The spider tree of life: phylogeny of Araneae based on target‐gene analyses from an extensive taxon sampling

Mystery on the Bounty: The family-level status of Pacificana cockayni Hogg, 1904 (Araneae)

The family-level placement of the species Pacificana cockayniHogg, 1904 (Araneae, Miturgidae) has been ambiguous for over a century, with the monotypic genus Pacificana initially placed in Agelenidae, later transferred to Amaurobioidinae (Anyphaenidae), and presently in Miturgidae. A recent work describing the male and molecular data consisting of a single mitochondrial gene, cytochrome c oxidase subunit I, confirmed that the species is part of the marronoid clade; however, these data did not result in a conclusive family-level placement. Here, we use low-coverage whole genome sequencing (lcWGS) combined with data from the Sequence Read Archive to infer a phylogeny from ultraconserved elements (UCEs) and six legacy Sanger loci. Indications of potential family placements from prior work and the topologies from this study support a transfer of Pacificana Hogg, 1904 to Cycloctenidae Simon, 1898 (new family placement).

Comparative mitogenomics of Cheiracanthium species (Araneae: Cheiracanthiidae) with phylogenetic implication and evolutionary insights

The genus Cheiracanthium C. L. Koch, 1839 is the most species-rich genus of the family Cheiracanthiidae. Given the unavailability of information on the evolutionary biology and molecular taxonomy of this genus, here we sequenced nine mitochondrial genomes (mitogenomes) of Cheiracanthium species, four of which were fully annotated, and conducted comparative analyses with other well-characterized Araneae mitogenomes. We also provide phylogenetic insights on the genus Cheiracanthium. The circular mitogenomes of the Cheiracanthium contain 37 genes, including 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNAs), two ribosomal RNA genes (rRNAs) and one putative control region (CR). All genes show a high A+T bias, characterized by a negative AT skew and positive GC skew, along with numerous overlapped regions and intergenic spacers. Approximately half of the tRNAs lack TΨC and/or dihydrouracil (DHU) arm and are characterized with unpaired amino acid acceptor arms. Most PCGs used the standard ATN start codons and TAR termination codons. The mitochondrial gene order of Cheiracanthium differs significantly from the putative ancestral gene order (Limulus polyphemus). Our novel phylogenetic analyses infer Cheiracanthiidae to be the sister group of Salticidae in BI analysis, but as sister to the node with Miturgidae, Viridasiidae, Corinnidae, Selenopidae, Salticidae, and Philodromidae in ML analysis. We confirm that Cheiracanthium is paraphyletic, for the first time using molecular phylogenetic approaches, with the earliest divergence estimated at 67 Ma. Our findings enhance our understanding of Cheiracanthium taxonomy and evolution.

On new spider species of the genus Episinus (Araneae, Theridiidae) from China and proposal of five species groups

Background

Currently, the genus Episinus Walckenaer, 1809 includes 64 described species mainly being distributed in Asia, Africa and the Americas, with 16 described species in China. During the recent surveys across various regions of China, we found three previously undescribed species which have been identified as belonging to Episinus.

New information

Three new species of Episinus Walckenaer, 1809 are described: Episinusanfu sp. nov. (♀) from Jiangxi Province, E.implicatus sp. nov. (♀) from Yunnan Province and E.pseudonubilus sp. nov. (♂♀) from Shaanxi Province. Based on morphological characteristics and previous studies, we further propose five species groups to accommodate the Chinese Episinus, including two species groups proposed by Liu et al. (2022). Detailed descriptions, photographs, hand drawings, DNA barcodes and a distribution map of the three new species are provided.

Reassessing the evolutionary relationships of tropical wandering spiders using phylogenomics: A UCE-based phylogeny of Ctenidae (Araneae) with the discovery of a new lycosoid family

Tropical wandering spiders (Ctenidae) are a diverse family of cursorial predators whose species richness peaks in the tropics. The phylogeny of Ctenidae has been examined using morphology and Sanger-based sequencing data, but these studies have been limited by taxon sampling and have often recovered low branch support for many intrafamilial phylogenetic relationships. Herein, we present the most extensive phylogenetic sampling of this family using genome-scale data, leveraging museum collections of all ctenid subfamilies from across the world. We obtained a well-resolved phylogeny of Ctenidae, with the majority of nodes showing maximal nodal support and topological congruence across different phylogenetic analyses. For the first time, we show with high support that Ancylometes is not within Ctenidae but is the sister lineage to all the remaining lycosoid families. Therefore, we propose Ancylometidae as a new family. We assess the phylogenetic position of Ctenidae within Lycosoidea using a variety of phylogenetic methods and tests, demonstrating that the previously proposed position of Ctenidae as the sister clade of Psechridae, based on phylotranscriptomic analyses, lacks phylogenetic support. As a new finding, this study shows that the subfamily Acantheinae, as currently delimited, is polyphyletic. Therefore, we erect the new ctenid subfamily Enoplocteninae to accommodate the Neotropical genera Enoploctenus, Chococtenus, and Phymatoctenus. Our phylogenomic results using UCE data resolve the position of several problematic genera (e.g., Califorctenus and Acantheis) and add support to other parts of the tree that received low support in the most recent Sanger-based phylogeny. We discuss some of the putative morphological synapomorphies of the main ctenid lineages within the phylogenetic framework provided by the molecular phylogenetic results of this study.

Molecular phylogenetics of nursery web spiders (Araneae: Pisauridae)

Pisauridae Simon, 1890, or nursery web spiders, are a large family with a worldwide distribution and very diverse life history strategies. Despite being named for their nursery webs, similar structures are built by some members of Ctenidae, Trechaleidae, and Oxyopidae. Pisauridae has no known morphological synapomorphies that circumscribe all members of the family, and delineation of subfamilies has been a longstanding issue. In addition, several recent molecular phylogenetic studies have called into question the monophyly of Pisauridae. Here, we infer a phylogeny of Pisauridae with nine genetic markers (12S, 16S, 18S, 28S, actin, COI, histone H3, ITS2, and NADH) combined with ultraconserved elements (UCEs) to test the monophyly of the group and determine intrafamilial relationships. Our study includes a total of 81 terminals (59 of them pisaurids). Our maximum likelihood and gene coalescence analyses strongly suggest that as currently circumscribed, the family Pisauridae is not monophyletic. To circumscribe Pisauridae as a monophyletic group, based on our molecular results, we propose the restoration of the family Dolomedidae Simon, 1876 (rank resurrected) to include the genera DolomedesLatreille, 1804 and BradystichusSimon, 1884. In addition, based on morphological evidence, we also place in Dolomedidae the genera MegadolomedesDavies & Raven, 1980; Tasmomedes Raven, 2018; Mangromedes Raven, 2018; OrnodolomedesRaven & Hebron, 2018; and CaledomedesRaven & Hebron, 2018. We provide a phylogenetic delimitation of the three subfamilies of Pisauridae: Halinae, Thaumasiinae, and Pisaurinae. Ten pisaurid genera are deemed incertae sedis in terms of their placement. In light of our hypothesized molecular phylogeny, we discuss the morphological characters and putative synapomorphies of Pisauridae and propose diagnostic characters for its subfamilies and for the family Dolomedidae, along with taxonomic notes about genera not included in our study.

Olfaction with legs-Spiders use wall-pore sensilla for pheromone detection

The sense of smell is a central sensory modality of most terrestrial species. However, our knowledge of olfaction is based on vertebrates and insects. In contrast, little is known about the chemosensory world of spiders and nothing about how they perform olfaction despite their important ecological role. The orb-weaving spider Argiope bruennichi lends itself to an in-depth study on olfaction as it is one of the few spider species whose volatile sex pheromone, emitted by females to attract males, is known. We combined ultrastructural and electrophysiological analyses and found that previously overlooked sensilla with wall pores are abundant on all walking legs of A. bruennichi males. We compared the ultrastructure of these wall-pore sensilla with those known to perform olfaction in insects, exploring similarities and differences. Electrophysiological single sensillum recordings demonstrated that the wall-pore sensilla in A. bruennichi respond highly sensitive and in a concentration-dependent manner to the sex pheromone. Our study demonstrates male-specific sensilla for detecting signaling females, whereas females and subadult males are devoid of wall pore sensilla. In a preliminary comparative morphological analysis using 19 species from 16 spider families, we found that wall-pore sensilla occur in male spiders from most, but not in basally branching clades or in Salticids, suggesting that wall-pore sensilla evolved at least once within spiders and were lost at least once. This research significantly expands our knowledge of the sensory ecology of spiders, will stimulate studies on the diversity and function of sensilla, as well as studies on the evolution of olfaction in arthropods.

