Phylogeny of euophryine jumping spiders from ultra-conserved elements, with evidence on the intersexual coevolution of genitalia (Araneae: Salticidae: Euophryini)

Knowledge of phylogeny is required to understand the evolution of highly diverse groups such as the euophryine jumping spiders, a lineage showing high species and morphological diversity. In this study, we applied a phylogenomic approach using ultra-conserved elements (UCE) obtained from 145 taxa to infer the phylogeny of euophryine jumping spiders. The results provide a well-supported phylogenetic framework for Euophryini, especially for the deeper relationships, in which the monophyly of Euophryini, as well as most clades corresponding to a genus or a group of closely related genera, are strongly supported. Additionally, the evolutionary patterns of male embolus length and female copulatory duct length of 117 euophryine species were investigated through ancestral character state reconstruction and phylogenetically independent contrast analyses using the UCE phylogenetic framework. The results suggest strongly that the evolution of the lengths of male embolus and female copulatory duct in Euophryini is positively correlated. The common ancestor of Euophryini likely had relatively short embolus and copulatory duct, followed by repeated lengthening or shortening of both structures in different lineages. Possible mechanisms that may have caused this intersexual coevolution pattern in Euophryini are discussed. This study advances our understandings of the phylogeny, systematics and genitalic evolution of euophryines, providing a solid foundation for future studies on the diversification and evolution of this jumping spider group.