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South Pacific archipelagos are central in the biogeographic debate on the relative importance of vicariance and dispersal in shaping the distribution of species. However, each taxonomic group was subject to different processes and histories, and here, we reveal the historical biogeography of the diverse Eumolpinae leaf beetles, widely distributed in the region. Extensive taxon sampling focusing on South Pacific Eumolpinae was used to infer the first molecular phylogeny of the group using three single‐copy protein‐coding nuclear and two mitochondrial markers. Upon assessing the clade of interest for lineage‐specific variation in substitution rates, the age of the most recent common ancestors was estimated using out‐group calibration and multi‐gamma site models (MGSMs). Biogeographic analyses used standard event‐based inferences also incorporating phylogenetic uncertainty. Zealandian Eumolpinae are monophyletic and appear to have split from their global relatives in the transition from the Cretaceous to the Paleogene. Variation in the rates of molecular evolution affected the in‐group stem branch, with a significant drop in the substitution rate, and the MGSM correction recovered the crown age of Zealandian Eumolpinae during the Late Eocene–Oligocene transition. Biogeographic inference resolved the origin of the radiation in New Caledonia, favouring a null model without island age constraints, and repeated dispersal events to the other islands, including three independent but synchronous colonisations of New Zealand during the Miocene. New Caledonia, with a highly diverse Eumolpinae fauna of uncertain origin, acted as a hub and pump of biodiversity of these beetles in the entire South Pacific region, sending migrants to other islands through long‐distance dispersal with lineages establishing when land became available. [ABSTRACT FROM AUTHOR]

Forest soil and leaf litter support diverse arthropod mesofauna for which diversity dynamics is challenging to study due to the high number of species and specimens, small body size and limited taxonomic knowledge.Immature stages (larvae) are even harder to identify than adults, as their morphology is largely unknown. Therefore, larvae are often ignored, even though they may form a substantial proportion of specimens collected, are less mobile than adults and their exclusion may provide an incomplete diversity profile.Here, we use Oxford Nanopore DNA barcoding to investigate whether the inclusion of larvae provides a more complete taxonomic, phylogenetic and functional diversity profiles in leaf litter beetles (Coleoptera) from a subtropical forest in Taiwan.Our results indicate that larvae represent up to 38% of beetle specimens per sample, but most of them belong to 2–3 common species. Larvae of most beetle species are rarely collected repeatedly or in multiple specimens, possibly due to special habitat requirements or high seasonality.Taxonomic, phylogenetic and incidence‐based functional diversity measures were not affected by the exclusion of larvae in the Staphylinidae dataset but were strongly biased in all‐beetle dataset, especially when only common or abundant species were considered. Taxonomic beta diversity was not affected by the omission of larvae.Our results indicate that immature stages may be omitted in ecological studies of arthropods in case both adults and larvae co‐occur in the same habitat, and the sites are sampled repeatedly. Caution is needed (1) in groups in which larvae and adults do not inhabit the same environment or strongly differ in biology, (2) when rare species are omitted or (3) when functional diversity is calculated from abundance data. [ABSTRACT FROM AUTHOR]

Aim: Although Antarctica hosted a diverse fauna and flora in the past, its modern climate is too extreme for many lineages: their recent extinction makes it difficult to include the continent in historical biogeographical analyses. We use southern temperate stream‐inhabiting beetles as a model to explore whether Antarctica may be included in historical biogeographic reconstructions in a group absent from Antarctica today, and to test its role in shaping the current distribution of stream‐inhabiting insects. Taxon: Coleoptera, Elmidae. Location: Southern Hemisphere temperate regions and Antarctica. Methods: We included Antarctica in historical biogeographic analyses indirectly, as a component of distance matrices specifying the relative positions of continents, or by specifying Antarctica as a stepping‐stone between remaining continents (in LEMAD). We used a newly constructed dated phylogeny of Elmidae to test the performance of these constrained analyses under different parameter settings and geographical scenarios. Results: Antarctica can be implemented into historical biogeographic analyses via indirect constraints to produce biologically relevant reconstructions when long‐distance dispersal events are highly penalized, the maximum number of areas per species is low, and expected extinction rates are high (in LEMAD). Unconstrained models, including those without Antarctica, result in simpler scenarios with fewer biogeographic events and better fit to data. The origin of austral clades of Elmidae post‐date the separation of Gondwanan landmasses. Main Conclusions: Antarctica can be included in historical biogeographic reconstructions under a priori assumptions that (1) it was part of the ancient biogeography of the clade, (2) the taxon has limited dispersal ability, making long‐distance dispersal highly unlikely and (3) maximum range size is limited. These assumptions may be biologically justified for many animal groups. Over‐water dispersal has been crucial in shaping the modern distribution of austral stream‐inhabiting beetles, likely facilitated by ocean currents and dispersal through Antarctica until the Oligocene. [ABSTRACT FROM AUTHOR]