The world's most venomous spider is a species complex: systematics of the Sydney funnel-web spider (Atracidae: Atrax robustus)

The Sydney funnel-web spider Atrax robustus O. Pickard-Cambridge, 1877 is an iconic Australian species and considered among the most dangerously venomous spiders for humans. Originally described in 1877 from a single specimen collected in "New Holland", this spider has a complex taxonomic history. The most recent morphological revision of funnel-web spiders (Atracidae) lists this species as both widespread and common in the Sydney Basin bioregion and beyond, roughly 250 km from the Newcastle area south to the Illawarra, and extending inland across the Blue Mountains. Morphological variability and venom diversity in this species appear to be unusually high, raising questions about species concepts and diversity in these spiders. In this study, we use a combination of molecular phylogenetics, divergence time analyses and morphology to establish the Sydney funnel-web spider as a complex of three species. The "real" Sydney funnel-web spider Atrax robustus is relatively widespread in the Sydney metropolitan region. A second species, Atrax montanus (Rainbow, 1914), which is revalidated here, overlaps but mainly occurs further south and west, and a third larger species, Atrax christenseni sp. nov., is found in a small area surrounding Newcastle to the north. The revised taxonomy for funnel-web spiders may have practical implications for antivenom production and biochemical studies on spider venoms. Although no human fatalities have occurred since the development of antivenom in the 1980s, antivenom for Sydney funnel-web spiders might be optimized by considering biological differentiation at the species level.

Molecular Phylogenetic Relationships Based on Mitogenomes of Spider: Insights Into Evolution and Adaptation to Extreme Environments

In this study, we performed a comparative analysis based on a total of 255 spider mitogenomes and four outgroups, of which the mitogenomes of 39 species were assembled de novo, to explore the phylogenetic relationships and the adaptive evolution of mitogenomes. Results showed that Argyroneta aquatica had the longest mitochondrial length and the most pronounced codon preference to be UUA, followed by CCU. Codon usage frequencies were similar between families and codon usage in the mitogenome of spiders was mainly influenced by natural selection pressures rather than G/C mutation bias. Our phylogenetic topology clearly explained the evolutionary relationships among the spiders, and divergence time estimates indicated that the spiders originated in the early Devonian, and that the two clades of Mesothelae and Opisthothelae separated in the late Carboniferous. Ancestral range and trait reconstruction results supported the ancestral origin of spiders to the Devonian Nearctic realm, with the trapdoor being the original trait. Selection analysis detected positive selection signals in the ATP8 gene in Desis jiaxiangi. The ND5 gene is a convergent evolutionary gene between D. jiaxiangi and A. aquatica. Positive selection signals in the ATP8 gene and convergent selection sites in the ND5 gene may facilitate metabolic adaptation to the aquatic environment in two aquatic spiders. In conclusion, our analysis contributes to a better understanding of the taxonomic status, species diversity, mitochondrial characteristics, and environmental adaptations of these spiders.

Spider silk tensile performance does not correlate with web use

Spider silk is amongst the toughest materials produced by living systems, but its tensile performance varies considerably between species. Despite the extensive sampling of the material properties and composition of dragline silk, the understanding of why some silks performs better than others is still limited. Here, I adopted a phylogenetic comparative approach to reanalyze structural and mechanical data from the Silkome database and the literature across 164 species to (a) provide an extended model of silk property evolution, (b) test for correlations between structural and mechanical properties, and (c) to test if silk tensile performance differs between web-building and nonweb-building species. Unlike the common notion that orb-weavers have evolved the best-performing silks, outstanding tensile properties were found both in and outside the araneoid clade. Phylogenetic linear models indicated that the mechanical and structural properties of spider draglines poorly correlate, but silk strength and toughness correlated better with birefringence (an indicator of the material anisotropy) than crystallinity. Furthermore, in contrast to previous ideas, silk tensile performance did not differ between ecological guilds. These findings indicate multiple unknown pathways toward the evolution of spider silk tensile super-performance, calling for better integration of nonorb-weaving spiders in spider silk studies.

Scaling of the extended phenotype: convergent energetics from diverse spider web geometries

Organisms capture energy to support growth, survival and reproduction in diverse ways. Larger metazoans require less energy per unit time and mass than smaller ones. Thus, structures animals build to capture energy need not scale isometrically with body size. Web-building spiders use silk structures of diverse geometries to capture energy, including two-dimensional orbs in some families or three-dimensional tangles or sheet-and-tangles, in others. Despite this diversity, we show that energy consumption rate per unit mass scaled identically with body size across all web geometries with a less than 1 : 1 relationship to body size, as expected for metazoans from metabolic theory. Spiders thus appear to adjust the size and shape of their webs in precise ways to attain this relationship, including, as we show here, creating a hollow space within certain three-dimensional web types to maintain a constant prey capture surface area per unit spider mass as they grow in size without requiring more silk. Our findings show how the allometric relationship between energetic traits and body size can be mediated by extended phenotypes and suggest an equivalence paradigm akin to the equal fitness paradigm whereby the diverse adaptive strategies of organisms allow them to perform equally well in supplying a unit of mass the energy needed across a lifetime.

A targeted gene phylogenetic framework to investigate diversification in the highly diverse yet geographically restricted red devil spiders (Araneae, Dysderidae)

The family Dysderidae is a highly diverse group of nocturnal ground-dwelling and active-hunter spiders. Dysderids are mostly restricted to the Western Palearctic, and particularly rich and abundant around the Mediterranean region. Interestingly, the distribution of species richness among its 24 genera and three subfamilies is highly biased-80% of its 644 documented species belong to just two genera, Dysdera (326) and Harpactea (211). Dysderidae provides an excellent study case for evolutionary and ecological research. It includes cases of trophic specialization, which are uncommon among spiders, and exhibit other remarkable biological (e.g. holocentric chromosomes), behavioural (e.g. cryptic female choice), evolutionary (e.g. adaptive radiation) and ecological features (e.g. recurrent colonization of the subterranean environment). The lack of a quantitative hypothesis on its phylogenetic structure has hampered its potential as a testing ground for evolutionary, biogeographical and ecological hypotheses. Here, we present the results of a target, multi-locus phylogenetic analysis, using mitochondrial (cox1, 16s and 12s) and nuclear genes (h3, 28s and 18s), of the most exhaustive taxonomic sample within Dysderidae (104 spp.) to date and across related families (Synspermiata) (83 spp.). We estimate divergence times using a combination of fossil and biogeographic node calibrations and use this timeline to identify shifts in diversification rates. Our results support the monophyly of the Dysderidae subfamilies Rhodinae and Dysderinae but reject Harpacteinae as currently defined. Moreover, the clades recovered within Harpacteinae do not support its current taxonomy. The origin of the family most likely post-dated the break-up of Pangea, and cave colonization may be older than previously considered. After correcting for the taxonomic artefacts, we identified a significant shift in diversification rates at the base of the genus Dysdera. Although the unique coexistence of specialist and generalist diets within the lineage could be suggested as the potential driver for the rate acceleration, further quantitative analyses would be necessary to test this hypothesis.

A comparative morphology of trichobothrial bases in araneoid spiders and its significance for the phylogeny and system of the superfamily Araneoidea (Arachnida, Araneae)

Bothrial morphology was studied by SEM in 137 araneoid genera representing all 22 currently recognized extant families and all 42 conventional subfamilies of the Araneoidea. The ancestral type in the superfamily Araneoidea is a 'hooded' bothrium with a single well-developed transverse ridge, dividing its proximal and distal plates ('Erigone-type'); the advanced type is a solid dome-like bothrium without vestiges of the ridge ('Theridion-type'); there are several intermediate types reflecting various pathways and stages of the ridge reduction (united here as 'Argiope-type'). The parallel trends in bothrial evolution, recognized as continuous series from the ancestral type up to the advanced one through some intermediate stages, are distinguished in each of the seven main phylogenetic lineages of the superfamily: 'tetragnathoids', 'araneoids', 'cyatholipoids', and 'theridioids' possess a complete set of the three types, while 'malkariods', 'symphytognathoids'. and 'linyphioids' lack the advanced, dome-like type ('Theridion-type'). Only three taxa have been proposed earlier as the sister group of the superfamily Araneoidea: Nicodamoidea, Deinopoidea, and Leptonetoidea; morphology of bothria, as well as other cuticular microstructures, clearly supports the araneoid-nicodamoid relationship hypothesis, purely 'molecular' to date. Bothrial morphology provides the additional arguments for several taxonomic acts, e.g., for the reranking the Agnarsson's (2004) 'clade 35' (Theonoe, Carniella, Robertus, and Pholcomma) up to the Theonoeinae Simon, 1894, stat. nov., and for the revalidation the micropholcommatid Plectochetos Butler, 1932, gen. revalid. and zygiellid Parazygiella Wunderlich, 2004, gen. revalid.

