Notes on the identity of the orb-weaver spider Araneus nox Simon, 1877 (Araneae: Araneidae) from India, including its transfer to Eriovixia Archer, 1951 and one new synonymy

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  Notes on the identity of the orb-weaver spider Araneus nox Simon, 1877 (Araneae: Araneidae) from India, including its transfer to Eriovixia Archer, 1951 and one new synonymy The orb-weaver genus Araneus Clerck, 1757 has historically served as a heterogeneous assemblage for numerous araneid spiders lacking clear generic placement, and several Asian species formerly assigned to Araneus have subsequently been transferred to more narrowly defined genera. One species that still needs further investigation on its true identity is Araneus nox (Simon, 1877), originally described as Epeira nox Simon, 1877 from Basilan Island, Philippines, and later transferred to Araneus by Simon (1905). In the same year as the description of Epeira nox, Thorell (1877) described Epeira pilula from the Moluccas (Indonesia), which was subsequently synonymised under Epeira nox by Simon (1880). Despite its broad Oriental distribution, the taxonomic identity and generic placement of A. nox have remained insuff...

Complete Mitochondrial Genome Sequencing of Brachypelma albiceps and Comparative Codon Usage Bias Analysis Across Seven Mygalomorphae Species

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Complete Mitochondrial Genome Sequencing of Brachypelma albiceps and Comparative Codon Usage Bias Analysis Across Seven Mygalomorphae Species

Abstract

Tarantulas (family Theraphosidae) are ecologically significant invertebrate predators in terrestrial ecosystems, but many species face threats from habitat fragmentation and unsustainable collection for the international pet trade. Brachypelma albiceps, a CITES Appendix II-listed species, lacks comprehensive mitochondrial genome characterization, limiting phylogenetic and evolutionary studies. Here, we report a complete mitochondrial genome sequence for B. albiceps (13,856 bp; GC content 32.84%) and provide detailed annotation. The genome exhibits typical metazoan mitochondrial organization, containing 13 protein-coding genes (PCGs), 22 tRNAs, and 2 rRNAs, with an AT-rich nucleotide composition (67.16%) characteristic of arthropod mitochondria. Comparative analyses of B. albiceps and six other Mygalomorphae species revealed strong biases toward A/T-ending codons and avoidance of G/C-ending codons. ENC–GC3s, neutrality, and PR2 analyses consistently indicate that natural selection plays a dominant role in shaping synonymous codon usage, with mutation pressure also contributing. Phylogenetic reconstruction based on 10 high-quality mitochondrial protein-coding genes from 23 spider species confirmed the placement of B. albiceps within the family Theraphosidae and its close phylogenetic relationship to Cyriopagopus species. These results provide valuable genomic resources for the Theraphosidae systematics, enhance our understanding of codon bias evolution, and provide critical DNA barcode data for forensic identification of CITES-regulated specimens in the illegal wildlife trade.

Zhan, Q., Tang, Y., Zhao, Y., Hou, S., Huang, Y., Zhao, X., Chen, Y., & Xue, X. (2026). Complete Mitochondrial Genome Sequencing of Brachypelma albiceps and Comparative Codon Usage Bias Analysis Across Seven Mygalomorphae Species. Biology. https://doi.org/10.3390/biology15010016