Army ants provide nourishment to a large variety of animals. This includes birds that feed on animals flushed out by army ant raids, symbiotic arthropods that consume the ants' prey or their brood, and other arthropods that scavenge on army ant refuse deposits. The latter have not received much attention, and the few published studies lack detailed species identifications. Here we provide a first systematic inventory of the beetle fauna associated with refuse deposits of Eciton army ants, with a focus on Eciton burchellii. We collected 8364 adult beetles, 511 larvae, and 24 eggs from 34 deposits at La Selva Biological Station, Costa Rica. We used a combination of DNA barcoding and morphology to identify a subset of 436 specimens to species level. The samples included several new species, and we here formally describe two water scavenger beetles (Hydrophilidae). Refuse deposits harbored a diverse beetle fauna. The identified subset consisted of 91 beetle species from 12 families, with rove beetles being the most abundant and diverse visitors. Of the 85 species found with E. burchellii, 50 species were collected from only one or two refuse deposits. Conversely, seven species were found in 10 or more refuse deposits, indicating a certain level of habitat specialization. We matched adults and immatures for 22 beetle species via DNA barcodes, demonstrating that army ant middens also serve as a beetle nursery. The present survey highlights the significant ecological function of army ants as promoters of biodiversity and their status as keystone species in tropical rainforests. [ABSTRACT FROM AUTHOR]

Systematic bias is one of the major phylogenetic issues arising over the last two decades. Using methods designed to reduce compositional and rate heterogeneity, hence systematic bias, Cai and co‐workers (2022) (= CEA22) reanalyzed the DNA sequence dataset for Coleoptera of Zhang et al. (2018) (= ZEA). CEA22 suggest that their phylogenetic results and major evolutionary hypotheses about the Coleoptera should be favoured over other recently published studies. Here, we discuss the methodology of CEA22 with particular attention to how their perfunctory reanalysis of ZEA obfuscates rather than illuminates beetle phylogeny. Similar to published rebuttals of an earlier study of theirs, we specifically find that many of their claims are misleading, unsupported, or false. Critically, CEA22 fail to establish the stated premise for their reanalysis. They fail to demonstrate how composition or rate heterogeneity supposedly impacted the phylogeny estimate of ZEA, let alone the results of other recent studies. Moreover, despite their claim of comprehensive sampling of Coleoptera, their dataset is neither the most diverse with respect to species and higher taxa included, nor anywhere near the largest in terms of sequence data and sampled loci. Although CEA22 does contribute additional fossils for calibration, those seeking the best available estimate for Coleoptera phylogeny and evolution based on molecular data are advised to look elsewhere. [ABSTRACT FROM AUTHOR]

Sphaeriusidae (Coleoptera: Myxophaga) is a group of shiny, blackish and hemispherical riparian beetles, known for their miniaturized bodies. They are worldwide in distribution, but very limited information is available about taxonomic and morphological diversity, and natural and evolutionary history. The aim of this study is to help fill in these gaps. We examined the external morphology of modern representatives using scanning electron microscopy (SEM), and reconstructed the phylogeny of the family using five DNA markers (cytochrome oxidase I, 18S rRNA, 28S rRNA, CAD and wingless). Our results suggest a larger morphological diversity than previously expected, corresponding to the deep genetic divergences of principal lineages. We also examined two inclusions in 99‐million‐year‐old Burmese amber. The integration of all evidence allows us to recognize three genera: the extinct genus †Burmasporum Kirejtshuk, the newly defined genus Bezesporumgen.nov. preserved in Burmese amber (B. burmiticumsp.nov.) and present in the modern fauna of Southeast Asia, and the genus Sphaerius Waltl with a world‐wide distribution. Sphaerius species are morphologically highly uniform, with the exception of species from Australia and South Africa, which share some characteristics with Bezesporumgen.nov. despite being resolved as deeply nested lineages of Sphaerius by DNA data. The presence of Bezesporumgen.nov. in Burmese amber and in recent fauna indicates that Sphaeriusidae largely maintained their specific morphology and specialized riparian lifestyle for at least 100 million years. Therefore, they can be considered an exceptionally conserved group, with a minimum of evolutionary changes over a long period. Our study also demonstrates that the species numbers and fine‐scale morphological diversity of Sphaeriusidae are larger than expected in both the past and present‐day faunas. Both were apparently underestimated due to the minute body size and cryptic habits of these beetles. [ABSTRACT FROM AUTHOR]