Systematics of cybaeid spiders endemic to the Japanese Archipelago, and their historical biogeographic implications (Araneae: Cybaeidae)

The epigean and subterranean spiders of the genus Cybaeus L. Koch, 1868 are distributed in the Holarctic, and are highly diversified in western North America and Japan. More than 100 species have been described from the Japanese Archipelago and several species assemblages have also been recognised among the Japanese Cybaeus based on their morphological similarities. However, their phylogenetic backbone remains unclear. Moreover, genus-level classification of several of the Japanese species appear to be questionable. In this study we performed extensive molecular analyses of the family Cybaeidae in East Asia, mainly the Japanese Archipelago, to clarify their fundamental phylogenetic relationships. We also conducted a divergence time estimation to provide insights into their historical biogeography and evolutionary history. Our divergence dating results indicate that the diversification of the major lineages of the East Asian cybaeid spiders might be related to the opening of the Sea of Japan c .20million years ago. On the basis of the morphological evaluation and obtained phylogenies, some East Asian species formerly placed in Cybaeus are transferred to the cybaeid genera Allocybaeina Bennett, 2020, Sincybaeus Wang & Zhang, 2022 and Cybaeina Chamberlin & Ivie, 1932, i.e. Allocybaeina petegarina (Yaginuma, 1972), comb. nov., Sincybaeus monticola (Kobayashi, 2006), comb. nov., Sincybaeus rarispinosus (Yaginuma, 1970), comb. nov., Sincybaeus yoshiakii (Yaginuma, 1968), comb. nov., and Cybaeina whanseunensis (Paik & Namkung, 1967), comb. nov. Our results clarify the genus-level richness of cybaeids in the Japanese Archipelago for the first time, and reveal the fine-scale phylogenetic relationships of Cybaeus species endemic to the Japanese Archipelago and adjacent regions. ZooBank: urn:lsid:zoobank.org:pub:AF2A3C0E-7F0F-4253-85BA-D995A075F00D.

Spider's Silk as a Potential Source of Antibiotics: An Integrative Review

Spiders produce webs, which are still a largely unexplored source of antibacterial compounds, although the reports of its application in the medical field. Therefore, this study aims to present an integrative review of the antibacterial activity of spider webs. The research was conducted using Google Scholar, Scielo, Web of Science, PubMed, ScienceDirect, Medline EBSCO, LILACS, and Embase. The inclusion criteria were original articles written in English that studied the antibiotic properties of the web or isolated compounds tested. The studies were compared according to the spider species studied, the type of web, treatment of the sample, type of antimicrobial test, and the results obtained. Nine hundred and seventy-three publications were found, and after applying the inclusion and exclusion criteria, sixteen articles were selected. Bacterial inhibition was found in seven studies against various species of bacteria such as Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Salmonella Typhi, Bacillus megaterium, Listeria monocytogenes, Acinetobacter baumannii, Streptococcus pneumoniae, Pasteurella multocida, and Bacillus subtilis. Additionally, there was no apparent relationship between the proximity of the spider species evaluated in the studies and the presence or absence of activity. Methodological problems detected may affected the reproducibility and reliability of the results in some studies, such as the lack of description of the web or microorganism strain, as well as the absence of adequate controls and treatments to sterilize the sample. Spider webs can be a valuable source of antibiotics; however, more studies are needed to confirm the real activity of the web or components involved.

The Rediscovery of a Relict Unlocks the First Global Phylogeny of Whip Spiders (Amblypygi)

Asymmetrical rates of cladogenesis and extinction abound in the tree of life, resulting in numerous minute clades that are dwarfed by larger sister groups. Such taxa are commonly regarded as phylogenetic relicts or "living fossils" when they exhibit an ancient first appearance in the fossil record and prolonged external morphological stasis, particularly in comparison to their more diversified sister groups. Due to their special status, various phylogenetic relicts tend to be well-studied and prioritized for conservation. A notable exception to this trend is found within Amblypygi ("whip spiders"), a visually striking order of functionally hexapodous arachnids that are notable for their antenniform first walking leg pair (the eponymous "whips"). Paleoamblypygi, the putative sister group to the remaining Amblypygi, is known from Late Carboniferous and Eocene deposits but is survived by a single living species, Paracharon caecusHansen (1921), that was last collected in 1899. Due to the absence of genomic sequence-grade tissue for this vital taxon, there is no global molecular phylogeny for Amblypygi to date, nor a fossil-calibrated estimation of divergences within the group. Here, we report a previously unknown species of Paleoamblypygi from a cave site in Colombia. Capitalizing upon this discovery, we generated the first molecular phylogeny of Amblypygi, integrating ultraconserved element sequencing with legacy Sanger datasets and including described extant genera. To quantify the impact of sampling Paleoamblypygi on divergence time estimation, we performed in silico experiments with pruning of Paracharon. We demonstrate that the omission of relicts has a significant impact on the accuracy of node dating approaches that outweighs the impact of excluding ingroup fossils, which bears upon the ancestral range reconstruction for the group. Our results underscore the imperative for biodiversity discovery efforts in elucidating the phylogenetic relationships of "dark taxa," and especially phylogenetic relicts in tropical and subtropical habitats. The lack of reciprocal monophyly for Charontidae and Charinidae leads us to subsume them into one family, Charontidae, new synonymy.

Cupiennius spiders (Trechaleidae) from southern Mexico: DNA barcoding, venomics, and biological effect

Background

Members of the genus Cupiennius Simon, 1891 are categorized as wandering spiders and are part of the family Trechaleidae. The genomics and proteomics of Cupiennius spiders from North America remain uncharacterized. The present study explores for the first time molecular data from the endemic species Cupiennius chiapanensis Medina, 2006, and also presents new data for Cupiennius salei (Keyserling, 1878), both collected in southern Mexico.

Methods

In total, 88 Cupiennius specimens were collected from southern Mexico and morphologically identified. DNA was extracted and the mitochondrial COI fragment was amplified. COI sequences were analyzed, and a phylogenetic tree was inferred for species from the Americas. Genetic diversity was analyzed using haplotype networks and gene distances. Venom was obtained from C. chiapanensis and C. salei by electrostimulation. The venom was separated by HPLC, visualized using SDS-PAGE, and quantified for use in toxicity bioassays in mice and insects.

Results

Analysis of COI sequences from C. chiapanensis showed 94% identity with C. salei, while C. salei exhibited 94-97% identity with sequences from Central and South American conspecifics. The venom from C. chiapanensis exhibited toxic activity against crickets. Venoms from C. chiapanensis and C. salei caused death in Anastrepha obliqua flies. Analysis of venom fractions from C. salei and C. chiapanensis revealed molecular masses of a similar size as some previously reported toxins and neurotoxic components. We determined the amino acid sequences of ChiaTx1 and ChiaTx2, toxins that are reported here for the first time and which showed toxicity against mice and insects.

Conclusion

Our work is the first to report COI-based DNA barcoding sequences from southern Mexican Cupiennius spiders. Compounds with toxic activity were identified in venom from both species.

Infrequent Long-Range Dispersal and Evolution of a Top Terrestrial Arthropod Predator in the Sub-Antarctic

AbstractThe sub-Antarctic terrestrial ecosystems survive on isolated oceanic islands in the path of circumpolar currents and winds that have raged for more than 30 million years and are shaped by climatic cycles that surpass the tolerance limits of many species. Surprisingly little is known about how these ecosystems assembled their native terrestrial fauna and how such processes have changed over time. Here, we demonstrate the patterns and timing of colonization and speciation in the largest and dominant arthropod predators in the eastern sub-Antarctic: spiders of the genus Myro. Our results indicate that this lineage originated from Australia before the Plio-Pleistocenic glacial cycles and underwent an adaptive radiation on the Crozet archipelago, from where one native species colonized multiple remote archipelagos via the Antarctic circumpolar current across thousands of kilometers. The results indicate limited natural connectivity between terrestrial macroinvertebrate faunas in the eastern sub-Antarctic and partial survival of repeated glaciations in the Plio-Pleistocene. Furthermore, our findings highlight that by integrating arthropod taxa from multiple continents, the climatically more stable volcanic Crozet archipelago played a critical role in the evolution and distribution of arthropod life in the sub-Antarctic.

