Sigaus crassicauda is a species of alpine grasshopper endemic to New Zealand.[1] Like all of New Zealand sub-alpine and alpine grasshoppers S. crassicauda has a 2 or 3 years life cycle. The eggs must ‘overwinter’ before they will hatch. Grasshoppers are found throughout the year and adult grasshoppers can be found throughout the New Zealand summer between December and April. Sigaus crassicauda cannot fly.
Sigaus crassicauda is only known from West Coast Region and Tasman Region of New Zealand.[2] It can be found as far south as the Right Branch of the Rahu River, Spring Junction (-42.2918°N 172.1233°W) and as far north as the Thousand Acres Plateau, Matiri Range (-41.5936°N 172.3225°W). Alpinacris crassicauda prefer alpine tussock grasslands between 1200m-1500mm (3,900feet-4,900feetm), however, can be found as low as 1020m (3,350feet) on the Thousand Acres Plateau, Matiri Range (-41.5936°N 172.3225°W). Climate change is likely to reduce the suitable habitat that this species can occupy by 10 - 60% of its current range.[3]
The wings on S. tumidicauda are micropterous (small wings) between 2mm4mm making this species flightless like most of New Zealand grasshoppers. Male body length 18mm22mm; Female body length 25mm35mm.
Sigaus crassicauda was described in 1967 by Robert Sidney Bigelow, in the genus Alpinacris[4] , with type locality of Lead Hills, Boulder Lake (-40.8931°N 172.549°W). A male holotype and paratype are deposited in the Canterbury Museum, Christchurch.