Sigaus is a genus of grasshoppers in the tribe Catantopini that is endemic to New Zealand. All but one Sigaus species is endemic to the South Island: Sigaus piliferus is the only North Island representative and is the type species. Most species in this genus are restricted to alpine habitats. All are wingless and make no sounds.
There are thirteen species in the genus all are adapted to cold conditions, and many are coloured for camouflage against rocky ground.Bigelow, R.S. 1967. The Grasshoppers of New Zealand, Their Taxonomy and Distribution. University of Canterbury, Christchurch. p. 60. The largest species Sigaus villosus can reach 48mm (body length of adult female). The smallest species Sigaus minutus and S. childi are threatened with extinction.
Taxonomy The taxonomy of New Zealand endemic grasshoppers was substantially revised by Bigelow in 1967, based mostly on female genitalia, and again in 2023 using genetic data. The New Zealand radiation of cold-adapted grasshoppers is monophyletic but neither genetics nor morphology resolve distinctive genera, therefore it was suggested that all thirteen species be placed in the genus Sigaus. The genus Sigaus is distinguished from other Acrididae as flightless, silent acridids with short tegmina, crypsis colouration and endemic to New Zealand. Each species has distinctive pronotum shape and structures of the internal male genitalia: the epiphallus lophi are saddle-like in shape with the mesal protuberance of the lophus having a smooth, rounded outline.Morris, S.J. 2002: Identification guide to grasshoppers (Orthoptera: Acrididae) in Central Otago and Mackenzie Country. DOC Science Internal Series 26. Department of Conservation, Wellington. 17 p. The genus is monophyletic and sister to grasshoppers from Tasmania, Australia.
Sigaus australisSigaus campestrisSigaus childiSigaus australis (homerensis)Sigaus minutusSigaus piliferusSigaus australis (obelisci)Sigaus australis (takahe)Sigaus villosusPhotograph ElevationSpecies prefer altitude. 1,300–1,700 m (4,300–5,600 ft) 400–1,500 m (1,300–4,900 ft)200–500 m(660–1,600 ft)900–1,000 m (3,000–3,300 ft) 300–800 m (980–2,600 ft) 1,600–1,800 m (5,200–5,900 ft) 1,000–1,400 m (5,900–6,900 ft)1,800–2,100 m (–6,900 ft)DescribedThe author and year the species was described. 1897Hutton, F.W. 1897: "The grasshoppers and locusts of New Zealand and the Kermadec Islands". Transactions of the New Zealand Institute 30: 135-50Hutton 1897Hutton 1999A new species of Sigaus from Alexandra, New Zealand (Orthoptera: Acrididae). New Zealand Journal of Zoology, 26: 43-48.Jamieson 2003Morris, S.J. 2003: "Two new species of Sigaus from Fiordland, New Zealand (Orthoptera: Acrididae)". New Zealand entomologist, 26: 65–74. PDF Morris 1967Bigelow, R.S. 1967: The Grasshoppers of New Zealand, Their Taxonomy and Distribution. University of Canterbury, Christchurch.Bigelow 1897Hutton 1967Bigelow 2003Morris 1950Salmon, J.T. 1950: A new species of Acrididae (Insecta: Orthoptera) from New Zealand. Transactions of the Royal Society of New Zealand, Vol. 78, Part 1, page 69, February 1950SalmonHabitatSpecies prefer habitat. Tussock grasslands Dry rocky hillsides/tussock grasslands Dry rocky hillsides Tussock grasslands Fluvial outwash Tussock grasslands Alpine lichen fields Tussock grasslands ScreePolymorphismThe number of colour morphs known for adults of this species. Highly cryptic Highly cryptic Highly cryptic 2 Highly cryptic 2 Highly cryptic 1RegionsCanterburyOtagoCanterburyOtagoSouthlandOtagoSouthlandCanterburyWaikatoGisborneHawke's BayManawatū-WhanganuiWellingtonOtagoSouthlandCanterburySizeSize for adult males: Small less than 6 mm; Medium 6-30 mm & Large greater than 30 mm. Medium Medium/large Medium Medium Very small Large Large Medium LargeStatusBase on the New Zealand Threat Classification System Not threatened Not threatened Nationally Critical Range Restricted Nationally Endangered Not threatened Range Restricted Range Restricted Not threatenedWingsSpecies wing length. Micropterous2–3 mm Micropterous2–3 mm Micropterous1–2 mm Micropterous2–3 mm Micropterous1 mm Micropterous3–4 mm Micropterous3–4 mm Micropterous2–4 mm
References
External links
Sigaus discussed on RNZ Critter of the Week, 3 March 2017 Citizen science observations in iNaturalist