Optimal inventorying and monitoring of taxonomic, phylogenetic and functional diversity

Comparable data is essential to understand biodiversity patterns. While assemblage or community inventorying requires comprehensive sampling, monitoring focuses on as few components as possible to detect changes. Quantifying species, their evolutionary history, and the way they interact requires studying changes in taxonomic (TD), phylogenetic (PD) and functional diversity (FD). Here we propose a method for the optimization of sampling protocols for inventorying and monitoring assemblages or communities across these three diversity dimensions taking sampling costs into account. We used Iberian spiders and Amazonian bats as two case-studies. The optimal combination of methods for inventorying and monitoring required optimizing the accumulation curve of α-diversity and minimizing the difference between sampled and estimated β-diversity (bias), respectively. For Iberian spiders, the optimal combination for TD, PD and FD allowed sampling at least 50% of estimated diversity with 24 person-hours of fieldwork. The optimal combination of six person-hours allowed reaching a bias below 8% for all dimensions. For Amazonian bats, surveying all the 12 sites with mist-nets and 0 or 1 acoustic recorders was the optimal combination for almost all diversity types, resulting in >89% of the diversity and <10% bias with roughly a third of the cost. Only for phylogenetic α-diversity, the best solution was less clear and involved surveying both with mist nets and acoustic recorders. The widespread use of optimized and standardized sampling protocols and regular repetition in time will radically improve global inventory and monitoring of biodiversity. We strongly advocate for the global adoption of sampling protocols for both inventory and monitoring of taxonomic, phylogenetic and functional diversity.

Taxonomic revision of the orb weaving spider genus Plato Coddington, 1986 (Araneae: Theridiosomatidae) with the description of three new species

The genus Plato Coddington, 1986 is revised and now contains twelve Neotropical species. The male of Plato bicolor (Keyserling, 1886) is described for the first time from the state of Amazonas in Brazil. Three new species are described: Plato omnipraesens n. sp. (♂ ♀) from Brazil and Peru, Plato peruana n. sp. (♀) from Peru and Plato hamatus n. sp. (♂ ♀) from Minas Gerais in Brazil. A new diagnosis is proposed for the females of this genus. Morphological structures and genitalic terminology are discussed. Plato species are described, diagnosed, illustrated, and their geographic distribution is mapped.

Insight into the adaptive role of arachnid genome-wide duplication through chromosome-level genome assembly of the Western black widow spider

Although spiders are one of the most diverse groups of arthropods, the genetic architecture of their evolutionary adaptations is largely unknown. Specifically, ancient genome-wide duplication occurring during arachnid evolution ~450 mya resulted in a vast assembly of gene families, yet the extent to which selection has shaped this variation is understudied. To aid in comparative genome sequence analyses, we provide a chromosome-level genome of the Western black widow spider (Latrodectus hesperus)-a focus due to its silk properties, venom applications, and as a model for urban adaptation. We used long-read and Hi-C sequencing data, combined with transcriptomes, to assemble 14 chromosomes in a 1.46 Gb genome, with 38,393 genes annotated, and a BUSCO score of 95.3%. Our analyses identified high repetitive gene content and heterozygosity, consistent with other spider genomes, which has led to challenges in genome characterization. Our comparative evolutionary analyses of eight genomes available for species within the Araneoidea group (orb weavers and their descendants) identified 1,827 single-copy orthologs. Of these, 155 exhibit significant positive selection primarily associated with developmental genes, and with traits linked to sensory perception. These results support the hypothesis that several traits unique to spiders emerged from the adaptive evolution of ohnologs-or retained ancestrally duplicated genes-from ancient genome-wide duplication. These comparative spider genome analyses can serve as a model to understand how positive selection continually shapes ancestral duplications in generating novel traits today within and between diverse taxonomic groups.

Integrative species delimitation and five new species of lynx spiders (Araneae, Oxyopidae) in Taiwan

An accurate assessment of species diversity is a cornerstone of biology and conservation. The lynx spiders (Araneae: Oxyopidae) represent one of the most diverse and widespread cursorial spider groups, however their species richness in Asia is highly underestimated. In this study, we revised species diversity with extensive taxon sampling in Taiwan and explored species boundaries based on morphological traits and genetic data using a two-step approach of molecular species delimitation. Firstly, we employed a single COI dataset and applied two genetic distance-based methods: ABGD and ASAP, and two topology-based methods: GMYC and bPTP. Secondly, we further analyzed the lineages that were not consistently delimited, and incorporated H3 to the dataset for a coalescent-based analysis using BPP. A total of eight morphological species were recognized, including five new species, Hamataliwa cordivulva sp. nov., Hamat. leporauris sp. nov., Tapponia auriola sp. nov., T. parva sp. nov. and T. rarobulbus sp. nov., and three newly recorded species, Hamadruas hieroglyphica (Thorell, 1887), Hamat. foveata Tang & Li, 2012 and Peucetia latikae Tikader, 1970. All eight morphological species exhibited reciprocally monophyletic lineages. The results of molecular-based delimitation analyses suggested a variety of species hypotheses that did not fully correspond to the eight morphological species. We found that Hamat. cordivulva sp. nov. and Hamat. foveata showed shallow genetic differentiation in the COI, but they were unequivocally distinguishable according to their genitalia. In contrast, T. parva sp. nov. represented a deep divergent lineage, while differences of genitalia were not detected. This study highlights the need to comprehensively employ multiple evidence and methods to delineate species boundaries and the values of diagnostic morphological characters for taxonomic studies in lynx spiders.

Spinneret spinning field ontogeny and life history observations in the spider Palpimanus uncatus (Araneae: Palpimanidae)

As in other Palpimanidae, two pairs of posterior spinnerets present in typical Araneomorphae are vestigial in Palpimanus uncatus Kulczyński, 1909, with only the anterior lateral spinneret (ALS) pair prominent. Nevertheless, in late juvenile and adult females, spigots appear in the ancestral posterior spinneret region (PS). Consistent with these spigots serving cylindrical silk glands, females construct substantial egg sacs. While juveniles and adults exhibit a compressed PS, in postembryos it is fully extended. Piriform silk gland (PI) spigots form a linear array on ALSs from the 1st stadium, increasing in number during ontogeny by addition of PIs of the tartipore-accommodated (T-A) subtype (i.e., functional during proecdyses). The number of T-A PIs added from one stadium to the next and locations occupied by their spigots often exhibit a stereotypic pattern, especially consistent in early instars. The number of non-T-A PIs remains constant through ontogeny from the 1st stadium: one per ALS rather than the two per ALS inferred in a few araneoids. The secondary major ampullate silk gland (2° MaA) spigot, primitively uni-shafted among araneomorphs, has become modified into a multi-shafted spigot with extended base, the number of shafts increasing during ontogeny. However, the multiple ducts that connect to the shafts continue to be accommodated during proecdysis by a single enormous tartipore. Sexual dimorphism is present, with late stadium females having greater numbers of T-A PI spigots and 2° MaA spigot shafts. Observations are presented pertaining to feeding behavior, sexual cannibalism (absent), habitat, winter diapause, numbers of molts, and longevity.

Facilitating taxonomy and phylogenetics: An informative and cost-effective protocol integrating long amplicon PCRs and third-generation sequencing

Phylogenetic inference has become a standard technique in integrative taxonomy and systematics, as well as in biogeography and ecology. DNA barcodes are often used for phylogenetic inference, despite being strongly limited due to their low number of informative sites. Also, because current DNA barcodes are based on a fraction of a single, fast-evolving gene, they are highly unsuitable for resolving deeper phylogenetic relationships due to saturation. In recent years, methods that analyse hundreds and thousands of loci at once have improved the resolution of the Tree of Life, but these methods require resources, experience and molecular laboratories that most taxonomists do not have. This paper introduces a PCR-based protocol that produces long amplicons of both slow- and fast-evolving unlinked mitochondrial and nuclear gene regions, which can be sequenced by the affordable and portable ONT MinION platform with low infrastructure or funding requirements. As a proof of concept, we inferred a phylogeny of a sample of 63 spider species from 20 families using our proposed protocol. The results were overall consistent with the results from approaches based on hundreds and thousands of loci, while requiring just a fraction of the cost and labour of such approaches, making our protocol accessible to taxonomists worldwide.

