A morphometric approach to the comparative morphology of aedeagi shapes in net-winged beetles: A case study on the Macrolycus dotatus species group (Coleoptera: Lycidae)

Insect male genitalia show an evolutionarily variable morphology that is valuable for both species identification and phylogenetic analyses. However, we often encounter some difficulties when conducting relevant studies due to only quantitative variations exhibited in male genitalia. In this study, based on the taxonomy of the Macrolycus dotatus species group (a total of seven species, including three new species described here), we analyzed the male genitalia shapes by GM and then constructed the phenotypic relationships by UPGMA, NJ and MP analyses. The results demonstrated that the species could be well delineated by the shape of male genitalia, and the produced phenograms frequently recovered phenotypic similarity between the coupled species, including M. atronotatimimus sp. nov. + M. huoditangensis sp. nov. and M. aemulus + M. dotatus, which is useful for making comparisons in species descriptions. Meanwhile, the MP analysis of male genitalia shape using two landmark configurations is considered reliable in inferring the phylogenetic relationship among species in terms of the consistency between its topologies and the molecular phylogeny. This study sheds new light on improving the morphological taxonomy of insects in lower grades while fully utilizing the taxonomic value of male genitalia in a phylogenetic context.