Figure 4.

External morphological characters analyzed in this study. Lucanus taiwanus is used as a model species from the same genus, as its clypeal features are more distinct and more readily captured in photographs. Although not part of the focal taxa examined in this study, it provides a clear reference for morphological illustration. Abbreviations: BL: body length, EL: elytron length, PL: pronotum length, HL: head length, MBPC: Distance from mandible base to posterior margin of the clypeus, ML: mandible length, HWL: hind wing length, HWA: hind wing area.