We use integrative taxonomy to elucidate species boundaries of the plant bug genus Pseudoloxops (Kirkaldy 1905) in the Austral and Society archipelagos of French Polynesia. We operationalize the unified species concept by treating each individual as a potential species and then establish initial groupings (putative species) following statistically highly-supported reciprocal monophyly of individuals in a phylogenetic analysis of CO1, 16S, and 28S gene fragments. We then test our species hypotheses against additional lines of evidence from geometric morphometrics, genetic distance, discrete genitalic morphology, plant association, and geographic distribution partitions. Twenty species endemic to French Polynesia are recognized as follows: Pseudoloxops aama Balukjian & Van Dam, sp. nov., Pseudoloxops anaana Balukjian & Van Dam, sp. nov., Pseudoloxops baileyi Balukjian & Van Dam, sp. nov., Pseudoloxops chastaoliancai Balukjian & Van Dam, sp. nov., Pseudoloxops harrisonfordi Balukjian & Van Dam, sp. nov., Pseudoloxops kamalaharrisae Balukjian & Van Dam, sp. nov., Pseudoloxops oboyskii Balukjian & Van Dam, sp. nov., Pseudoloxops papepihaa Balukjian & Van Dam, sp. nov., Pseudoloxops puarata Balukjian & Van Dam, sp. nov., Pseudoloxops raimana Balukjian & Van Dam, sp. nov., Pseudoloxops ravataputuarai Balukjian & Van Dam, sp. nov., Pseudoloxops simberloffi Balukjian & Van Dam, sp. nov., Pseudoloxops tairoto Balukjian & Van Dam, sp. nov., Pseudoloxops temehanirahi Balukjian & Van Dam, sp. nov., Pseudoloxops tiapai Balukjian & Van Dam, sp. nov., Pseudoloxops toparaamahana Balukjian & Van Dam, sp. nov., Pseudoloxops tupapaau Balukjian & Van Dam, sp. nov. New synonyms are proposed for Pseudoloxops flavus (Knight, 1937) [=Pseudoloxops rubrocuneatus (Knight, 1937)] and Pseudoloxops adamsoni (Knight, 1937) [= Pseudoloxops nigribasicornis (Knight, 1937) and = Pseudoloxops tahiticus (Knight, 1937)]. Pseudoloxops rubroclavus (Knight, 1937) is redescribed.

The Afrotropical Cerurinae (Notodontidae) genera Cerurina Kiriakoff and Afrocerura Kiriakoff are revised. Historically, significant confusion has existed surrounding the identities of members of these 2 closely related genera. Using morphology and genetic data derived from mitochondrial COI barcodes and anchored hybrid enrichment nuclear genomics, we present an integrated taxonomic approach. Upon examining all types, historical material in global collections, and numerous recently collected specimens, we are able to associate available names with the taxa in these genera as well as describe four new species of Afrocerura for which no names were available. Historical misidentifications are also addressed. For nearly all species, both sexes and their genitalia are figured. In total, we recognize one species in Cerurina with 2 subspecies: C. marshalli marshalli Hampson (type species) and C. marshalli cameroona (Bethune-Baker) comb. n., and 8 species in Afrocerura: A. leonensis (Hampson) (type species), A. takanoi sp. n., A. bifasciata (Janse), A. inexpectata sp. n., A. tanganyikae Kiriakoff stat. n., A. ethiopica sp. n., A. thomensis (Talbot) and A. smithi sp. n. Color photos of C. m. cameroona larvae are presented for the first time and are compared to larvae of C. m. marshalli.

Delimitation of allopatric populations into species remains subjective and largely arbitrary. Many cold-adapted species from the sub-Arctic and Central and Southern European Mountain systems provide excellent models to study allopatry problem due to their patchy distributions.The same concerns many Holarctic species, which frequently show varying degrees of differentiation between continents. In this study, we analyze high-throughput target enrichment data for 10 groups of Arctic-alpine and Holarctic lepidopteran species sampled from different regions across the Holarctic realm, i.e., Fennoscandia, European Alps, Altai Mountains, and North America. We first aimed to assess whether the genetic differences in the nuclear genome reflected observed DNA barcode divergences and, secondly, whether the gap between population and species-level differences can be reliably dissected using genomic data. We compared the phylogenetic trees and uncorrected pairwise genetic distances obtained from target enrichment and mitochondrial COI barcodes and performed a suite of population genetic and species delimitation analyses to further explore patterns of intraspecific variation in our study species. We observed that in about one-half of the cases, DNA barcodes showed phylogenetic relationships similar to the target enrichment markers. Nuclear genetic differentiation varied among the populations analyzed, from low differentiation of geographically separated populations to the deeper separation of some Nearctic populations and Arctic-alpine disjunction in the populations from Fennoscandia and Southern European mountains. Our results highlight the need for consistent delimitation of allopatric populations, especially given the prevalence of distributional discontinuities across species. Large sets of standard genetic markers provide a very promising avenue towards this goal.

