A morphologically unusual fossil true bug genus, Palaeotanyrhina Poinar, Brown & Kóbor, 2022, placed into Cimicomorpha: Reduvioidea by its authors, is revisited based on an inclusion in mid-Cretaceous Burmese amber. The original description is supplemented with additional details and corrections. It is demonstrated that the placement of Palaeotanyrhina into Cimicomorpha was based on misinterpretations of the morphology of the holotype, and the genus is a member of the infraorder Leptopodomorpha. A phylogenetic analysis is provided for fossil and extant taxa of Leptopodomorpha. Parvilepta Yu, Zhuo & Chen, 2023, Cretaleptus Sun & Chen, 2019, Macrolepta Yu, Zhuo & Chen, 2023 (currently members of Leptopodidae: Leptosaldinae) and Palaeoleptus Poinar, 2009 (the type genus of Palaeoleptidae) are demonstrated to be phylogenetically closely related to Palaeotanyrhina. All the above mentioned genera are recognized to represent stem-group members of Leptopodomorpha: Leptopodidae: Leptopodinae: Leptopodini, and accordingly, they are transferred to the latter tribe. The following new subjective synonyms are proposed: Leptopodidae: Leptopodinae: Leptopodini Brullé, 1836 = Palaeoleptidae Poinar, 2009, syn. nov. = Palaeotanyrhinidae Poinar, Brown & Kóbor, 2022, syn. nov. Based on the analytic results, the subfamilies Leptosaldinae and Leptopodinae of Leptopodidae and the tribes Leotichiini and Leptopodini of Leptopodinae are considered valid, redefined, and a list of their included genera and species are provided. Arguments are provided in support of the placement of Leptosaldinea Popov & Heiss, 2016, formerly placed into Leptosaldinae, into the infraorder Dipsocoromorpha.

The genus Cheguevaria (Kazantsev 2007) is currently comprised of three species which are endemic to the Greater Antilles: Cheguevaria angusta Kazantsev, 2007 (Hispaniola), Cheguevaria taino Kazantsev, 2007 and Cheguevaria montana Kazantsev, 2008 (both from Puerto Rico). Cheguevaria is the sole member of Cheguevariinae, and a previous morphology-based phylogenetic hypotheses suggested a close relationship with the subfamily Amydetinae. Recent collecting trips to Puerto Rico and the survey of other scientific collections allowed us to identify and locate more specimens of the genus, including several color morphs of specimens tentatively identified as C. montana. We used this material to revise the genus, and to describe Cheguevaria cubensis new species, the first record of the genus from Cuba. We also produced DNA barcodes based on partial cytochrome c oxidase subunit 1 (COI), which were used to investigate the species limits within color morph species of C. montana. Our results showed a high level of genetic stability in those color morphs, indicating that all specimens belong to the same species. We present a discussion to explain possible scenarios leading to such variation in color patterns. We also generated amplicons for two specimens of Amydetinae, represented by two Amydetes Illiger, 1807 species, and we tested their relationship with Cheguevaria in a phylogenetic context based on a four gene dataset. Our analyzes indicated a disjoint relationship between Cheguevaria and Amydetes, corroborating previously published morphology-based phylogenies, and we maintained the status of Cheguevaria as an independent lineage within Lampyridae.

The hoverflies are one of the most abundant families in Diptera and an important category of resource insects. They can provide important ecosystem services such as pollination and beneficial biological control agents. In the four-subfamily classification system of the Syrphidae, the monophyly of the Eristalinae within Syrphidae has not been recovered. In this study, we performed new sequencing and analysis of low-coverage whole genomes for 25 species of Syrphidae. Phylogenetic reconstructions were conducted based on different datasets and analytical strategies. Across all our analyses, the monophyly of the Syrphinae is supported but we do not recover the monophyly of the Eristalinae, consistent with previous research findings. Additionally, employing fossil calibrations for divergence time estimation, our results indicate that the origin of the Syrphidae occurred between the Albian and Aptian stages, approximately between 120.5 and 109.3 million years ago, the origin of the subfamily Syrphinae was dated in the Early Eocene, about 50.8–47.8 million years ago, in accordance with the diversification of their prey. This study will help us understand the higher-level phylogenetic and evolutionary relationships within Syrphidae.

