Molecular evidence for the taxonomic resurrection of Stenurella sennii nom. res. within the phylogeographic framework of S. melanura (Coleoptera, Cerambycidae)

We utilized DNA barcoding to analyze 241 mitochondrial COI sequences of Stenurella melanura across its European range, establishing a framework for understanding its intraspecific genetic variation with four genetically distinct haplogroups ( Sm1–Sm4 ). The two most widespread lineages, Sm1 and Sm2 , show a strong association with dorsal pube s cence coloration, particularly of the elytra: Sm1 is dominated by light-pubescent individuals, whereas Sm2 predominantly comprises dark-pubescent forms. Instances of discordance between haplogroup and pubescence coloration are best e x plained by ongoing hybridization, with geographically structured distributions across Europe, reflecting complex postgl a cial biogeography. Phylogenetic analysis revealed two highly divergent sequences forming a distinct clade , separated from S. melanura by a mean genetic distance of 0.077 substitutions per site. Morphological examination confirmed their co n formity with the original description of Stenurella sennii nom. res. , validating the taxonomic restoration of this neglected species. As S. sennii nom. res. is a cryptic sibling species morphologically indistinguishable from light-pubescent Sm1 haplogroup of S. melanura , traditional identification fails to capture this diversity. Our pan-European phylogeographic framework resolves this confusion, demonstrating that molecular diagnostics are essential for accurate species delimitation and for maintaining the integrity of taxonomic inventories.