About Lucanus formosanus Planet, 1899
Lucanus formosanus Planet, 1899 is a species of stag beetle endemic to Taiwan. Adult individuals of this species reach a total length of 45–80 millimetres, which equals 1.8–3.1 inches. Similar to other species belonging to the lucanid beetle family, L. formosanus shows clear sexual dimorphism, and males of the species also have corresponding external morphological allometry. Male L. formosanus develop mandibles that differ in form based on their geographic location, forming three distinct morphs: northern, central, and southern.
