[2] The species survives only on the small unnamed island "Stack H", in a patch of vegetation the size of a living room, and is in extreme danger of extinction.

What distinguishes this species from all other New Zealand stag beetles is a long conical vertical tooth, on the top of the mandible, in both sexes.

[3][6] All recent surveys have only found this species on Stack H, in a "living-room sized" patch of New Zealand ice plant or horokaka (Disphyma australe);[7] it has not been seen on Lizard Island since its description in 1893.

[4][3] Geodorcus species on mainland New Zealand are associated with rotten logs, but these are absent from Stack H. The Mokohinau Islands are generally very arid, with poor moisture retention.

[4] This beetle burrows into a peat-like layer of soil formed by New Zealand ice plant (Disphyma australe).

It has also been found under rocks, in the tussock grass Chionochloa bromoides, and in the leaf litter beneath coastal pohutukawa.