Molecular Techniques and Ecological Data for Taxonomically Difficult Groups: A Case Study of a Morphologically Variable New Species in the Genus Chrysobothris (Coleoptera: Buprestidae)

Morphological characters of beetles can differ greatly, even within a single species, necessitating the integration of molecular techniques and ecological data for accurate taxonomical delineation, particularly within taxonomically challenging groups. <i>Chrysobothris</i>, a world-distributed genus of considerable size with a homonymy rate exceeding 1/5, frequently presents ambiguities in species boundaries. In this research, a series of <i>Chrysobothris</i> specimens collected from southern China were segregated into four sharply contrasting external morphotypes. A taxonomic ambiguity was initially posed: whether they represented several species, intraspecific polymorphism within a single species, or geographic/intraspecific variants of the similar species <i>Chrysobothris violacea</i> Kerremans, 1892. COI barcoding and phylogenetic analyses supported the conspecificity of these morphotypes and confirmed their distinction from <i>C. violacea</i> at the species level. Based on integrated evidence, we describe these specimens as <i>Chrysobothris borealina</i> Huang, Wu & Song, sp. nov., provide diagnostic characters with illustrations, and compare the new species with <i>C. violacea</i>. The species occurs in mid- to high-elevation pine and pine-broadleaf mixed forests and differs from <i>C. violacea</i> in both elevational range and phenology, indicating potential ecological differentiation. Additionally, we document a rare instance of a nymphal parasitengone mite (cf. Erythraeidae) attached to one female specimen.