Testing the Limits of Morphology: A Comprehensive Morphometric Study of the Sister Lineages Lasiocyano Galleti-Lima, Hamilton, Borges and Guadanucci, 2023 and Lasiodora C. L. Koch, 1850 (Theraphosidae, Mygalomorphae)

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  Testing the Limits of Morphology: A Comprehensive Morphometric Study of the Sister Lineages Lasiocyano Galleti-Lima, Hamilton, Borges and Guadanucci, 2023 and Lasiodora C. L. Koch, 1850 (Theraphosidae, Mygalomorphae) ABSTRACT Morphological conservatism and homoplasy pose significant challenges for the systematics of mygalomorph spiders, limiting the number of reliable morphological characters available for species identification, particularly in Theraphosidae. Closely related taxa frequently display high phenotypic similarity, which limits the resolution of morphology-based approaches. In this study, we conducted the most extensive morphometric analysis to date within Theraphosidae, with the objective of explicitly testing how much morphological information is retained within the  Lasiocyano sazimai  and  Lasiodora  lineage. We applied a morphometric framework combining linear morphometry and geometric morphometry, including multivariate statistics, discrimina...

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

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


Abstract



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.

Li Z, Zhang F. 2025. Comparative mitogenomics of Cheiracanthium species (Araneae: Cheiracanthiidae) with phylogenetic implication and evolutionary insights. PeerJ 13:e18314 https://doi.org/10.7717/peerj.18314