Graphical Abstract

Sciaroidea is a megadiverse clade within Diptera that exhibits diverse larval feeding modes. In this study, we explored the phylogenetic relationships and evolution of larval feeding modes within the superfamily using a fossil-calibrated time tree. We found that filtering out potentially fast-evolving sites altered the family-level tree topology, and that species within Sciaroidea incertae sedis might be crucial in determining the general tree topology.The most recent common ancestor of Sciaroidea was inferred to have originated in the UpperTriassic (∼225 Ma). A major radiation of families occurred from the UppermostTriassic to the Lowermost Jurassic (190–200 Ma). The ancestral larval feeding mode was inferred to be mycophagy. Most families retained this feature with only minor transitions occurring in some clades; however, Cecidomyiidae and Keroplatidae went through notable shifts in larval feeding mode. Cecidomyiidae underwent a transition from mycophagy to phytophagy in the Lower Cretaceous, in line with angiosperm radiation as suggested in previous studies.The larvae of stem Keroplatidae were inferred to be predators since the Jurassic. A transition back to mycophagy occurred within the subfamily Keroplatinae during the Paleogene to Uppermost Cretaceous, coinciding with the origin and radiation of species-rich mycophagous clades of other sciaroid families. Our study highlights the importance of taxon sampling and sequence filtering in phylogenetic analyses of Sciaroidea. We suggest, based on temporal patterns of lineage diversification, that the evolution of larval feeding modes within the group might be correlated with the diversification of mushroom-forming fungi and angiosperms.

The Neotropics harbor a diverse array of flora and fauna shaped by a complex geological and climatic history. It includes marine invasions, pulses of Andean uplift, glaciations, and the uplift of the Panama Isthmus. These events have shaped organism distribution, which can be described by methods of historical phylogeography. However, the evolutionary history of nonvertebrate organisms in the Neotropics is still largely unknown. This applies to termites, which are particularly diverse and ecologically important. The phylogeography of the soil-feeding termites Embiratermes neotenicus and Embiratermes chagresi (Termitidae: Syntermitinae) was studied across their whole distribution range, using samples of 243 colonies from eight countries. Analyses based on mitochondrial DNA fragments, microsatellite loci, and complete mitochondrial genomes revealed 4 major mitochondrial haplogroups (H1–H4). The H4 haplogroup occurs in northeastern Brazil and diverged first. The other groups appear to be associated with the Pebas System and marine invasions during the Miocene, which may have contributed to the separation of the ancestral population along a north–south axis. The H1 haplogroup was affiliated with E. chagresi. The phylogenomic analysis estimated the divergence of E. chagresi from the other groups to 5 million years ago, aligning with the northern cordillera uplift during the Miocene. Microsatellite data highlighted the isolation of E. neotenicus populations in Suriname and French Guiana, possibly linked to Pleistocene climatic fluctuations. Our study provides insights into the evolutionary history of these species, contributing to a better understanding of how geological and climatic events have influenced species evolution in the Neotropics.

Graphical Abstract

Despite the great advances in salticid systematics, the phylogeny of the subtribe Dendryphantina remains in part unresolved and many of the taxonomic boundaries of the genera are still problematic since previous systematic phylogenetic studies relied on sparse taxonomic samplings. Thus, further in-depth studies of the different groups are required to establish the generic boundaries and to piece together the genus-level relationships. Here, we examine more closely the phylogeny of the large-bodied North American jumping spiders and their relatives: Paraphidippus, Pelegrina, Phidippus, Beata sensu stricto, Metaphidippus manni group species, Dendryphantes nigromaculatus, Eris militaris, and Nagaina incunda. We elucidate the relationships among the genera and test their monophyly, employing molecular data from the mitochondrial gene fragment cytochrome oxidase subunit I, and nuclear gene fragments from histone 3 and actin 5C, analyzed under maximum likelihood approaches. Based on our results, the North American species D. nigromaculatus is related to the Palearctic species of Dendryphantes. Meanwhile, the previously established relationship between the genera Phidippus, Paraphidippus, and Beata sensu stricto is confirmed, whereas Pelegrina, Eris militaris, Nagaina cf. incunda, and species from the Metaphidippus manni group form another clade. Within this clade, Pelegrina is nonmonophyletic and is closely related to the Metaphidippus manni group species, which indeed form a monophyletic group.Therefore, this study is crucial for singling out the taxa in need of revision, as well as consolidating important relationships within the subtribe Dendryphantina.

