.

Polyneoptera represents one of the major lineages of winged insects, comprising around 40,000 extant species in 10 traditional orders, including grasshoppers, roaches, and stoneflies. Many important aspects of polyneopteran evolution, such as their phylogenetic relationships, changes in their external appearance, their habitat preferences, and social behavior, are unresolved and are a major enigma in entomology. These ambiguities also have direct consequences for our understanding of the evolution of winged insects in general; for example, with respect to the ancestral habitats of adults and juveniles. We addressed these issues with a large-scale phylogenomic analysis and used the reconstructed phylogenetic relationships to trace the evolution of 112 characters associated with the external appearance and the lifestyle of winged insects. Our inferences suggest that the last common ancestors of Polyneoptera and of the winged insects were terrestrial throughout their lives, implying that wings did not evolve in an aquatic environment. The appearance of the first polyneopteran insect was mainly characterized by ancestral traits such as long segmented abdominal appendages and biting mouthparts held below the head capsule. This ancestor lived in association with the ground, which led to various specializations including hardened forewings and unique tarsal attachment structures. However, within Polyneoptera, several groups switched separately to a life on plants. In contrast to a previous hypothesis, we found that social behavior was not part of the polyneopteran ground plan. In other traits, such as the biting mouthparts, Polyneoptera shows a high degree of evolutionary conservatism unique among the major lineages of winged insects.

The 2016 International Weevil Meeting was held immediately after the International Congress of Entomology (ICE). It built on the topics and content of the 2016 ICE weevil symposium Phylogeny and Evolution of Weevils (Coleoptera: Curculionoidea): A Symposium in Honor of Dr. Guillermo "Willy Kuschel. Beyond catalyzing research and collaboration, the meeting was intended to serve as a forum for identifying priorities and goals for those who study weevils. The meeting consisted of 46 invited and contributed lectures, discussion sessions and introductory remarks presented by 23 speakers along with eight contributed research posters. These were organized into three convened sessions, each lasting one day: (1) weevil morphology; (2) weevil fossils, biogeography and host/habitat associations; and (3) molecular phylogenetics and classification of weevils. Some of the topics covered included the 1K Weevils Project, major morphological character systems of adult and larval weevils, weevil morphological terminology, prospects for future morphological character discovery, phylogenetic analysis of morphological character data, the current status of weevil molecular phylogenetics and evolution, resources available for phylogenetic and comparative genomic studies of weevils, the weevil fossil record, weevil biogeography and evolution, weevil host plants, evolutionary development of the weevil rostrum, resources available for weevil identification and the current status of and challenges in weevil classification.

Using molecular phylogenetic data and methods we inferred divergence times and diversification patterns for the weevil subfamily Ceutorhynchinae in the context of host-plant associations and global climate over evolutionary time. We detected four major diversification shifts that correlate with both host shifts and major climate events. Ceutorhynchinae experienced an increase in diversification rate at ∼53 Ma, during the Early Eocene Climate Optimum, coincident with a host shift to Lamiaceae. A second major diversification phase occurred at the end of the Eocene (∼34 Ma). This contrasts with the overall deterioration in climate equability at the Eocene-Oligocene boundary, but tracks the diversification of important host plant clades in temperate (higher) latitudes, leading to increased diversification rates in the weevil clades infesting temperate hosts. A third major phase of diversification is correlated with the rising temperatures of the Late Oligocene Warming Event (∼26.5 Ma); diversification rates then declined shortly after the Middle Miocene Climate Transition (∼14.9 Ma). Our results indicate that biotic and abiotic factors together explain the evolution of Ceutorhynchinae better than each of these drivers viewed in isolation.

The Palaearctic butterfly genus Pseudophilotes Beuret, 1958 (Lycaenidae: Polyommatinae), that today occurs in North Africa and in Eurasia, includes ten described species with various distribution ranges, including endemics such as the Sardinian P. barbagiae. Phylogenetic relationships among these species are largely unresolved. In the present study, we analysed 158 specimens, representing seven species out of ten described in the genus, from widely distributed sites throughout the western Palaearctic region, using nuclear markers (28S rRNA, wingless, Internal Transcribed Spacer 2 and Elongation Factor 1α) and the barcoding region of the mitochondrial cytochrome c oxidase subunit 1 gene to investigate if the current taxonomic entities match the phylogenetic pattern. Further, we attempt to infer the geographic origin of the genus Pseudophilotes and estimate the timing of its radiations, including the split of the Sardinian endemic P. barbagiae.