The spider ofEctatosticta 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 ofE. davidiwith 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 ofE. davidimay 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.

Spiders have primarily adapted to terrestrial life, yet a number of species have made evolutionary transitions to marine and freshwater environments. While its physiological and behavioral adaptations have been characterized, the genetic basis of semi-aquatic and aquatic adaptation in spiders remains poorly understood. Here, we provide a high-quality, chromosome-level genome assembly for the aquatic spider Argyroneta aquatica , alongside a reference transcriptome for the semi-aquatic spider Desis martensi . We performed comparative genomes analyses of 22 spider species, including a unique aquatic spider, two semi-aquatic spiders and 19 terrestrial spider species, with a focus on those in the marronoid clade. By integrating morphological, phylogenomic, comparative genomic, transcriptomic, and metabolomic analyses, we explored the genomic adaptations of aquatic and semi-aquatic spiders. Phylogenomic analysis suggests that aquatic and semi-aquatic spiders have independently evolved from their terrestrial ancestors and represent divergent evolutionary routes We found hundreds of genes tend to experience relaxed selection, positive selection, and evidence of horizontal gene transfer (HGT) associated with the transition to aquatic and semi-aquatic life in spiders. These genes are associated with respiratory, osmoregulatory, fat metabolism and digestion, hypoxia, and thermal functions, putatively facilitate the adaptations to diverse underwater life. Altogether, our findings highlight the divergent evolutionary mechanisms enabling spiders to thrive in diverse aquatic environments, providing insights into the genomic basis of adaptations to semi-aquatic and aquatic habitats.

Spiders are largely terrestrial, but some lineages have independently adapted to marine and freshwater habitats. Although physiological and behavioral traits supporting these evolutionary transitions have been characterized, the genomic basis of adaptation to aquatic and semi-aquatic habitats in spiders remains unclear. Here, we report a chromosome-level genome assembly for the aquatic spider Argyroneta aquatica. Comparative analysis of 22 spider species supports 2 independent transitions in semi-aquatic (∼56 Mya) and aquatic (∼44 Mya) lineages. The aquatic spider shows distinct respiratory morphology compared with terrestrial spiders, including anterior spiracles and denser tracheoles. Molecular evolution analyses identified lineage-specific shifts in selective constraint or evidence of positive selection linked to trachea development (eg Wnt-1, Catenin beta, TMEM234, Arp3), hypoxia response (eg Uqcrfs1, COX5B, SLC2A3), lipid metabolism (eg Pnliprp2, ND-ACP), and osmoregulation. In the semi-aquatic spiders (Desis spp.), we detected strengthened purifying selection or positive selection on genes involved in respiratory/energy metabolism (eg SdhD, SLC2A3) and ion transporters (eg. Slc24a5). Comparative results further indicate that the A. aquatica genome may harbor bacterial-origin genes homologous to ABC transporters (39 genes) and acyl-CoA dehydrogenases (ACADs; 21 genes), which may support metabolic or transport functions in the aquatic lineage. Transcriptomic and metabolomic profiling of A. aquatica under hypoxic challenge revealed metabolic reprogramming, including shifts in glycolytic and TCA intermediates and upregulation of genes that promote fatty-acid β-oxidation (eg Slc13a5, AACS), consistent with extended anoxia tolerance (>48 h). Overall, this work provides genomic resources and highlights genomic signatures associated with semi-aquatic and aquatic adaptation in spiders.

Based on biological, morphological, distributional and genomic data, it is concluded that the malvid-associated Baris albosparsa (Faust), Malvaevora timida (Rossi) and Squamobaris aurea Pajni, Kohli & Kumar are monophyletic and distinct from Baris Germar. Squamobaris Pajni, Kohli & Kumar is synonymized with Malvaevora Zaslavskij (new synonymy). Baris albosparsa and S. aurea are transferred to Malvaevora (new combinations). Baris timida polita Reitter, B. subtilina Reitter, Baridius landgrebii Hochhuth and Baridius striatopunctatus Gistel are synonymized with M. timida and Baris striatopunctata Reitter is synonymized with Melanobaris carbonaria (Boheman) (new synonymies). Lectotypes are designated for B. timida polita and B. landgrebii. Baris striolala Aurivillius is recorded from China for the first time.

Background: The phylogenetic resolution within the Gloydius halys-intermedius Complex remains debatable due to the following reasons: loci selection in previous studies varied between authors; limited dataset (1−5 mitochondrial or nuclear gene fragments); lack of sampling density; and nodal supports at specific nodes remain weak, specifically within Gloydius cognatus, G. halys, and G. stejnegeri. Objectives: To revise the taxonomic and phylogenetic relationships within the G. halys-intermedius Complex, we reconstructed the molecular phylogeny and performed species delimitation based on the complete mitochondrial genomes. Methods: In this study, twelve nomenclatural groups of Gloydius species were involved in the computation of Bayesian phylogenomic inference, five of the twelve nomenclature groups were newly sequenced, while the rest were acquired from the National Center for Biotechnology Information (NCBI). The Bayesian phylogenomic inference was constructed based on 13 mitochondrial protein-coding genes. Species delimitation was performed by two distance-based methods (ABGD and ASAP) and two tree-based methods (GMYC and bPTP). Results: This research resolved the systematic relationship within the G. intermedius Complex with the support of mitogenome-based phylogenomics, while indicating cryptic diversity within the Gloydius halys-intermedius Complex: G. intermedius samples from South Korea show as paraphyletic to the cluster of the samples from northeastern China. Species delimitation results based on four models resemble each other, supporting Gloydius caucasicus, G. cognatus, G. halys, and G. stejnegeri, each representing full species. The species delimitation results of this research also resemble the nomenclatural species based on previous morphometrical results. This research indicates that species delimitation efforts based on the phylogenomic approach would likely resolve complex evolutionary relationships.

Evolutionary biology faces the important challenge of determining how to interpret the relationship between selection pressures and evolutionary radiation of species. The different biodiversity indicators highlight the disparate nature of biodiversity investigations. However, the influence of ecological factors and the specificity of taxonomic phylogeny have led to controversy over the correlation between these indicators. By combining quantitative morphology and statistical methods, here we analyze the biodiversity under the influences of phylogenetic relation factors represented by higher categories. A total of 8508 species of beetles from 1247 genera, 34 subfamilies, and 10 families of the Scarabaeoidea were selected as a test group; 70% of the family-level samples and 60% of the subfamily-level samples were selected at a proportion of 10–30% of the global described species. The taxonomic categories of family and subfamily were selected for phylogenetic representation, and the analysis of geometric morphometrics on the pronotum and elytron, which represent the major aspect of the morphology in dorsal view, was conducted. Through principal component analysis and Spearman correlation coefficient analysis, it was found that: the morphological diversity of the pronotum is higher in most groups of family/subfamily category than in the elytron; the correlation between the morphological diversity and species richness of the pronotum in the superfamily Scarabaeoidea is higher than that of the elytron; correlations between morphological diversity of the pronotum and taxa richness among sub-/families were always found to be consistent, and it was higher than it in the elytron test. This study compares the correlation between the diversity of different characters and the richness of taxa to interpret the phylogenetic impacts of biodiversity and sheds light on a fresh perspective for detailed studies of the selection pressures and formation mechanisms regulating the rise and fall of species.