Moss‐inhabiting flea beetles form a very diverse and understudied ecological group of leaf beetles (Coleoptera: Chrysomelidae) characterized by cryptic lifestyle, loss of flight ability and feeding on mosses as both adults and larvae. We present the first DNA‐based study of the phylogenetic position of moss‐inhabiting flea beetle genera Ivalia Jacoby and Cangshanaltica Konstantinov et al., based on sequences of two mitochondrial and three nuclear genes. We confirm that both genera are members of the monophyletic Chabria group, along with Chabria Jacoby, Parathrylea Duvivier, Chabriosoma Chen and Sutrea Baly. Moss‐inhabiting species form at least three independent lineages within the Chabria group, indicating multiple parallel origin of the association with mosses within the clade. We reveal the monophyly of Cangshanaltica and confirm its separate generic status from Ivalia. Ivalia is revealed as polyphyletic, consisting of at least two unrelated moss‐inhabiting lineages. In contrast, the externally similar moss‐ and leaf‐litter inhabiting genera Mniophila Stephens, Adamastoraltica Biondi et al. and Clavicornaltica Scherer are not closely related to the Chabria group. Our study specifically focused on the moss‐inhabiting flea beetles of Taiwan. We reveal that the Taiwanese fauna is a result of four independent colonizations of the island: one from China (Cangshanaltica) and three from the Philippines (three lineages morphologically assigned to Ivalia). Two of these lineages (Cangshanaltica and the core Ivalia) radiated in Taiwan and gave rise to the majority of modern Taiwanese species. The evolutionary history of Cangshanaltica and its diversification in China are also discussed. [ABSTRACT FROM AUTHOR]

Megasternini is the largest group of terrestrial water scavenger beetles (Coleoptera: Hydrophilidae) represented by ca. 600 described species distributed worldwide. The highest species diversity is known from tropical areas of all continents. In this study, we used sequences of eight gene regions (five nuclear and three mitochondrial) to investigate the phylogenetic relationships and historical biogeography of this group, implementing maximum likelihood (ML) and Bayesian topology inference, Bayesian divergence dating, ML‐based ancestral area estimation and Bayesian diversification analyses. Topology analyses reveal two main lineages of Megasternini characterized by the morphology of male genitalia and surrounding sclerites; these lineages are defined here as subtribes Megasternina Mulsant and Oosternina new subtribe. We identify 12 principal clades of Megasternini, three in Oosternina and nine in Megasternina. These clades group the taxa largely by their geographic distribution rather than morphology, indicating a parallel evolution of morphological characters. Genera Cercyon Leach, Oosternum Sharp, Cetiocyon Hansen, Australocyon Hansen and Pelosoma Mulsant were not recovered as monophyletic. Species of Cercyon, the most diverse genus in the tribe, are found in all principal clades in both subtribes. These results suggest a need for the reorganization of generic concepts in the tribe. The historical biogeography analysis reveals a series of parallel intercontinental dispersal events, including the colonization of South America by Australian members of Oosternina ca. 90 million years ago (mya) and at least five dispersal events between Asia and America ca. 63–55 mya via the Beringia land bridge. The timing of the Asia‐America faunal interchange corresponds to the hyperthermal climate of the Late Paleocene and Early Eocene that allowed the expansion of tropical and subtropical biomes towards polar regions. Diversification analyses revealed no effect of intercontinental dispersals on speciation or extinction rates and suggested a possible effect of declining global temperatures in the last 20 million years. [ABSTRACT FROM AUTHOR]

