Isoplectron virgatum Hegg & Morgan-Richards & Trewick 2024, sp. nov.
Creators: name: Hegg, Danilo
name: Morgan-Richards, Mary
name: Trewick, Steven A.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Orthoptera
Rhaphidophoridae
Isoplectron
Isoplectron virgatum

description: Isoplectron virgatum sp. nov.
urn:lsid:zoobank.org:act: CF2E5537-FF7B-4C16-9236-6A00D079407A
Figs 3, 8, 10I, 12G, 13G, 15G–I, 18G–I, 23A
Diagnosis
A small insect, pale throughout, with six to eight longitudinal stripes on the back. A retrolateral spine at the apex of the mid femur is usually absent.
Very similar to I. parallelum sp. nov. and to Talitropsis poduroides (Walker, 1871) in morphology and habitat use, but geographically separated from these two species, which are confined to North Island. It can be mistaken for striped morphs of I. ferratum sp. nov., although the latter species is arboreal and is always armed with a retro-lateral spine at the apex of the mid femur, a trait that is generally absent in I. virgatum sp. nov.
Isoplectron virgatum sp. nov. could be confused with a small, undescribed species in the genus Notoplectron, which inhabits the southern regions of the South Island’s West Coast. This species, however, appears to prefer grasslands in the low alpine zone, whereas I. virgatum is mainly a low elevation species. Notoplectron also has a smooth upper valve of the ovipositor and macroscopically different male terminalia.
Etymology
‘ Virgātus ’ (adj.) is Latin for ‘striped’.
Material examined (see also Supp. file 1: Table S7)
Holotype NEW ZEALAND • ♂, adult; Buller (BR), Ces Clarke Hut, Paparoa Range; 42.29007° S, 171.39307° E; 900 m a.s.l.; 6 Apr. 2019; D. Hegg leg.; on Phormium leaf; night search + insect net; NMNZ AI.071894.
Paratype NEW ZEALAND • 1 ♀, adult; same data as for holotype; GenBank: PP155107; NMNZ AI.071895.
Other naterial
NEW ZEALAND – Fiordland (FD) • 1 ♀; Cleft Creek, Hollyford Valley; 44.64813° S, 168.10538° E; 100 m a.s.l.; 9 Jan. 2023; J. Jack leg.; in native forest; photograph only; iNaturalist 146558750. – Westland (WD) • 1 ♀; Jackson Bay; 43.97° S, 168.61° E; 80 m a.s.l.; 1 Nov. 2019; D. Hegg leg.; on tree fern; night search + insect net; GenBank: PP155105; MPN CW4666 • 1 ♂; Awatuna, Hokitika; 42.64905° S, 171.06228° E; 40 m a.s.l.; May 2012; B. Taylor-Smith leg.; GenBank: PP155104; MPN CW2014 • 1 ♂; same data as for preceding; GenBank: PP155102; MPN CW2016 • 1 ♂; same data as for preceding; MPN CW2009 • 1 nymph; same data as for preceding; MPN CW2013. – Buller (BR) • 1 ♂; Bob’s Hut, Matakitaki River West Branch; 42.22528° S, 172.48754° E; 840 m a.s.l.; 6 Jan. 2021; D. Hegg leg.; on Astelia leaf; night search + insect net; GenBank: PP155101; MPN CW5394 • 1 ♀; same data as for preceding; MPN CW5395 • 1 ♀; same data as for holotype; MPN CW4420 • 1 nymph; Truman Track, Punakaiki; 42.09430° S, 171.34349° E; 50 m a.s.l.; 6 Dec. 2018; D. Hegg leg.; on Astelia leaf; night search + insect net; GenBank: PP155100; MPN CW4228. – Nelson (NN) • 1 nymph; Granity Pass, Mt Owen; 41.52327° S, 172.56349° E; 1200 m a.s.l.; 9 Jan. 2019; D. Hegg leg.; on Aciphylla flower; night search + insect net; GenBank: PP155106; MPN CW4290 • 1 ♀, 1 nymph; same data as for preceding; MPN CW4289, CW4291 • 1 ♂; Cave Brook, Gouland Downs; 40.89153° S, 172.35449° E; 630 m a.s.l.; 4 Feb. 2018; D. Hegg leg.; on Astelia leaf; night search + insect net; GenBank: PP155099; MPN CW3776 • 1 ♀; same data as for preceding; MPN CW3794 • 1 nymph; same data as for preceding; MPN CW3775 • 1 ♂; Heaphy River, Kahurangi NP; 40.983° S, 172.114° E; 20 m a.s.l.; 20 Feb. 2023; D. Hegg leg.; on Coprosma shrub; night search + insect net; GenBank: PP155103; MPN CW5622.