Enigmatic and extravagant genitalia in the spider genus Mastigusa (Araneae, Cybaeidae) - a taxonomic revision

Mastigusa is a genus of small palearctic spiders that has recently been moved to the family Cybaeidae after the first inclusion of the genus in a phylogenetic matrix. Three species are currently recognised: M. arietina , M. lucifuga and M. macrophthalma . The status and delimitation, though, has always been problematic due to inconsistency in the characters used to discriminate between these, leading to great confusion in identity and distribution. We present a detailed morphological redescription of the genus and a taxonomic revision of the included species by the combined use of morphological data and molecular species-delimitation techniques based on the mitochondrial COI gene. The status of the three currently described species has been reevaluated and Mastigusa diversa was revalidated based on material from the Iberian Peninsula, North Africa and the United Kingdom. The distribution of Mastigusa species is updated based on novel taxonomic considerations, and comments on the natural history and ecological differences observed in the species are provided. ZooBank: urn:lsid:zoobank.org:pub:AAD3FAED-440F-4295-B458-455B1D913F81.

Discovering unknown Madagascar biodiversity: integrative taxonomy of raft spiders (Pisauridae: Dolomedes)

Madagascar is a global biodiversity hotspot, but its biodiversity continues to be underestimated and understudied. Of raft spiders, genus Dolomedes Latreille, 1804, literature only reports two species on Madagascar. Our single expedition to humid forests of eastern and northern Madagascar, however, yielded a series of Dolomedes exemplars representing both sexes of five morphospecies. To avoid only using morphological diagnostics, we devised and tested an integrative taxonomic model for Dolomedes based on the unified species concept. The model first determines morphospecies within a morphometrics framework, then tests their validity via species delimitation using COI. It then incorporates habitat preferences, geological barriers, and dispersal related traits to form hypotheses about gene flow limitations. Our results reveal four new Dolomedes species that we describe from both sexes as Dolomedes gregoric sp. nov., D. bedjanic sp. nov., D. hydatostella sp. nov., and D. rotundus sp. nov. The range of D. kalanoro Silva & Griswold, 2013, now also known from both sexes, is expanded to eastern Madagascar. By increasing the known raft spider diversity from one valid species to five, our results merely scratch the surface of the true Dolomedes species diversity on Madagascar. Our integrative taxonomic model provides the framework for future revisions of raft spiders anywhere.

Comparative anatomy of the spinneret musculature in cribellate and ecribellate spiders (Araneae)

Silk production is a prominent characteristic of spiders. The silk is extruded through spigots located on the spinnerets, which are single- to multimembered paired appendages at the end of the abdomen. Most extant spiders have three pairs of spinnerets, and in between either a cribellum (spinning plate) or a colulus (defunct vestigial organ), dividing these spiders into cribellate and ecribellate species. Previous research has shown that cribellate and ecribellate spiders differ not only in the composition of their spinning apparatus but also in the movements of their spinnerets during silk spinning. The objective of this study was to determine whether the differences in spinneret movements are solely due to variations in spinneret shape or whether they are based on differences in muscular anatomy. This was accomplished by analyzing microcomputed tomography scans of the posterior abdomen of each three cribellate and ecribellate species. It was found that the number of muscles did not generally differ between cribellate and ecribellate species, but varied considerably between the species within each of these two groups. Muscle thickness, particularly of the posterior median spinneret, varied slightly between groups, with cribellate spiders exhibiting more robust muscles, possibly to aid in the combing process during cribellar thread production. Interestingly, the vestigial colulus still possesses muscles, that can be homologized with those of the cribellum. This exploration into spinneret anatomy using microcomputed tomography data reveals that despite being small appendages, the spider spinnerets are equipped with a complex musculature that enables them to perform fine-scaled maneuvers to construct different fiber-based materials.

Sensitivity of spiders from different ecosystems to lambda-cyhalothrin: effects of phylogeny and climate

BACKGROUND

In spite of their importance as arthropod predators, spiders have received little attention in the risk assessment of pesticides. In addition, research has mainly focused on a few species commonly found in agricultural habitats. Spiders living in more natural ecosystems may also be exposed to and affected by pesticides, including insecticides. However, their sensitivity and factors driving possible variations in sensitivity between spider taxa are largely unknown. To fill this gap, we quantified the sensitivity of 28 spider species from a wide range of European ecosystems to lambda-cyhalothrin in an acute exposure scenario.

RESULTS

Sensitivity varied among the tested populations by a factor of 30. Strong differences in sensitivity were observed between families, but also between genera within the Lycosidae. Apart from the variation explained by the phylogeny, spiders from boreal and polar climates were more sensitive than spiders from warmer areas. Overall, the median lethal concentration (LC50 ) of 85% of species was below the recommended application rate of lambda-cyhalothrin (75 ng a.i. cm-2 ).

CONCLUSION

Our study underlines the high sensitivity of spiders to lambda-cyhalothrin, which can lead to unintended negative effects on pest suppression in areas treated with this insecticide. The strong differences observed between families and genera indicate that the functional composition of spider communities would change in affected areas. Overall, the variation in spider sensitivity suggests that multispecies investigations should be more widely considered in pesticide risk assessment. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The desert wolf-spider genus Xenoctenus: two endemic species from the Brazilian Caatinga, and a redescription of the type-species, X. unguiculatus (Araneae: Xenoctenidae)

The Caatinga is a nucleus of seasonally dry tropical forest (SDTF) known as a hotspot of diversification and endemism. Despite its importance, this biome is still insufficiently sampled, resulting in extensive knowledge gaps regarding its species richness and composition. In this study we report two species of Xenoctenidae that are endemic to, and widely distributed in the Caatinga. We redescribe and illustrate Odo vittatus (Mello-Leito, 1936), the only xenoctenid species previously known from the Caatinga. We transfer this species to Xenoctenus Mello-Leito,1938, a genus currently known from six species restricted to Argentina, Bolivia, and Colombia. We also newly describe the male of Xenoctenus vittatus comb. nov. and provide new records of this species, which was hitherto known only from the type-locality, throughout the Caatinga and nearby semiarid vegetation formations. We also describe and illustrate a new species, Xenoctenus kaatinga sp. nov., based on males and female specimens collected throughout the Caatinga. Additionally, we propose diagnostic characters for Xenoctenus and redescribe the type-species, X. unguiculatus.

A trade-off in evolution: the adaptive landscape of spiders without venom glands

BACKGROUND

Venom glands play a key role in the predation and defense strategies of almost all spider groups. However, the spider family Uloboridae lacks venom glands and has evolved an adaptive strategy: they excessively wrap their prey directly with spider silk instead of paralyzing it first with toxins. This shift in survival strategy is very fascinating, but the genetic underpinnings behind it are poorly understood.

RESULTS

Spanning multiple spider groups, we conducted multiomics analyses on Octonoba sinensis and described the adaptive evolution of the Uloboridae family at the genome level. We observed the coding genes of myosin and twitchin in muscles are under positive selection, energy metabolism functions are enhanced, and gene families related to tracheal development and tissue mechanical strength are expanded or emerged, all of which are related to the unique anatomical structure and predatory behavior of spiders in the family Uloboridae. In addition, we also scanned the elements that are absent or under relaxed purifying selection, as well as toxin gene homologs in the genomes of 2 species in this family. The results show that the absence of regions and regions under relaxed selection in these spiders' genomes are concentrated in areas related to development and neurosystem. The search for toxin homologs reveals possible gene function shift between toxins and nontoxins and confirms that there are no reliable toxin genes in the genome of this group.

CONCLUSIONS

This study demonstrates the trade-off between different predation strategies in spiders, using either chemical or physical strategy, and provides insights into the possible mechanism underlying this trade-off. Venomless spiders need to mobilize multiple developmental and metabolic pathways related to motor function and limb mechanical strength to cover the decline in adaptability caused by the absence of venom glands.

Advances in the reconstruction of the spider tree of life: A roadmap for spider systematics and comparative studies

In the last decade and a half, advances in genetic sequencing technologies have revolutionized systematics, transforming the field from studying morphological characters or a few genetic markers, to genomic datasets in the phylogenomic era. A plethora of molecular phylogenetic studies on many taxonomic groups have come about, converging on, or refuting prevailing morphology or legacy-marker-based hypotheses about evolutionary affinities. Spider systematics has been no exception to this transformation and the inter-relationships of several groups have now been studied using genomic data. About 51 500 extant spider species have been described, all with a conservative body plan, but innumerable morphological and behavioural peculiarities. Inferring the spider tree of life using morphological data has been a challenging task. Molecular data have corroborated many hypotheses of higher-level relationships, but also resulted in new groups that refute previous hypotheses. In this review, we discuss recent advances in the reconstruction of the spider tree of life and highlight areas where additional effort is needed with potential solutions. We base this review on the most comprehensive spider phylogeny to date, representing 131 of the 132 spider families. To achieve this sampling, we combined six Sanger-based markers with newly generated and publicly available genome-scale datasets. We find that some inferred relationships between major lineages of spiders (such as Austrochiloidea, Palpimanoidea and Synspermiata) are robust across different classes of data. However, several new hypotheses have emerged with different classes of molecular data. We identify and discuss the robust and controversial hypotheses and compile this blueprint to design future studies targeting systematic revisions of these problematic groups. We offer an evolutionary framework to explore comparative questions such as evolution of venoms, silk, webs, morphological traits and reproductive strategies.