Parallel or convergent evolution may result in phenotypically closely similar species. Many studies have reported that using solely traditional external morphological features can result in misidentification. Here, we discuss using the reproductive systems and immature developmental stages for scientific classification in Eupelmidae (Hymenoptera: Chalcidoidea), exemplifying with Anastatus Motschulsky and Mesocomys Cameron (Eupelmidae, Eupelminae). Results show that there are at least 6 distinct differences in the immature stages and the reproductive systems of the adults between species of the 2 genera: (1) the terminal ends of the left and right ovarioles are connected together in the studied species of Anastatus but not in Mesocomys, (2) the base of the lateral oviduct of Anastatus has a diverticulum that is lobate-shaped, whereas this diverticulum is spherical in Mesocomys, (3) the peduncle of the egg of Anastatus is significantly longer than that of Mesocomys, (4) the head capsule of the terminal instar larvae of Anastatus is uniformly translucent, whereas in Mesocomys it has a brown pattern, (5) the ocelli of the Anastatus pupa are smooth and slightly raised whereas the ocelli of Mesocomys each have a long filament each, and (6) the phallobase of adult male Anastatus is sharp basally but rounded in Mesocomys. Our findings not only provide novel insights for the differentiation of similar genera that can be difficult to distinguish in the immature stages but also provide a more comprehensive theoretical basis for clarifying the evolutionary and phylogenic status of Anastatus and Mesocomys.

In recent years, Japanese oak wilt causing mass mortality of oak trees has exhibited a significant geographical expansion. Understanding the formation history of current local populations of Platypus quercivorus Murayama, a vector of Japanese oak wilt, is important foundational knowledge for effectively preventing forest damage. In this study, we used genome-wide single nucleotide polymorphism data to infer the population genetic structure and historical demography of P. quercivorus populations in eastern Japan, where Japanese oak wilt is rapidly expanding.We found at least 3 distinct genetic groups, each of which caused Japanese oak wilt in different areas.The supported scenario suggests that 1 of 2 genetic groups in the northeast first diverged from the ancestral population, then the other group diverged from the southwestern population, followed by gene flow between the 2 groups. Recent admixtures of the 2 northeastern groups were identified at certain sites.The geographic genetic structure of the populations suggested that each genetic group experienced recent range expansion. Although genetically independent populations had caused oak tree mass mortality in their original distribution range, our results support the hypothesis that the recent geographic expansion of Japanese oak wilt outbreaks is attributed to the range expansion of these P. quercivorus groups.

Cicadellidae (leafhoppers) may be the most diverse and abundant insect herbivores in terrestrial ecosystems worldwide, with more than 23,000 described species in 20 extant subfamilies. Although prior studies have supported the monophyly of most recognized subfamilies, relationships among these groups remain inconsistently resolved and previous molecular phylogenies have failed to support the monophyly of a few subfamilies. To help address this deficiency, we combined 24 new complete mitogenomes representing 6 previously unsequenced subfamilies and 13 tribes with previously available data to create a dataset of 79 cicadellid taxa representing 16 subfamilies for phylogenetic analysis. The new analyses confirm that leafhopper mitochondrial genomes are highly conservative in overall structure, with only a few rare rearrangements of tRNAs. All phylogenetic analyses consistently supported the monophyly of previously recognized cicadellid tribes for which more than 1 representative was included and all of the included subfamilies were also consistently recovered as monophyletic with the exception of Aphrodinae and Eurymelinae. Bayesian inference and Maximum Likelihood analyses with site-homogeneous models are only slightly affected by nucleotide compositional heterogeneity and yield more stable phylogenetic relationships of family-group taxa than analyses with a heterogeneous-site mixture model using PhyloBayes. Molecular divergence time estimates indicate that the main lineages of Cicadellidae, most corresponding to recognized subfamilies, diverged during the Cretaceous period (93–121 Mya).