The evolution of the coleopteran suborder Adephaga is discussed based on a robust phylogenetic background. Analyses of morphological characters yield results nearly identical to recent molecular phylogenies, with the highly specialized Gyrinidae placed as sister to the remaining families, which form two large, reciprocally monophyletic subunits, the aquatic Haliplidae + Dytiscoidea (Meruidae, Noteridae, Aspidytidae, Amphizoidae, Hygrobiidae, Dytiscidae) on one hand, and the terrestrial Geadephaga (Trachypachidae + Carabidae) on the other. The ancestral habitat of Adephaga, either terrestrial or aquatic, remains ambiguous. The former option would imply two or three independent invasions of aquatic habitats, with very different structural adaptations in larvae of Gyrinidae, Haliplidae and Dytiscoidea. [ABSTRACT FROM AUTHOR]

Triassic fossils are rare but crucial for understanding the early evolution of large insect clades including beetles (Coleoptera). Their phylogenetic assignment is problematic because of fragmentary preservation, yet crucial for the correct use of the information they provide. Here an analysis is presented of the phylogenetic position of Leehermania prorova, the Late Triassic compressed fossil which was described and hitherto widely used as the oldest representative of Staphylinidae (rove beetles) in the suborder Polyphaga. By contrast with the intuitive character assessment made in the original description, a phylogenetic analysis of Leehermania is performed using an extensive morphological matrix of extant Coleoptera provided by the Beetle Tree of Life project, constrained in view of the latest relevant molecular phylogenies. As a result, Leehermania is identified as an extinct lineage within the beetle suborder Myxophaga, closest to the modern family Hydroscaphidae. Excluding Leehermania from Staphylinidae and placing it in Myxophaga amends erroneous assumptions about early diversification of rove beetles and enhances our views of the evolutionary history of Coleoptera. [ABSTRACT FROM AUTHOR]

Hydrophilidae (water scavenger beetles) is well known as an aquatic beetle family; however, it contains ca. 1,000 secondarily terrestrial species derived from aquatic ancestors. The New Zealand endemic genus Rygmodus White is a member of the hydrophilid subfamily Cylominae, which is the early-diverging taxon of the largest terrestrial lineage (Cylominae + Sphaeridiinae) within the Hydrophilidae. In this paper we report that Rygmodus beetles are pollen-feeding flower visitors as adults, but aquatic predators as larvae. Based on analyses of gut contents and a summary of collecting records reported on museum specimen labels, adult Rygmodus beetles are generalists feeding on pollen of at least 13 plant families. Rygmodus adult mouthparts differ from those of other (saprophagous) hydrophilid beetles in having the simple scoop- like apex and mola with roughly denticulate surface, resembling the morphology found in pollen-feeding staphylinid beetles. Larvae were found along the sides of streams, under stones and in algal mats and water-soaked moss; one collected larval specimen was identified using DNA barcoding of two molecular markers, mitochondrial cytochrome oxidase 1 (cox1) and nuclear histone 3 (H3). Larvae of two species, Rygmodus modestus and Rygmodus sp., are described in detail and illustrated; they closely resemble ambush-type predatory larvae of the hydrophilid tribe Hydrophilini in the head morphology. Rygmodus is the only known hydrophilid beetle with adults and larvae inhabiting different environments. [ABSTRACT FROM AUTHOR]

The author refers to the issues faced by researchers while performing molecular dating analyses for beetles focusing on the analyses of beetles from the the Early Permian period to the Late Permian period. The author talks about developments in molecular dating analyses that investigates the effects of fossil selection and estimation of divergence times. The author compares their research with an original chronogram and their analysis.