The Non-Dereliction in Evolution: Trophic Specialisation Drives Convergence in the Radiation of Red Devil Spiders (Araneae: Dysderidae) in the Canary Islands

Natural selection plays a key role in deterministic evolution, as clearly illustrated by the multiple cases of repeated evolution of ecomorphological characters observed in adaptive radiations. Unlike most spiders, Dysdera species display a high variability of cheliceral morphologies, which has been suggested to reflect different levels of specialization to feed on isopods. In this study, we integrate geometric morphometrics and experimental trials with a fully resolved phylogeny of the highly diverse endemic species from the Canary Islands to 1) quantitatively delimit the different cheliceral morphotypes present in the archipelago, 2) test their association with trophic specialization, as reported for continental species, 3) reconstruct the evolution of these ecomorphs throughout the diversification of the group, 4) test the hypothesis of convergent evolution of the different morphotypes, and 5) examine whether specialization constitutes a case of evolutionary irreversibility in this group. We show the existence of 9 cheliceral morphotypes and uncovered their significance for trophic ecology. Further, we demonstrate that similar ecomorphs evolved multiple times in the archipelago, providing a novel study system to explain how convergent evolution and irreversibility due to specialization may be combined to shape phenotypic diversification in adaptive radiations.

Dynamic evolution of locomotor performance independent of changes in extended phenotype use in spiders

Many animals use self-built structures (extended phenotypes) to enhance body functions, such as thermoregulation, prey capture or defence. Yet, it is unclear whether the evolution of animal constructions supplements or substitutes body functions-with disparate feedbacks on trait evolution. Here, using brown spiders (Araneae: marronoid clade), we explored if the evolutionary loss and gain of silken webs as extended prey capture devices correlates with alterations in traits known to play an important role in predatory strikes-locomotor performance (sprint speed) and leg spination (expression of capture spines on front legs). We found that in this group high locomotor performance, with running speeds of over 100 body lengths per second, evolved repeatedly-both in web-building and cursorial spiders. There was no correlation with running speed, and leg spination only poorly correlated, relative to the use of extended phenotypes, indicating that web use does not reduce selective pressures on body functions involved in prey capture and defence per se. Consequently, extended prey capture devices serve as supplements rather than substitutions to body traits and may only be beneficial in conjunction with certain life-history traits, possibly explaining the rare evolution and repeated loss of trapping strategies in predatory animals.

Revisions of Australian ground-hunting spiders VI: five new stripe-less miturgid genera and 48 new species (Miturgidae: Miturginae)

A group of Australian miturgines that are common in widespread areas of mostly dry landscapes are revised. Five new genera (Miturgopelma, Knotodo, Xistera, Miturgiella and Xeromiturga) and 48 new species are described. Three species presently included in three families are placed in these groups in the Miturgidae: Uliodon ferrugineus (L. Koch, 1873) is transferred from the Zoropsidae to Miturgopelma gen. nov.; likewise, Odo australiensis Hickman, 1944, from Central Australia, is transferred from an otherwise South American genus presently in the family Xenoctenidae to Miturgopelma gen. nov.; and Argoctenus gracilis Hickman, 1950 is transferred to Knotodo gen. nov. Miturgopelma gen. nov. is a very diverse genus found throughout much of drier Australia but not yet in Cape York, Queensland, although one species is taken from Tasmania. Besides Miturgopelma ferruginea (L. Koch, 1873) comb. nov. and Miturgopelma australiensis (Hickman, 1944) comb. nov., the new genus Miturgopelma includes 31 new species: M. alanyeni sp. nov., M. archeri sp. nov. M. baehrae sp. nov., M. bandalup sp. nov., M. biancahilleryae sp. nov., M. bogantungan sp. nov., M. brachychiton sp. nov., M. brevirostra sp. nov., M. bungabiddy sp. nov., M. buckaringa sp. nov., M. calperum sp. nov., M. caitlinae sp. nov., M. couperi sp. nov., M. culgoa sp. nov., M. echidna sp. nov., M. echinoides sp. nov., M. harveyi sp. nov., M. hebronae sp. nov., M. kinchega sp. nov., M. maningrida sp. nov., M. minderoo sp. nov., M. oakleigh sp. nov., M. paruwi sp. nov., M. rangerstaceyae sp. nov., M. rar sp. nov., M. rixi sp. nov., M. seida sp. nov., M. spinisternis sp. nov., M. watarrka sp. nov., M. woz sp. nov., and M. yarmina sp. nov. Knotodo gen. nov., a predominantly western and southern group, includes Knotodo gracilis (Hickman, 1950) comb. nov., and seven new species: K. coolgardie sp. nov., K. eneabba sp. nov., K. narelleae sp. nov., K. shoadi sp. nov., K. muckera sp. nov., K. nullarbor sp. nov., and K. toolinna sp. nov. Xistera gen. nov., another predominantly Western Australian and southern group, includes five new species: Xis. auriphila sp. nov., Xis. barlee sp. nov., Xis. coventryi sp. nov., Xis. jandateae sp. nov., and Xis. serpentine sp. nov. Xeromiturga gen. nov., another predominantly western and southern group, includes four new species: Xer. gumbardo sp. nov., Xer. mardathuna sp. nov., Xer. bidgemia sp. nov., and Xer. pilbara sp. nov. A widespread, monotypic eastern Australian genus, Miturgiella vulgaris gen. et sp. nov., is also described. Zoroides Berland, 1924, presently in Miturgidae, is considered a junior synonym of the phrurolithid Dorymetaecus Rainbow, 1920 syn. nov., thus making Dorymetaecus dalmasi (Berland 1924) comb. nov. Miturga whistleri Simon, 1909 and Miturga splendens Hickman, 1930 are both placed in Mituliodon tarantulinus syn. nov..

Widow spiders alter web architecture and attractiveness in response to same-sex competition for prey and mates, and predation risk

Female-female competition in animals has rarely been studied. Responses of females that compete context-dependently for mates and prey, and seek safety from predators, are ideally studied with web-building spiders. Cobwebs possess unique sections for prey capture and safety, which can be quantified. We worked with Steaoda grossa females because their pheromone is known, and adjustments in response to mate competition could be measured. Females exposed to synthetic sex pheromone adjusted their webs, indicating a perception of intra-sexual competition via their sex pheromone. When females sequentially built their webs in settings of low and high intra-sexual competition, they adjusted their webs to increase prey capture and lower predation risk. In settings with strong mate competition, females deposited more contact pheromone components on their webs and accelerated their breakdown to mate-attractant pheromone components, essentially increasing their webs' attractiveness. We show that females respond to sexual, social and natural selection pressures originating from intra-sexual competition.

Purified Native Protein Extracted from the Venom of Agelena orientalis Attenuates Memory Defects in the Rat Model of Glutamate-Induced Excitotoxicity

Spider venom contains various peptides and proteins, which can be used for pharmacological applications. Finding novel therapeutic strategies against neurodegenerative diseases with the use of purified peptides and proteins, extracted from spiders can be greatly precious. Neurodegenerative diseases are rapidly developing and expanding all over the world. Excitotoxicity is a frequent condition amongst neuro-degenerative disorders. This harmful process is usually induced through hyper-activation of N-Methyl-D-Aspartate (NMDA) receptor, and P/Q-type voltage-gated calcium channels (VGCCs). The omega-agatoxin-Aa4b is a selective and strong VGCCblocker. This study aimed to investigate the effects of this blocker on the NMDA-induced memory and learning defect in rats. For this purpose, nineteen spiders of the funnel-weaver Agelena orientalis species were collected. The extracted venom was lyophilized andpurified through gel-filtration chromatography, and capillary electrophoresis techniques. Subsequently, mass spectrometry (HPLC-ESI-MS) was used for identification of this bio-active small protein. Afterward, the effect of the omega-agatoxin-Aa4b (2 μg, intra-cornu ammonis-3 of the hippocampus) on the NMDA-induced learning and memory deficits in rats was evaluated. Learning and memory performances were evaluated by the use of passive avoidance test. For synaptic quantification and memory function the amount of calcium/calmodulin-dependent protein kinase ІІ (CaCdPKІІ) gene expression was measured using the Real-time PCR technique. To compare the experimental groups, hematoxylin and eosin (H&E) staining of hippocampus tissues was performed. Our results rendered that the omega-Agatoxin-Aa4b treatment can ameliorate and reverse the learning and memory impairment caused by NMDA-induced excitotoxicity in rat hippocampus.