Genital morphology, a cornerstone in taxonomy that predates Linnaeus's Systema Naturae, is vital for species delimitation. However, the widely accepted paradigm that genitalia are taxonomically informative lacks robust testing between closely related species, and supporting evidence is often limited to taxonomic literature in which genitalia are assumed a priori to be species-specific. The cosmopolitan ant genus Nylanderia Emery includes 123 described species, with most in the Neotropics still undescribed. Workers are often morphologically cryptic, and males are rare in collections but required for morphological delimitation. Using Ultraconserved Elements (UCEs) from 236 samples, including 53 Neotropical Nylanderia species, we reconstructed a phylogenetic framework to compare the genitalia (gonopods) of males collected alongside workers. We used geometric morphometrics on images of slide-mounted genitalia from 16 species and nano-CT scans of Nylanderia fulva (Mayr) and Nylanderia pubens (Forel) genital capsules and interpreted results considering phylogeny under maximum likelihood and the multispecies coalescent. We found strong morphological and molecular support for 2 distantly related American clades, identifiable by gonopod shape, with significant differences observed among most species. Three previously reported COI clades of N. fulva were not supported as monophyletic, nor were their gonopods significantly different. However, N. pubens was supported as distinct by all phylogenetic and 3DGM results. Our findings emphasize the importance of male genitalia for delimiting species boundaries and revising Neotropical Nylanderia. Given their importance, particularly in morphologically cryptic taxa, we recommend a greater focus on linking male and worker phenotypes, which can be facilitated through comprehensive nest series collection.

Graphical Abstract

“Infinite diversity in infinite combinations.”– Leonard Nimoy (as Spock) in ‘Star Trek: The Original Series’ (1968)

The geographic distribution and systematics of many groups of insects are still understudied across large geographic areas of the Iberian Peninsula. This lack of knowledge and the fact that many species have a complex evolutionary history due to the existence of “refugia within refugia” have hindered the taxonomic description of the true biodiversity in the Iberian Peninsula. Here, we discuss the evolutionary history of a flightless Iberian bush-cricket Antaxius spinibrachius (Fischer, 1853) using 1 nuclear and 2 mitochondrial markers. We applied species distribution modeling to design sampling strategies in climatically favorable areas and to detect missing isolated populations or unknown lineages. Following the species distribution modeled using all of the presence records available, we discovered 4 new isolated populations in Sierra Madrona, Serra de São Mamede, Sierra de Montánchez, and Sierra de la Demanda. Phylogenetic analyses recovered 2 major Pliocene lineages with a north–south geographic speciation pattern in the Iberian Peninsula. This north–south vicariant event split the common ancestor of these species on either side of the Tagus Valley, probably associated with the Pliocene climate change and the reorganization of paleobasins of the western Iberian Peninsula during the Miocene–Pliocene. We described the southern Iberian Plateau lineage of Antaxius as a new species of bush-cricket based on phylogenetic and morphological evidence, Antaxius oretanus sp. nov. We assessed the conservation status of the new species as “VU B2ab(iii,v)” under the IUCN criteria.

Graphical Abstract

Bembidion Latreille (Coleoptera: Carabidae) is a genus of small ground beetles containing about 1,380 species. To test previous phylogenetic hypotheses about deeper lineages of Bembidion and near relatives, we recover and examine over 1,800 nuclear protein-coding loci from 33 species representing the main lineages of Bembidion, 10 species of other bembidiine genera, and 7 outgroups. We find that Bembidion exclusive of subgenus Phyla Motschulsky is monophyletic, and we reclassify Phyla as a separate genus. Within Bembidion we find 2 dominant clades, the Bembidion superseries (containing about 490 species in the subgenera Eupetedromus Netolitzky and Lindrochthus Maddison, the Philochthus Stephens complex, and the Bembidion series), and the Ocydromus Clairville superseries (containing almost all other Bembidion representing about 840 species).The only known lineages within Bembidion outside of these superseries are subgenus Hoquedela Müller-Motzfeld and the Desarmatocillenus Netolitzky complex, which combined contain less than 30 species. Most clades are insensitive to variations in analyses and hold up under different sets of taxa and loci, analyses at the nucleotide or amino acid levels, and different analytical methods (maximum likelihood, including posterior mean site frequency analyses, Bayesian analyses, invariant-based methods, and those that consider incomplete lineage sorting). Despite the clarity achieved in most aspects of the phylogeny, there are several unresolved regions, notably the relationships of Desarmatocillenus, Hoquedela, and Phyla to other bembidiines. A divergence dating analysis suggests that crown Bembidion is about 48 million years old (95% confidence intervals 40–58 Ma), and that the 2 large superseries are about 38 million years old (95% confidence intervals about 29–47 Ma).

Graphical Abstract