The phylogeny and evolutionary history of the water scavenger beetles ( Coleoptera: Hydrophilidae) are inferred from comprehensive analyses of DNA sequence data from the mitochondrial genes COI, COII and 16S and the nuclear genes 18S, 28S and arginine kinase. Bayesian and maximum parsimony analyses included 151 taxa, representing all subfamilies, tribes and subtribes that have ever been proposed in the family, as well as representatives of the hydrophiloid families Helophoridae, Hydrochidae, Spercheidae, Epimetopidae and Georissidae. The resulting well-supported trees strongly disagree with prior classifications of the Hydrophilidae, suggesting that the smaller subfamilies ( Horelophinae, Horelophopsinae and Sphaeridiinae) are derived from within the larger Hydrophilinae. The existing tribal classification is more compatible with our results, but many significant differences are evident. Here, we present a new classification of the Hydrophilidae comprising 6 subfamilies and 12 tribes. Each subfamily and tribe is reviewed in detail with (i) a morphological diagnosis, including known or putative morphological synapomorphies, (ii) its taxonomic circumscription, including genera not included in our analyses, and (iii) a review of its general biology and geographic distribution. A new identification key to subfamily and tribe based on adult morphology is also provided. The newly adopted classification requires the following taxonomic changes: the subfamily Hydrophilinae sensu n. is redefined to include only the tribes Amphiopini stat.n. (removed from the synonymy with the Chaetarthriini), Berosini, Laccobiini, Hydrophilini and Hydrobiusini (= Sperchopsini syn.n.); the subfamily Chaetarthriinae stat.n. is removed from synonymy with the Hydrophilinae and includes the tribes Chaetarthriini and Anacaenini (= Horelophinae syn.n.); the Acidocerinae stat.n. (= Horelophopsinae syn.n.) and Rygmodinae stat.n. (= Andotypini syn.n., Borborophorini syn.n. and Tormissini syn.n.) are elevated to subfamily rank; and the subfamily Enochrinae subfam.n. is established for the genus Enochrus and its relatives. The implications for the morphological evolution, ecological transitions and biogeography of the family are discussed. [ABSTRACT FROM AUTHOR]

We performed a phylogenetic analysis focused on the hydrophiloid family Helophoridae (Coleoptera: Polyphaga) in order to test the phylogenetic position of selected Mesozoic fossils assigned to the Hydrophiloidea. The analysis is based on 92 characters of larvae and adults, and includes all extant subgenera of Helophorus and representatives of all other extant hydrophiloid families. Based on this analysis, we provide additional evidence for the monophyly of the helophorid lineage containing the families Helophoridae, Georissidae and Epimetopidae, as well as the first hypothesis on the phylogenetic relationships within Helophorus, revealing three main clades: Lihelophorus, Rhopalohelophorus and the clade of sculptured small subgenera; the subgenera Helophorus s.str., Gephelophorus, Trichohelophorus and Transithelophorus are recognized as paraphyletic or polyphyletic. Inclusion of fossil species in the analysis reveals the Mesozoic genera Hydrophilopsia Ponomarenko, Laetopsia Fikáček et al. (adult forms) and Cretotaenia Ponomarenko (larval form) as basal extinct clades of the helophorid lineage, the former genus Mesosperchus Ponomarenko as containing probable stem taxa of Helophorus and the former genus Mesohelophorus Ponomarenko as a member of the Helophorus clade containing extant sculptured subgenera. The extant subgenus Thaumhelophorus syn.nov. is synonymized with Rhopalohelophorus. Our results show that the family Helophoridae may be dated back to the late Jurassic ( c. 150 Ma) and the extant clades of Helophorus back to the Early Cretaceous ( c. 136 Ma). The basal groups of Helophorus and the supposed basal extinct lineages of the helophorid lineages are shown to be aquatic as adults. A single origin of trichobothria and ventral hydrophobic pubescence in the common ancestor of the Hydrophiloidea is hypothesized, indicating ancestral aquatic habits in the adult stage for the whole Hydrophiloidea. [ABSTRACT FROM AUTHOR]

Fossil water scavenger beetles (Coleoptera: Hydrophilidae) of the latest Oligocene Rott Formation are revised, based on the examination of the type specimens, as well as numerous additional material from Statz (Los Angeles) and Kastenholz (Bonn) collections. Seven hydrophilid species are recognized, five of which are reliably attributed to the following genera: Berosus morticinus (von Heyden and von Heyden, 1866), Paracymus excitatus (von Heyden and von Heyden, 1866), Paracymus sp., Hydrobiomorpha fraterna (von Heyden, 1859), and Hydrophüus rottensis (Statz, 1939). Coccinella? protogaeae Germar 1837 is attributed to the subtribe Hydrophilina, and Cymbiodyta? austera Statz 1939 to the subfamily Hydrophilinae. Hydrous ebeninus Statz 1939 and Paracymus excitatus (form 3) are excluded from the Hydrophiloidea. Berosus capitatus Statz 1939 is synonymized with Berosus morticinus, and Hydrous neptunus von Heyden and von Heyden 1866 with Hydrobiomorpha fraterna. Lectotypes of Philydrus morticinus von Heyden and von Heyden 1866 and Hydrous ebeninus Statz 1939 are designated. The significance of the hydrophilid fossils for paleoecological reconstructions of the former Rott Lake is briefly discussed. [ABSTRACT FROM AUTHOR]