This species was discovered by the lighthouse keeper Andreas Sandager on
North Brother Island in
Cook Strait, and was described by
Broun in 1881. It is currently only found on islands in the outer
Marlborough Sounds in New Zealand; Islands that it has been collected from include the Brothers,
Stephens Island, Middle and South Trio Island,
Maud Island and Sentinel Rock. It has not been seen since 1957 on North Brother Island (its type locality) despite searches, and it is possible that it is now extinct there. The relict populations on Marlborough Sounds islands are probably due to the introduction of mammalian predators on the mainland. == Ecology ==