Description
MEASUREMENTS. See Table 1. Body length approximately 11 mm in both males and females.
HEAD. Vertex pale with four brown lines running from the fastigium to the anterior margin of the pronotum, two above the eyes and two near the centre. Dark streaks run from the posterior margin of each eye to the pronotum, resembling the temples in a pair of sun-glasses. Frons, clypeus and labrum pale, with two faint, vertical dark stripes below the scapes of the antennae. Scapes and pedicels variegated; all other segments of the antennae pale.
THORAX. Pale with brown dorsal lines running along the length of the thorax and continuing into the abdomen (Fig. 12G).
LEGS. Relatively short, without sexual dimorphism. The hind tibiae are on average 95% of body length in both males and females. Fore and mid femora unarmed at the apex, although a retro-lateral apical spine on the mid femur may be present on rare occasion. Hind femora armed with one to three retrolateral and prolateral ventral linear spines, the retrolateral ones being larger. Fore tibiae armed with two pairs of ventral linear spines, and with one pair of ventral apical spines. A retrolateral dorsal spine at the apex of the fore tibia is present in 50% of examined specimens. Mid tibiae armed with two pairs of ventral linear spines, one pair of ventral spines and one retrolateral dorsal spine at the apex. A prolateral dorsal spine at the apex of the mid tibia is always absent. Hind tibiae armed with about 20 dorsal linear spines (min 16, max 24) on both the anterior and the posterior edge (Fig. 13G). Hind tibiae armed at the apex with two ventral apical spines, two dorsal apical spines and two dorsal sub-apical spines; the dorsal apical spines are largest. Ventral sub-apical spines are always absent. First and second segments in hind tarsi always unarmed except at the apex.
ABDOMEN. Tergites pale, with dorsal brown stripes running longitudinally along the whole length of the insect from the pronotum to the terminalia (Figs 12G and 23A). In females only, the seventh sternite is equipped with two ventral protuberances; the eighth sternite with three ventral protuberances (Fig. 18G).
MALE TERMINALIA. Suranal plate trapezoidal with conspicuous hair tufts on the two posterior corners. The posterior margin can be either straight (Fig. 15G) or deeply notched. Subgenital plate pear-shaped; covered in sparse, thin tomentum except near the base on the sides, which are glabrous; with a pronounced keel along its whole length (Fig. 15H). Cerci on average 20% of body length, covered in sparse, mostly short hair; tapering gradually along their whole length and ending with a blunt tip at the apex. Styli tapering and not reaching to the apex of the subgenital plate. Paraprocts with parallel sides, tapering to a sharp tip only near the apex; glabrous except for a single row of spinules near the interior margin (Fig. 15G).
FEMALE TERMINALIA. Subgenital plate consists of two bulging, rounded lobes, joined at the base and diverging at the apex; glabrous on the inner surface, covered in stout hair on the outer surface (Fig. 18G). Ovipositor on average three quarters of body length; curving gently upwards from the base to the apex; lower valve with 8 to 10 teeth below at the apex; dorsal surface of upper valve serrated in distal third (Fig. 18H–I).
Distribution and habitat
Isoplectron virgatum sp. nov. is mainly found on the elongated leaves of shrubs in the genera Phormium J.R.Forst. & G.Forst. and Astelia Banks & Sol. ex R.Br., where the insect’s habitus blends in with the leaf’s longitudinal nervature. Distributed along the West Coast of South Island from Fiordland to Kahurangi (Fig. 10I).
description: Published as part of Hegg, Danilo, Morgan-Richards, Mary & Trewick, Steven A., 2024, Revision of the New Zealand cave wētā genus Isoplectron Hutton (Orthoptera: Rhaphidophoridae), with synonymy of Petrotettix Richards and Setascutum Richards, and the description of a new genus, pp. 1-75 in European Journal of Taxonomy 971 on pages 47-48, DOI: 10.5852/ejt.2024.971.2761, http://zenodo.org/record/14451786