A large (males 35–71 millimeter), glossy, brown-black stag beetle.

The male's jaws are long, quite straight, with an inward-facing tooth just outside the middle, with scattered, small teeth along the inner edge, pointed at the tip.

The antennas are quite thin, with a small, six-joint fan.

The female is completely black, much smaller than the male, with no strikingly enlarged jaws.

[2] The larvae develop in rotten tree trunks.