Pteronemobius arima Otte & Alexander 1983
Creators: name: Hegg, Danilo
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Trigonidiidae
Pteronemobius
Pteronemobius arima

description: Pteronemobius cf. arima Otte & Alexander, 1983
Figs 6–7, 8C–D, 25–26, 27G–L, 28D–F, 38F
Diagnosis
A small ground cricket (body length 4 to 6 mm), coloured brown, with individual variation from light reddish/brown to almost black. Three subapical spurs on outer edge of Tibia III in both males and females; three subapical spurs on inner edge in females, four in males, the fourth spur being glandular. Male forewing dark with a pale stripe running along the edges; upper surface of wing is textured, matt (Fig. 8C–D); stridulatory file with 75 to 130 teeth. Female forewing with both short (Fig. 28F) and long (Fig. 28E) morphs; individuals with fully developed hindwings common.
Material examined (see also Supp. file 1: Table S7)
NEW ZEALAND – Taranaki (TK) • 1 ♂; Bell Block, New Plymouth; 39.02408° S, 174.14423° E; 20 m a.s.l.; 30 Mar. 2022; D. Hegg leg.; in grass; insect net; MPN OR0249 • 1 ♂; Bell Block, New Plymouth; 39.02314° S, 174.14505° E; 20 m a.s.l.; 31 Mar. 2022; D. Hegg leg.; in grass; insect net; MPN OR0250 • 1 ♂; Awakino Gorge; 38.62087° S, 174.74416° E; 130 m a.s.l.; 19 Mar. 2024; D. Hegg leg.; in lawn; trowel and jar; MPN OR0325. – Taupō (TO) • 1 ♂, 2 ♀♀; Taumarunui; 38.88301° S, 175.26033° E; 200 m a.s.l.; 2 Apr. 2022; D. Hegg leg.; in lawn; jar; MPN OR0252 to OR0254. – Coromandel / Bay of Plenty (CL/ BP) • 1 ♀; Waihi; 37.39444° S, 175.84915° E; 100 m a.s.l.; 12 Apr. 2023; D. Hegg leg.; on footpath; insect net; MPN OR0251. – Auckland (AK) • 2 ♂♂, 1 ♀; Avondale Motor Park, Auckland; 36.89795° S, 174.70778° E; 40 m a.s.l.; 28 Mar. 2022; D. Hegg leg.; on sparsely vegetated ground; jar; MPN OR0256 to OR0258. – Northland (ND) • 1 ♂; Whangārei; 35.70408° S, 174.3532° E; 100 m a.s.l.; 1 Aug. 2023; D. Hegg leg.; in car park; jar; MPN OR0255 • 1 ♂, 1 ♀; Kerikeri; 35.24029° S, 173.93822° E; 100 m a.s.l.; 22 Mar. 2022; D. Hegg leg.; in tall grass; insect net; MPN OR0223, OR0234 • 5 ♂♂, 10 ♀♀; Kerikeri; 35.22795° S, 173.94853° E; 50 m a.s.l.; 21 Mar. 2022; D. Hegg leg.; on footpath; jar; MPN OR0224 to OR0233, OR0235 to OR0239 • 1 ♂; Springbank Rd, Kerikeri; 35.24249° S, 173.92505° E; 100 m a.s.l.; 1 Apr. 2024; D. Hegg leg.; in lawn; jar; MPN OR0385 • 1 ♀; Mahinepua Peninsula Track; 34.99595° S, 173.84891° E; 20 m a.s.l.; 30 Apr. 2021; D. Hegg leg.; short grass on walking track; insect net; MPN OR0482 • 4 ♂♂, 4 ♀♀; Maitai Bay, Karikari Peninsula; 34.82342° S, 173.40619° E; 30 m a.s.l.; 5 Dec. 2022; D. Hegg leg.; in grass; trowel and jar; MPN OR0240 to OR0247 • 7 ♂♂, 4 ♀♀; same data as for preceding; 28 Mar. 2024; MPN OR0359 to OR0369 • 1 ♀; Kapowairua campsite, Spirits Bay; 34.42586° S, 172.86203° E; 10 m a.s.l.; 25 Mar. 2022; D. Hegg leg.; in grass; jar; MPN OR0248.
Description
A detailed description of Pteronemobius cf. arima is not included here, since I am not designating or describing a new species, nor would I know how to differentiate it from P. arima proper, assuming it is different at all. Images of the main characters are in Figs 8D, 25 and 27G–L.
MEASUREMENTS. See Table 6, also Figs 6–7. No sexual dimorphism.
SONG. A very quiet sequence of chirps, rather like a mere whisper, difficult to record. Peak frequency between 6 kHz and 7 kHz, each chirp approx. 0.2 seconds in length; interval between chirps between 0.4 and 0.7 seconds long. Pulse rate approx. 40 pulses per second. See also Fig. 26 and Table 6.
Habitat and ecology
Pteronemobius cf. arima is a nocturnal species, more tolerant of dry conditions than P. truncatus. It inhabits a variety of grassland habitats, including swamp, rank grass, lawns and sports fields.
Pteronemobius cf. arima often forms mixed populations with the larger Pteronembius truncatus and with ground crickets in the genus Bobilla, with which it could easily be confused.
Distribution
Native of Australia, region unknown. New Zealand: relatively common in northern half of North Island (Fig. 38F).
description: Published as part of Hegg, Danilo, 2024, Small crickets of New Zealand (Orthoptera: Grylloidea: Trigonidiidae and Mogoplistidae), with the description of two new genera and species, pp. 1-87 in European Journal of Taxonomy 955 (1) on pages 52-57, DOI: 10.5852/ejt.2024.955.2655, http://zenodo.org/record/13742408