Pteronemobius truncatus (Saussure, 1877)

Figs 5–7, 8A–B, 23–24, 27A–F, 28A–C, 38E

Nemobius truncatus Saussure, 1877: 259 .

Nemobius laparinthae Tepper, 1896: 378 .

Pteronemobius mjobergi Chopard, 1925: 9 .

Nemobius larapinthae [sic] – Kirby 1906: 16.

Pteronemobius truncatus – Chopard 1951: 427. — Otte & Alexander 1983: 167–169, figs 124, 128–129, 130a–b, 132b, s. — Baehr 1989: 19. — Messenger 1991: 22. — Hollier et al. 2013: 528. — Rentz & Su 2019: 339–340.

Diagnosis

A medium- to large-sized ground cricket (body length 6 to 9 mm), coloured brown. Legs with four subapical spurs on both inner and outer edge of Tibia III in both males and females; fourth inner subapical spur is glandular in males. Male forewing light brown in colour, shiny; it reflects light like a mirror (Fig. 8A–B); stridulatory file with 97 to 110 teeth. Female forewing has both short (Fig. 28B) and long (Fig. 28C) morphs; individuals with fully developed hindwings are common.

Etymology

Latin, ‘ truncatus ’ (adj. perf. inf. of ‘ trunco ’) means ‘maimed’, ‘mutilated’. No explanation for the name was given in Saussure (1877).

Material examined (see also Supp. file 1: Table S6)

Holotype

AUSTRALIA • ♀, adult; 1847; J. Verraux leg.; MNHN EO-ENSIF10379.

Paratypes

AUSTRALIA • 1 ♀; Queensland, Alice River; E. Mjöberg leg.; MNHN EO-ENSIF10381 • 1 ♂; Queensland, Malanda; E. Mjöberg leg.; MNHN EO-ENSIF10382 .

Other material

NEW ZEALAND – Nelson (NN) • 1 ♀; Kaiteriteri, Tasman Bay; 41.04248° S, 173.01902° E; 0 m a.s.l.; 18 Mar. 2023; C. Stephens leg.; on beach; photograph only; iNaturalist 152116367. – Wanganui (WI) • 1 ♀; Foxton Beach; 40.46270° S, 175.22160° E; 10 m a.s.l.; 4 May 2019; M. Pélissié leg.; near pond; MPN OR0029 • 1 ♀; Ashhurst; 40.28221° S, 175.74729° E; 100 m a.s.l.; 27 Jan. 2023; G. Smith leg.; in house porch; photograph only; iNaturalist 147712667. – Taupō (TO) • 1 ♂; Lake Rotopounamu; 39.02648° S, 175.7308° E; 715 m a.s.l.; 30 Mar. 2019; M. Pélissié leg.; on lake shore; MPN OR0023. – Taranaki (TK) • 2 ♂♂, 1 ♀; Bell Block, New Plymouth; 39.02314° S, 174.14505° E; 20 m a.s.l.; 30–31 Mar. 2022; D. Hegg leg.; in lawn near pond; insect net at night; MPN OR0199 to OR0201 • 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 OR0324. – Waikato (WO) • 1 ♀; Manganui Road, Awakino; 38.61659° S, 174.67720° E; 50 m a.s.l.; 29 Mar. 2022; D. Hegg; on grassy road verge; insect net; MPN OR218 • 2 ♀♀; Leitchs Clearing, Herangi Range; 38.43453° S, 174.76800° E; 270 m a.s.l.; 2 Apr. 2022; D. Hegg leg.; in tall grass; trowel and jar; MPN OR0219, OR0220 • 4 ♂♂, 12 ♀♀; Top10 Holiday Park, Cambridge; 37.90592° S, 175.47985° E; 60 m a.s.l.; 13–14 Mar. 2022; D. Hegg leg.; in men’s bathroom; jar; MPN OR0202 to OR0217 • 2 ♂♂, 3 ♀♀; same data as for preceding; 24 Mar. 2024; MPN OR0344 to OR0348 • 1 ♀; Leitchs Hut, Herangi Range; 38.43333° S, 174.77956° E; 250 m a.s.l.; 21 Mar. 2024; D. Hegg leg.; in tall grass; trowel and jar; MPN OR0335 • 1 ♂; Mangatoa Saddle; 38.41638° S, 174.72193° E; 300 m a.s.l.; 22 Mar. 2024; D. Hegg leg.; dry dirt in car park; trowel and jar; MPN OR0336. – Bay of Plenty (BP) • 1 ♂, 1 ♀; Hurunui Hut, Kaimai Range; 37.81712° S, 175.92802° E; 540 m a.s.l.; 15–16 Apr. 2023; D. Hegg leg.; next to stream; insect net; MPN iNat OR0221, OR0222. – Bay of Plenty / Coromandel (BP/ CL) • 1 ♂, 4 ♀♀; Waihi; 37.38992° S, 175.83290° E; 100 m a.s.l.; 25 Mar. 2024; D. Hegg leg.; in lawn; jar; MPN OR0349 to OR0353. – Coromandel (CL) • 1 ♀; Coromandel; 36.76166° S, 175.49129° E; 5 m a.s.l.; 6 Apr. 2024; D. Hegg leg.; in lawn; jar; MPN OR0397. – Auckland (AK) • 1 ♀; Tahuna Torea Reserve, Auckland; 36.87249° S, 174.88177° E; 0 m a.s.l.; 26 Mar. 2024; D. Hegg leg.; in lawn; jar; MPN OR0354 • 2 ♂♂; Ellerslie Palms Motel, Auckland; 36.89635° S, 174.83458° E; 30 m a.s.l.; 26 Mar. 2024; D. Hegg leg.; in lawn; jar; MPN OR0355, OR0356. – Northland (ND) • 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 OR0386 • 3 ♂♂, 4 ♀♀; Kohuroanaki Loop Track, Te Paki; 34.50864° S, 172.82443° E; 90 m a.s.l.; 4 Dec. 2022; D. Hegg leg.; near water on 4WD track; insect net; MPN OR0191 to OR0198 .

Description

Refer to the detailed description in Otte & Alexander (1983: 167–169). See also Fig. 23 in this work.

MEASUREMENTS. See Table 6, also Figs 6–7. No sexual dimorphism.

SONG. A sequence of thrills with a peak frequency between 5.5 kHz and 7 kHz, each thrill up to one and a half seconds in length; interval between thrills between one and three seconds long (Figs 5, 24; Table 5). See also the detailed description in Otte & Alexander (1983: 167–169).

Habitat and ecology

Pteronemobius truncatus is a nocturnal species, almost always found in the proximity of water, including at the edge of ephemeral puddles and in saturated lawns. Swarms of winged individuals are known to form in late summer (Messenger 1991). Pteronemobius truncatus often forms mixed populations with the smaller Pteronemobius cf. arima and with ground crickets in the genus Bobilla, with which it could easily be confused.

Distribution

Native of Australia, where it is found in all coastal regions, except in the south-west (Rentz & Su 2019). New Zealand: relatively common in much of North Island; recently also found in the Nelson Region, South Island (Fig. 38E). Geographic range expanding southwards.