Pleioplectron simplex Hutton, 1896

Figs 2 A–B, 3, 4A–B, 5, 6A, 7A, 8A–C, 10A–C, 12A, 14A–B, 18B

Pleioplectron simplex Hutton, 1896: 233, pl. 13, figs 13–13e.

Pleioplectron pectinatum Hutton, 1896: 234 . syn. nov.

Diagnosis

A medium-sized cave wētā found in forested and urban areas in the southern South Island, east of the mountains, mainly in inland Canterbury and the east coast. It is very common in highly modified environments, including around dwellings and firewood piles; Pleioplectron simplex is ‘the’ urban cave wētā of New Zealand’s South Island. Being chequered grey-brown in colour, often with a prominent yellow median line running along the length of the dorsum, it could be most easily mistaken for P. thomsoni (Chopard, 1923) comb. nov., with which it is sympatric, and with P. triquetrum sp. nov. at the northern end of its distribution range. It is readily distinguished from both of these species by lacking a retrolateral apical spine on the fore femur. Pleioplectron simplex is generally darker in colour compared to P. thomsoni comb. nov. and lighter compared to P. triquetrum sp. nov.

Etymology

Not explained by Hutton; ʻ simplex ʼ is Latin for ʻsimpleʼ or ʻplainʼ.

Material examined (see also Table 2 in Supplementary Material)

Lectotype NEW ZEALAND • ♂, adult; Mid Canterbury (MC); date unknown; F.W. Hutton leg.; CMNZ 000280.

Other material

NEW ZEALAND – Mid Canterbury (MC) • 1 ♂, holotype of P. pectinatum; Banks Peninsula; 43.7° S, 173° E; date unknown; F.W. Hutton leg.; CMNZ 000266 • 1 ♂, paratype of P. pectinatum [labelled as “paralectotype”]; Christchurch; 43.5° S, 172.6° E; unknown date; F.W. Hutton leg.; CMNZ 000266a • 1 ♂, 1 ♀; Lake Ellesmere, Motukarara; 43.72448° S, 172.59575° E; 20 m a.s.l.; 26 May 2016; C. Putwain leg.; MPN CW 2976, CW 2977 • 2 ♂♂; Banks Peninsula, Hinewai Reserve; 43.81095° S, 173.02865° E; 460 m a.s.l.; 29 Mar. 2017; D. Hegg leg.; in basement of keeper’s house; insect net; MPN CW 3001, CW3002 • 5 ♂♂, 2 ♀♀; Banks Peninsula, Hinewai Reserve; 43.81510° S, 173.02819° E; 280 m a.s.l.; 22 Sep. 2018; D. Hegg leg.; on stream bank; night search + insect net; MPN CW 4109 to CW 4114, CW4118 • 5 ♂♂, 3 ♀♀; Banks Peninsula, Wainui; 43.80957° S, 172.91348° E; 0 m a.s.l.; 30 Nov. 2012; B. Taylor-Smith and M. Morgan-Richards leg.; leaf litter, forest fragment; night search; MPN CW 2137, CW 2186 to CW 2188, CW 2201, CW 2403, CW 2418, CW 2463 • 1 ♂, 3 ♀♀; Waimakariri River, Cass field station; 43.03585° S, 171.76077° E; 600 m a.s.l.; 25 Feb. 2006; J. Whitfeld leg.; rooty overhang near stream; MPN CW 327A, CW 327B, CW 328, CW329 • 1 ♀; Craigieburn, Helicopter Hill Track; 43.14628° S, 171.72807° E; 800 m a.s.l.; 19 Mar. 2006; P.M. Johns and R. Pratt leg.; in native forest; pitfall trap; MPN CW 359 • 2 ♀♀; same locality as preceding; 10 Feb. 2017; D. Hegg leg.; clay bank on side of walking track; night search; MPN CW 3459, CW3914 • 1 ♀; Porters Pass, Foggy Peak; 43.29361° S, 171.74232° E; 1000 m a.s.l.; 19 Mar. 2006; P.M. Johns and R. Pratt leg.; near stream; pitfall trap; MPN CW 361 • 3 ♀♀, 1 ♂; Lake Coleridge, H.E. Hart Arboretum; 43.36282° S, 171.53006° E; 400 m a.s.l.; 18 Nov. 2016; D. Hegg leg.; exotic forest; night search + insect net; MPN CW 3178 to CW 3181 • 1 ♀, 1 nymph; Mt Somers, Sharplin Falls; 43.62802° S, 171.4167° E; 500 m a.s.l.; 13 Oct. 2017; D. Hegg leg.; under boulder in native forest; night search + insect net; MPN CW 3786, CW 4001 . – Dunedin (DN) • 4 ♂♂, 1 ♀; Long Beach; 45.7444° S, 170.6406° E; 0 m a.s.l.; 10 May 2016; D. Hegg leg.; in sea cave; night search + insect net; MPN CW 3009 to CW 3013 • 1 ♂; same collection data as for preceding; 8 Nov. 2016; MPN CW 4013 • 1 ♂; Opoho; 45.85399° S, 170.5339° E; 120 m a.s.l.; 14 Feb. 2016; D. Hegg leg.; in wooden retaining wall on roadside; night search + insect net; MPN CW 2821 • 1 ♂, 1 nymph; Otago Boys’ High School; 45.87083° S, 170.49588° E; 100 m a.s.l.; 18 Oct. 2016; D. Hegg and R. Roe leg.; in school basement; photograph only; iNaturalist 4382005 [with link from table] • 1 ♀; Caversham; 45.89803° S, 170.48239° E; 20 m a.s.l.; 14 Mar. 1999; MMR and S. Trewick leg.; under house; day search; MPN CW 306. – Southland (SL) • 1 ♀; Awarua Bay; 46.56126° S, 168.45545° E; 0 m a.s.l.; 2013; T. Jewell leg.; beneath dead wood; MPN CW2558 • 1 ♂; Invercargill, Otatara; 46.43639° S, 168.28637° E; 10 m a.s.l.; 4 Dec. 2006; P.M. Johns leg.; in drain pipes in urban garden; MPN CW663 • 1 ♂, 1 ♀; Bluff Hill; 46.61625° S, 168.34024° E; 220 m a.s.l.; 2013; T. Jewell leg.; under rocks in manuka shrubland; MPN CW2562, CW2563 .

Description

MEASUREMENTS. See Table 1.

Originally described by Hutton (1896), the species was redescribed adequately by Richards (1959). A notable detail omitted by both Hutton (1896) and Richards (1959) is the presence of sensory hair tuffs on the antennal segments of some, but not all, sexually mature males (Fig. 5).

Male Pleioplectron simplex on Banks Peninsula tend to reach larger dimensions than elsewhere, but our genetic data provide no evidence that the Banks Peninsula population is distinct. Of five adult males we measured from Banks Peninsula, the smallest (MPN CW4112) measured 16.3 mm in body length, 12% longer than the largest adult male we collected elsewhere (MPN CW4013 from Long Beach, Dunedin, 14.5 mm long). To avoid introducing geographical bias in our measurements, we only included one adult male P. simplex from Banks Peninsula in Table 1, which gives us an estimate for the maximum size of the species.