The first fossil rust fly (Diptera: Psilidae) from the Insect Bed of the Bembridge Marls of the Isle of Wight is also the first known fossil record of the subfamily Chylizinae. It is late Eocene: Priabonian in age, 34.2 Ma. Chyliza colenutti Ross, Zhou, Hoffeins & Crighton, sp. nov. is compared with 30 extant species of Chyliza and differs from them in having a relatively long 2nd basal cell compared to the discal cell. Some other fossil Acalyptratae records are reviewed and their probable ages updated. The phylogenetic position of the Psilidae is currently uncertain so the family may have appeared anytime from 70–40 million years ago.

Understanding the complexity of trophic interactions of parasitoid Hymenoptera remains a critical challenge in biodiversity research, particularly in vastly understudied dark taxa. Using Ceraphronoidea (Hymenoptera) as a case study, we conduct a comprehensive analysis of host associations at both genus level and species level across the four prominent genera AphanogmusThomson, 1858 (Ceraphronidae), Ceraphron Jurine, 1807 (Ceraphronidae), Conostigmus Dahlbom, 1858 (Megaspilidae) and Dendrocerus Ratzeburg, 1852 (Megaspilidae), drawing from an extensive synthesis of existing literature. We shed light on the ecological interactions and explore their potential to advance integrative taxonomic efforts within this moderately species-rich yet highly understudied taxon. Our analysis reveals a broad host range that spans up to nine insect orders with species from the four major ceraphronoid genera parasitizing dipteran and hymenopteran hosts. Notably, 80.8% of ceraphronoid species lack documented host associations, reflecting significant gaps in autecological knowledge, with rates varying significantly between the genera. Our findings highlight the urgent need to improve our understanding of host-parasitoid interactions beyond economically relevant species, emphasizing both the significance and the potential of this data for biodiversity research within taxonomically challenging taxa, particularly in times of escalating species decline.

Heavy metal pollution is pervasive in urban soils, and it can negatively impact the fitness of arthropods. Arthropod populations can evolve to become more tolerant or resistant to metals, but the mechanisms of these processes are understudied. Here, we tested the hypotheses of fixed adaptation and facultative adaptation in a lead (Pb)-exposure experiment using the progeny of field-collected Pardosa milvina spiders from urban (elevated soil Pb) and rural (background soil Pb) habitats. We predicted that spiders from both populations that were reared in the elevated Pb treatment would exhibit decreased body size in comparison to individuals reared in background Pb soil due to a facultative shift in metabolic investment from growth to Pb resistance, or, alternatively, that urban spiders would exhibit no change in body size across treatments, supporting fixed adaptation as a consequence of a legacy effect of urban Pb pollution. We found no evidence that exposure to elevated Pb soil had an effect on P. milvina's adult body size or survival, regardless of population origin. Our results indicate that the amount of Pb accumulated by the spiders was not sufficient to induce a measurable change in body size, or that there was a fitness cost that was not measured in the experiment, such as changes in fecundity or body condition. Overall, these findings do not provide support for fixed or facultative adaptation to Pb pollution in P. milvina; as such, future studies should investigate other possible tradeoffs, including changes in egg size, body weight, and foraging effort.

We tested the species hypotheses for 8 of the 9 Phloeosinus spp. inhabiting the Transition Zone of Mexico based on molecular and morphological data. The morphology was analyzed using various trait sources, considering the geographical variation for each taxon by mean multivariate analyses. Through genomic analyses using genotyping by sequencing paired-end data, including genetic structure, phylogenomic, and species delimitation analyses, we evaluate whether the taxonomic species correspond to well-structured lineages that are congruent with their morphological variation and taxonomic classification. Our results supported Phloeosinus baumanni, P. deleoni, P. serratus, and P. tacubayae as genetically differentiated and well-structured lineages. These species in addition to P. arizonicus, P. cristatus, P. spinosus, and P. taxodii tacodiicolens display discrete phenotypes, either in one or several components of their morphology and considering their geographical variation, thus agreeing with their taxonomic hypothesis. Phloeosinus serratus represents a special case of all the taxa analyzed. This species showed high morphological polymorphism associated with specimens from 3 host species and different localities. However, these correspond to a single panmictic genetic population, with varying degrees of intermixture, without phylogenetic lineages structured by the host. Thus, it corresponds to only one species with wide phenotypic plasticity likely associated with patchy areas of different host species. Phylogenomic topologies support at least 2 diversification hypotheses for Phloeosinus spp. in the MexicanTransition Zone; one of them implies the specialization of feeding preferences toward Cupressus, from Juniperus habits, and the other one the presence of 2 big clades specialized in Cupressus, and Juniperus spp., respectively.