Mecodema oconnori is a large-bodied species of ground beetle that is found mainly on the western regions of the North Island, New Zealand.

[1][2][3] It is mainly found in native forest habitats, both intact and fragmented, and on the edges of pine (Pinus radiata) plantations.

[4] Mecodema oconnori is one of the few species of New Zealand carabids that has any published ecological or life history studies and/or observations.

This species is relatively long-lived and only produces a small number of eggs in a season.

The female broods the eggs, as well as the larvae, in a burrow beneath logs or rocks.