Taxonomic revision of the soldier spider genus Falconina Brignoli, 1985 (Araneae: Corinnidae: Corinninae)

The genus Falconina Brignoli, 1985 is revised and redescribed, including ten species. New records and documentation of morphological variation in F. gracilis (Keyserling, 1891) are presented; it and the type species, F. melloi (Schenkel, 1953), are rediagnosed. Falconina albomaculosa (Schmidt, 1971) is redescribed based on the female holotype and additional material from Ecuador, with the male being described for the first time. Falconina crassipalpis (Chickering, 1937) is redescribed based on the types and additional material from Barro Colorado, Panama. Six new species are described, diagnosed, and illustrated: F. iza sp. nov. ( from Rio Grande do Sul, Brazil); F. taita sp. nov. ( from Chapare and from Sapecho, Bolivia); F. catirina sp. nov. ( from Piau, Brazil); F. adriki sp. nov. ( and from Rio de Janeiro, Brazil); F. andresi sp. nov. ( from Meta, Colombia); and F. brignolii sp. nov. ( from Sucre, Venezuela). Additionally, distribution maps and an identification key to all of the known species of Falconina are provided.

Appendage abnormalities in spiders induced by an alternating temperature protocol in the context of recent advances in molecular spider embryology

In the literature there are numerous reports of developmental deformities in arthropods collected in their natural habitat. Since such teratogenically affected individuals are found purely by chance, the causes of their defects are unknown. Numerous potential physical, mechanical, chemical, and biological teratogens have been considered and tested in the laboratory. Thermal shocks, frequently used in teratological research on the spider Eratigena atrica, have led to deformities on both the prosoma and the opisthosoma. In the 2020/2021 breeding season, by applying alternating temperatures (14 °C and 32 °C, changed every 12 h) for the first 10 days of embryonic development, we obtained 212 postembryos (out of 3,007) with the following anomalies: oligomely, heterosymely, bicephaly, schistomely, symely, polymely, complex anomalies, and others. From these we selected six spiders with defects on the prosoma and two with short appendages on the pedicel for further consideration. The latter cases seem particularly interesting because appendages do not normally develop on this body part, viewed as the first segment of the opisthosoma, and appear to represent examples of atavism. In view of the ongoing development of molecular techniques and recent research on developmental mechanisms in spiders, we believe the observed phenotypes may result, at least in part, from the erroneous suppression or expression of segmentation or appendage patterning genes. We consider "knockdown" experiments described in the literature as a means for generating hypotheses about the sources of temperature-induced body abnormalities in E. atrica.

A new species of Jacaena Thorell, 1897 (Araneae: Liocranidae) from Guiyang, southwestern China

A new species belonging to the liocranid genus Jacaena Thorell, 1897, J. guiyang sp. nov., is described from southwestern China. A detailed description, diagnosis, photographs, and distribution map of the new species are given. DNA barcodes of the species were obtained and confirmed matching of the sexes, and are available for future use.

Lampshade web spider Ectatosticta davidi chromosome-level genome assembly provides evidence for its phylogenetic position

The spider of Ectatosticta davidi, belonging to the lamp-shade web spider family, Hypochilidae, which is closely related to Hypochilidae and Filistatidae and recovered as sister of the rest Araneomorphs spiders. Here we show the final assembled genome of E. davidi with 2.16 Gb in 15 chromosomes. Then we confirm the evolutionary position of Hypochilidae. Moreover, we find that the GMC gene family exhibit high conservation throughout the evolution of true spiders. We also find that the MaSp genes of E. davidi may represent an early stage of MaSp and MiSp genes in other true spiders, while CrSp shares a common origin with AgSp and PySp but differ from MaSp. Altogether, this study contributes to addressing the limited availability of genomic sequences from Hypochilidae spiders, and provides a valuable resource for investigating the genomic evolution of spiders.

Complete mitochondrial genome of a golden orb-web spider Trichonephila clavata (Chelicerata, Arachnida) from South Korea

The mitochondrial genome of a golden orb-web spider Trichonephila clavata (L. Koch, 1878) from South Korea is determined and characterized in detail, which is the second mitochondrial genome reported from this species: the first was published from the Chinese sample by Pan et al. (2016). It was 14,436 bp in length being composed of 13 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and one control region (CR). It has a base composition of 35.99% for 'A,' 14.88% for 'G,' 9.09% for 'C,' and 40.04% for 'T.' Comparing the South Korean and Chinese mitochondrial genomes, we observed 8% nucleotide sequence differences between their CRs, caused by the different numbers and sorts of possessed tandem repeats, suggesting a promising molecular marker to distinguish South Korean individuals from Chinese ones. The phylogenetic trees using the maximum likelihood (ML) method were reconstructed with nucleotides (without 3rd codon position) and amino acids from 13 PCGs, respectively, which consistently confirmed that T. clavata (Subfamily Nephilinae) from South Korea and China are clustered together, distinctly separated from the other subfamily Araneinae in the monophyletic family Araneidae.

Two species of hackled-orb web spider genus Hyptiotes (Araneae, Uloboridae) from Guangxi, China

Two species of the genus Hyptiotes Walckenaer 1837 are described from Guangxi Zhuang Autonomous Region, China, including a new species, Hyptiotes nonggang n. sp. (♂♀), and a known species, Hyptiotes paradoxus (C. L. Koch, 1834) (♂♀) which is the type species. Detailed descriptions and illustrations of the two species are provide, and a map of collecting localities of them in China is also provided.

Taxonomic review of the Andean crab spiders genus Coenypha Simon, 1895 (Thomisidae: Stephanopinae)

The genus Coenypha Simon, 1895 is composed of species distributed on the Southern Andean Region and Patagonia, and presents remarkable somatic morphologies, such as the flattened habitus, enlarged femora I, and a wide opisthosoma. Molecular and morphology-based phylogenies have revealed the close relationship of this genus with sympatric species previously assigned to Stephanopis O. Pickard-Cambridge, 1869. Our recent cladistic analysis extended such preliminary results in recovering numerous morphological characters as synapomorphies of a well-supported clade, thus justifying the transfer of all species of 'Andean Stephanopis' to Coenypha. In the present work, we provide a taxonomic review of these species, update their diagnoses, descriptions and illustrate them through detailed photographs. New distribution records are presented, the male of C. antennata (Tullgren, 1902) is described for the first time, and two new species are described based on both sexes (Coenypha trapezium sp. nov. and Coenypha foliacea sp. nov.). Stephanopis exigua (Nicolet, 1849) is considered a nomen dubium. Stephanopis verrucosa (Nicolet, 1849), Thomisus spectrum Nicolet, 1849, and T. pubescens Nicolet, 1849 are synonymized with Coenypha nodosa (Nicolet, 1849). The synonymy of Thomisus nicoleti Roewer, 1951 (a replaced name for T. cinereus Nicolet, 1849 due to a homonymy) with Misumenops temibilis (Holmberg, 1876) is rejected, and considered together with Stephanopis spissa (Nicolet, 1849), Thomisus variabilis Nicolet, 1849 and Stephanopis maulliniana Mello-Leitão, 1951, synonyms of Coenypha ditissima (Nicolet, 1849); Stephanopis badia Keyserling, 1880 is transferred to Sidymella Strand, 1942.

