Isoplectron maculatum 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 maculatum

description: Isoplectron maculatum sp. nov.
urn:lsid:zoobank.org:act: D7BC8F91-27ED-42D8-9E63-CE84613D39E3
Figs 3, 8, 10G, 12E, 13F, 15D–F, 18D–F, 20D, 22B
Diagnosis
Slightly smaller than the closely related I. serratum, it can only be differentiated from the latter species by examination of the male terminalia. The two species, however, are allopatric. I. maculatum sp. nov. has a chequered yellow/ black coloration in adults.
The distribution range of I. maculatum sp. nov. may overlap with Pharmacus montanus. Isoplectron maculatum is most easily differentiated from the latter species by the long, slender legs, the presence of dorsal linear spines on the first two segments of the hind tarsi and the serrated upper valve of the ovipositor.
Etymology
‘ Măcŭlātus ’ (adj.) is Latin for ‘speckled’, after the insect’s colour pattern.
Material examined (see also Supp. file 1: Table S6)
Holotype NEW ZEALAND • ♂, adult; South Canterbury (SC), Middle Mt Peel; 43.86312° S, 171.18167° E; 1350 m a.s.l.; 19 Apr. 2019; D. Hegg leg.; on rocky outcrop on ridgeline; night search + insect net; GenBank: PP155130; NMNZ AI.071892.
Paratype NEW ZEALAND • 1 ♀, adult; same data as for holotype; NMNZ AI.071893.
Other material
NEW ZEALAND – South Canterbury (SC) • 1 ♀; same data as for holotype; MPN CW5581 • 1 ♂; same data as for holotype; 27 May 2023; GenBank: PP155129; MPN CW5641 • 1 ♀; same data as for preceding; GenBank: PP155131; MPN CW5638 • 1 ♂; same data as for preceding; MPN CW5642 • 2 ♀♀; same data as for preceding; MPN CW5639, CW5640.
Description
MEASUREMENTS. See Table 1. Body longer by 1.4 mm (12%) in females.
HEAD. Very similar to I. serratum. Like in the latter species, the lower extremity of the vertex is black, but with two conspicuous pale spots between the fastigium and the eyes. Frons and clypeus pale, with vertical dark streaks below the eyes. Labrum pale. Scapes and pedicels variegated pale and grey; all other segments of the antennae brown.
THORAX. In adults, the pronotum, mesonotum and metanotum are chequered yellow / black (Figs 12E, 22B).
LEGS. Same as I. serratum.
ABDOMEN. Chequered yellow/ black (Figs 12E, 22B). In nymphs, the whole body tends to be coloured a dull grey / green.
MALE TERMINALIA. Suranal plate trapezoidal, not as heavily sclerotised as in I. serratum (Fig. 15D). Subgenital plate same as in I. serratum; not as heavily sclerotised; with a double keel only in the distal half (Fig. 15E). Cerci short, on average 13% 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 slender, longer than subgenital plate. Paraprocts covered in dense, stout spinules on the inward-facing side; they are wider than the subgenital plate and are visible from below (Fig. 15E). Under the suranal plate there is a retractable cover which presumably protects the genitalia when not in use (Fig. 20D; compare with Fig. 15D).
FEMALE TERMINALIA. Subgenital plate consists of two narrow, rounded lobes, covered in sparse hair; separated by a gap at least twice as wide as the lobe themselves (Fig. 18D). Ovipositor on average two thirds of body length; relatively straight and only lightly recurved upwards near the apex. Lower valve of ovipositor with 6 to 7 teeth below at the apex. Dorsal surface of upper valve heavily serrated in distal half (Fig. 18E–F).
Distribution and habitat
Isoplectron maculatum sp. nov. is currently only known from the alpine regions on Mt Peel in South Canterbury. It is most likely more widely distributed in the mountain ranges south of the Rangitata River, possibly as far west as the Two Thumb Range. Found almost exclusively on rock, where it feeds on lichen, it camouflages well with its background.
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 44-46, DOI: 10.5852/ejt.2024.971.2761, http://zenodo.org/record/14451786