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Sigaus

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Sigaus
Sigaus piliferus
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Orthoptera
Suborder: Caelifera
Family: Acrididae
Tribe: Catantopini
Genus: Sigaus
Hutton, 1897[1]
Species

Sigaus australis
Sigaus campestris
Sigaus crassicauda
Sigaus collinus
Sigaus childi
Sigaus dugdali
Sigaus minutus
Sigaus nitidus
Sigaus nivalis
Sigaus piliferus
Sigaus robustus
Sigaus tumidicauda
Sigaus villosus

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[2] 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[3] all are adapted to cold conditions,[4] and many are coloured for camouflage against rocky ground.[5][6] The largest species Sigaus villosus can reach 48mm (body length of adult female).[5] The smallest species Sigaus minutus and S. childi are threatened with extinction.[7]

Taxonomy

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The taxonomy of New Zealand endemic grasshoppers was substantially revised by Bigelow in 1967, based mostly on female genitalia,[5] and again in 2023 using genetic data.[3] 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.[3] 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.[8] The genus is monophyletic and sister to grasshoppers from Tasmania, Australia.[9]

Sigaus australis Sigaus campestris Sigaus childi Sigaus australis (homerensis) Sigaus minutus Sigaus piliferus Sigaus australis (obelisci) Sigaus australis (takahe) Sigaus villosus
Photograph
Elevation[10] 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)
Described[11] 1897[1]
Hutton
1897
Hutton
1999[12]
Jamieson
2003[13]
Morris
1967[14]
Bigelow
1897
Hutton
1967
Bigelow
2003
Morris
1950[15]
Salmon
Habitat[16] Tussock grasslands Dry rocky hillsides/
tussock grasslands
Dry rocky hillsides Tussock grasslands Fluvial outwash Tussock grasslands Alpine lichen fields Tussock grasslands Scree
Polymorphism[17] Highly cryptic Highly cryptic Highly cryptic 2 Highly cryptic 2 Highly cryptic 1
Regions Canterbury
Otago
Canterbury
Otago
Southland
Otago Southland Canterbury Waikato
Gisborne
Hawke's Bay
Manawatū-Whanganui
Wellington
Otago Southland Canterbury
Size[18] Medium Medium/large Medium Medium Very small Large Large Medium Large
Status[19] Not threatened Not threatened Nationally Critical Range Restricted Nationally Endangered Not threatened Range Restricted Range Restricted Not threatened
Wings[20] Micropterous
2–3 mm
Micropterous
2–3 mm
Micropterous
1–2 mm
Micropterous
2–3 mm
Micropterous
1 mm
Micropterous
3–4 mm
Micropterous
3–4 mm
Micropterous
2–4 mm

References

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  1. ^ a b Hutton, F.W. 1897: "The grasshoppers and locusts of New Zealand and the Kermadec Islands". Transactions of the New Zealand Institute 30: 135-50
  2. ^ Meza-Joya, Fabio Leonardo; Morgan-Richards, Mary; Trewick, Steven A. (2024). "Phenotypic and genetic divergence in a cold-adapted grasshopper may lead to lineage-specific responses to rapid climate change". Diversity and Distributions. 30 (6). doi:10.1111/ddi.13848. ISSN 1366-9516.
  3. ^ a b c Trewick, Steven A.; Koot, Emily M.; Morgan-Richards, Mary (2023). "Māwhitiwhiti Aotearoa: Phylogeny and synonymy of the silent alpine grasshopper radiation of New Zealand (Orthoptera: Acrididae)". Zootaxa. 5383 (2): 225–241. doi:10.11646/zootaxa.5383.2.7. ISSN 1175-5334.
  4. ^ Koot, Emily M.; Morgan-Richards, Mary; Trewick, Steven A. (2022). "Climate change and alpine-adapted insects: modelling environmental envelopes of a grasshopper radiation". Royal Society Open Science. 9 (3). Bibcode:2022RSOS....911596K. doi:10.1098/rsos.211596. ISSN 2054-5703. PMC 8889178. PMID 35316945.
  5. ^ a b c Bigelow, R.S. 1967. The Grasshoppers of New Zealand, Their Taxonomy and Distribution. University of Canterbury, Christchurch. p. 60.
  6. ^ Jamieson, Colleen D. (1999). "A new species of Sigaus from Alexandra, New Zealand (Orthoptera: Acrididae)". New Zealand Journal of Zoology. 26 (1): 43–48. doi:10.1080/03014223.1999.9518176. ISSN 0301-4223.
  7. ^ Trewick, S. A.; Morris, S. J.; Johns, P. M.; Hitchmough, R. A.; Stringer, I. A.N. (2012). "The conservation status of New Zealand Orthoptera". New Zealand Entomologist. 35 (2): 131–136. Bibcode:2012NZEnt..35..131T. doi:10.1080/00779962.2012.686318. ISSN 0077-9962. S2CID 219564547.
  8. ^ 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.
  9. ^ Koot, Emily M.; Morgan-Richards, Mary; Trewick, Steven A. (2020). "An alpine grasshopper radiation older than the mountains, on Kā Tiritiri o te Moana (Southern Alps) of Aotearoa (New Zealand)". Molecular Phylogenetics and Evolution. 147: 106783. Bibcode:2020MolPE.14706783K. doi:10.1016/j.ympev.2020.106783. ISSN 1055-7903. PMID 32135305. S2CID 212567788.
  10. ^ Species prefer altitude.
  11. ^ The author and year the species was described.
  12. ^ A new species of Sigaus from Alexandra, New Zealand (Orthoptera: Acrididae). New Zealand Journal of Zoology, 26: 43-48.
  13. ^ Morris, S.J. 2003: "Two new species of Sigaus from Fiordland, New Zealand (Orthoptera: Acrididae)". New Zealand entomologist, 26: 65–74. PDF Archived 2011-07-21 at the Wayback Machine
  14. ^ Bigelow, R.S. 1967: The Grasshoppers of New Zealand, Their Taxonomy and Distribution. University of Canterbury, Christchurch.
  15. ^ Salmon, 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 1950
  16. ^ Species prefer habitat.
  17. ^ The number of colour morphs known for adults of this species.
  18. ^ Size for adult males: Small less than 6 mm; Medium 6-30 mm & Large greater than 30 mm.
  19. ^ Base on the New Zealand Threat Classification System
  20. ^ Species wing length.
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