A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala

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  A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala Abstract  A new species of the spider genus Euagrus Ausserer, 1875 from temperate pine-oak forests in the states of Tlaxcala and Hidalgo, Mexico is described: E. pulque sp. nov. The description of the new species is based on male and female adult specimens. Additionally, Euagrus gus Coyle, 1988 is recorded for the very first time in the state of Tlaxcala. These species have sympatric distributions in La Malinche National Park, Tlaxcala. With this description, the diversity of the genus increases to 23 species, with Mexico harboring the highest diversity with 17 described species.  Valdez-Mondragón, A., Salinas-Velasco, H. V. & Bueno-Villegas, J. (2026). A new species of the mygalomorph spider genus Euagrus Ausserer (Araneae: Euagridae) from central Mexico and new records of E. gus Coyle from Tlaxcala. Zootaxa 5810 (...

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

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

ABSTRACT

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.

Zhang, R., Xiang, N., Gao, X., Zhang, G., Lu, T., & Yuan, T. (2025). Molecular Phylogenetic Relationships Based on Mitogenomes of Spider: Insights Into Evolution and Adaptation to Extreme Environments. Ecology and Evolution, 15(1), e70774. https://doi.org/10.1002/ece3.70774