Phylogenomics illuminates the evolution of orb webs, respiratory systems and the biogeographic history of the world's smallest orb-weaving spiders (Araneae, Araneoidea, Symphytognathoids)

The miniature orb weaving spiders (symphytognathoids) are a group of small spiders (< 2 mm), including the smallest adult spider Patu digua (0.37 mm in body length), that have been classified into five families. The species of one of its constituent lineages, the family Anapidae, build a remarkable diversity of webs (ranging from orbs to sheet webs and irregular tangles) and even include a webless kleptoparasitic species. Anapids are also exceptional because of the extraordinary diversity of their respiratory systems. The phylogenetic relationships of symphytognathoid families have been recalcitrant with different classes of data, such as, monophyletic with morphology and its concatenation with Sanger-based six markers, paraphyletic (including a paraphyletic Anapidae) with solely Sanger-based six markers, and polyphyletic with transcriptomes. In this study, we capitalized on a large taxonomic sampling of symphytognathoids, focusing on Anapidae, and using de novo sequenced ultraconserved elements (UCEs) combined with UCEs recovered from available transcriptomes and genomes. We evaluated the conflicting relationships using a variety of support metrics and topology tests. We found support for the phylogenetic hypothesis proposed using morphology to obtain the "symphytognathoids'' clade, Anterior Tracheal System (ANTS) Clade and monophyly of the family Anapidae. Anapidae can be divided into three major lineages, the Vichitra Clade (including Teutoniella, Holarchaea, Sofanapis and Acrobleps), the subfamily Micropholcommatinae and the Orb-weaving anapids (Owa) Clade. Biogeographic analyses reconstructed a hypothesis of multiple long-distance transoceanic dispersal events, potentially influenced by the Antarctic Circumpolar Current and West Wind Drift. In symphytognathoids, the ancestral anterior tracheal system transformed to book lungs four times and reduced book lungs five times. The posterior tracheal system was lost six times. The orb web structure was lost four times independently and transformed into sheet web once.

Dispersal ability and niche breadth influence interspecific variation in spider abundance and occupancy

The relationship between species local abundance and their regional distribution (occupancy) is one of the most extensively recognized and investigated patterns in ecology. While exceptions exist, the generally held model is that locally abundant species also tend to be more widespread geographically. However, there is only a limited understanding of both the mechanisms driving this relationship, and their scale dependency. Here we use occupancy and abundance data for 123 species of spider from across the Canary Islands to understand how both dispersal ability and niche breadth might mediate variation among species for local abundance and occupancy. We test the predictions that (i) dispersal ability explains variation among species for both abundance and occupancy, and (ii) species with a higher degree of habitat specialization, reflecting more limited niche breadth, will have both higher occupancy and abundance. We find no evidence within habitat patches for an effect of dispersal ability on either local abundance or site occupancy, while across all patches species with higher dispersal ability tend to occupy more sites. Species largely restricted to laurel forests have higher abundance than species with broader niche breadth, but similar occupancy. The study revealed that dispersal ability and niche breadth were significant predictors of the abundance-occupancy relationship, highlighting the importance of both factors for understanding patterns of abundance and occupancy among spider species.

Evolution and comparative morphology of raptorial feet in spiders

Spiders are among the most diverse animals, which developed different morphological and behavioral traits for capturing prey. We studied the anatomy and functionality of the rare and apomorphic raptorial spider feet using 3D reconstruction modeling, among other imaging techniques. The evolutionary reconstruction of the raptorial feet (tarsus plus pretarsus) features using a composite tree of spiders, indicating that similar traits emerged three times independently in Trogloraptoridae, Gradungulinae, and Doryonychus raptor (Tetragnathidae). The characteristics defining the raptorial feet are an interlocked complex merging of the base of the elongated prolateral claw with the pretarsal sclerotized ring, with the former clasping against the tarsus. Raptorial feet even flex over robust raptorial macrosetae forming a reduced tarsal version of a catching basket to encase prey during hunting. Our results show that Celaeniini (Araneidae) and Heterogriffus berlandi (Thomisidae), taxa previously compared with raptorial spiders, lack the raptorial feet key characteristics and the tarsal-catching basket. We make predictions about the possible behavior of the abovementioned taxa that will need to be tested by observing living specimens. We conclude that multiple morphological tarsal and pretarsal micro-structures define the raptorial foot functional unit and recommend a comprehensive evaluation before assigning this configuration to any spider taxa.

Assessing the impact of fire on spiders through a global comparative analysis

In many regions fire regimes are changing due to anthropogenic factors. Understanding the responses of species to fire can help to develop predictive models and inform fire management decisions. Spiders are a diverse and ubiquitous group and can offer important insights into the impacts of fire on invertebrates and whether these depend on environmental factors, phylogenetic history or functional traits. We conducted phylogenetic comparative analyses of data from studies investigating the impacts of fire on spiders. We investigated whether fire affects spider abundance or presence and whether ecologically relevant traits or site-specific factors influence species' responses to fire. Although difficult to make broad generalizations about the impacts of fire due to variation in site- and fire-specific factors, we find evidence that short fire intervals may be a threat to some spiders, and that fire affects abundance and species compositions in forests relative to other vegetation types. Orb and sheet web weavers were also more likely to be absent after fire than ambush hunters, ground hunters and other hunters suggesting functional traits may affect responses. Finally, we show that analyses of published data can be used to detect broad-scale patterns and provide an alternative to traditional meta-analytical approaches.

The phylogenetic structure and coalescent species delimitation of an endemic trapdoor spider genus, Stasimopus (Araneae, Mygalomorphae, Stasimopidae) in the Karoo region of South Africa

The Karoo region of South Africa is a unique and sensitive ecosystem which is facing pressure for development due to economic incentives such as mining, farming and shale gas exploration. The species diversity of many taxa in the area is largely unknown. A phylogenetic analysis of the cork-lid trapdoor spider genus, Stasimopus (Stasimopidae) was undertaken in order to gain insight into the relationships between the species that may be present in the area. The species within Stasimopus are challenging to identify and define using traditional morphological methods due to a high degree of morphological conservatism within the genus. For this reason, multiple coalescent based species delimitation methods were used to attempt to determine the species present for Stasimopus in the region which was tested against the morphological identifications and genetic clades (based on CO1, 16S and EF-1ɣ). We tested single-locus methods Automatic Barcode Gap Discovery (ABGD), Bayesian implementation of Poisson Tree Processes (bPTP) and General Mixed Yule- Coalescent (GMYC), as well as multi-locus Brownie. The phylogenetic analysis of Stasimopus in the Karoo showed that there is a high degree of genetic diversity within the genus. The species delimitation results proved unfruitful for the genus, as they appear to delimit population structure rather than species for most methods. Alternative methods should be investigated to aid in the identification of the species in order truly understand the species diversity of the genus.

Disentangling the Taxonomy, Systematics, and Life History of the Spider-Parasitic Fungus Gibellula (Cordycipitaceae, Hypocreales)

Gibellula (Cordycipitaceae, Hypocreales) is frequently observed growing on spiders, but little is known about their host range. One of the greatest challenges in describing these interactions is identifying the host, since the fungus often rapidly consumes the parasitised spiders and destroys important diagnostic taxonomic traits. Additionally, the global diversity of Gibellula remains unclear, as does the natural history and phylogenetic relationships of most of the species. Herein, we performed an extensive investigation on the species of Gibellula, reconstructed the most complete molecular phylogeny of the genus in the context of Cordycipitaceae, and performed a systematic review in order to provide the foundations towards a better understanding of the genus. Therefore, we have performed an integrative study to investigate the life history of the genus and to disentangle the questionable number of valid species proposed over time. We provided novel molecular data for published species that had not been sequenced before, such as G. mirabilis and G. mainsii, and evaluated all the original and modern morphological descriptions. In addition, we presented its global known distribution and compiled all available molecular data. We suggested a set of terms and morphological traits that should be considered in future descriptions of the genus and that a total of 31 species should be considered as accepted.

A novel probe set for the phylogenomics and evolution of RTA spiders

Spiders are important models for evolutionary studies of web building, sexual selection and adaptive radiation. The recent development of probes for UCE (ultra-conserved element)-based phylogenomic studies has shed light on the phylogeny and evolution of spiders. However, the two available UCE probe sets for spider phylogenomics (Spider and Arachnida probe sets) have relatively low capture efficiency within spiders, and are not optimized for the retrolateral tibial apophysis (RTA) clade, a hyperdiverse lineage that is key to understanding the evolution and diversification of spiders. In this study, we sequenced 15 genomes of species in the RTA clade, and using eight reference genomes, we developed a new UCE probe set (41 845 probes targeting 3802 loci, labelled as the RTA probe set). The performance of the RTA probes in resolving the phylogeny of the RTA clade was compared with the Spider and Arachnida probes through an in-silico test on 19 genomes. We also tested the new probe set empirically on 28 spider species of major spider lineages. The results showed that the RTA probes recovered twice and four times as many loci as the other two probe sets, and the phylogeny from the RTA UCEs provided higher support for certain relationships. This newly developed UCE probe set shows higher capture efficiency empirically and is particularly advantageous for phylogenomic and evolutionary studies of RTA clade and jumping spiders.