A very common species of southestern Otago, Southland and Stewart Island. In Otago it reaches into the Taieri Plains as far north as the Lee Stream. It apparently is absent from the volcanics of the Otago Peninsula and the coastal hills down to Taieri Mouth. It does not venture into the uplands around the Taieri Gorge which are occupied by Megadromus fultoni, and has only a few isolated populations around Lakes Te Anau and Manapouri.

Its basic colour is black but it has greenish, coppery and purple, almost iridescent sheens.