Quantitative image analysis applied to revise the taxonomy of the Palearctic Earophila badiata species group (Lepidoptera: Geometridae: Larentiinae)

The geometrid moth Earophila badiata (Denis & Schiffermüller, 1775), which occurs widely in the Palearctic realm, has rapidly filled a large gap in its range across southern Finland during the past two decades, prompting a re-evaluation of its taxonomy. Using an integrative taxonomic approach including a quantitative wing image analysis combined with genitalia morphology and mitochondrial DNA barcoding (mtCOI) analyses, we reassessed the status of the described taxa within the E. badiata species group. Quantitative analysis of forewing colours revealed strong sexual dimorphism and significant effects of specimen wear and age on colouration, but no consistent morphological differences between the nominotypical subspecies E. badiata badiata and taxon E. badiata fennokarelica (Kaisila, 1945). Comparative genitalia morphology, including micro-CT imaging, showed no diagnostic differences among closely related E. badiata , E. kolomietsi Vasilenko, 2003, and E. pseudobadiata Vasilenko, 2007, supporting the synonymy of these taxa. Molecular phylogeny and haplotype analysis confirmed monophyly among Eurasian samples with low genetic divergence (<0.63%), but implying a distinct lineage for North African E. badiata tellensis (Herbulot, 1957). Based on these findings, we propose synonymizing E. kolomietsi and E. pseudobadiata with E. badiata syn. n. and classify the E. badiata taxon fennokarelica as a morphological form of E. badiata below the subspecific rank. Our results challenge the current subspecies delineation and support a revision of taxonomic boundaries within this group, highlighting the value of integrative taxonomy for resolving complex relationships among closely related species.