Praecantrix silvatica silvatica

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, European Journal of Taxonomy 971, pp. 1-75 : 58-59

Praecantrix silvatica silvatica gen., sp. et subsp. nov.

urn:lsid:zoobank.org:act:94CE2C17-C99C-4E92-8870-F3494E224A98

Figs 3 , 9 , 10B , 11C–D , 12J , 16D–F , 19D–F , 23E

Diagnosis

Praecantrix silvatica silvatica gen., sp. et subsp. nov. is very similar to the sister subspecies Praecantrix s. lutea gen., sp. et subsp. nov., from which it is only differentiated by the overall darker coloration of the tergites, and by the longer ovipositor. The two subspecies are allopatric.

Etymology

The Latin adjective ‘ silvātĭcus ’ means ‘of or belonging to a wood or to trees’. The insect is exclusively a forest dweller.

Material examined (see also Supp. file 1: Table S10)

Holotype

NEW ZEALAND • ♂, adult; Nelson (NN), Mt Arthur Tablelands ; 41.18506° S, 172.64476° E; 1170 m a.s.l.; 24 Dec. 2020; D. Hegg leg.; on tree trunk in native forest; night search + insect net; NMNZ AI.071900.

Paratype

NEW ZEALAND • 1 ♀, adult; Westland (WD), Smoothwater Bay; 43.97494° S, 168.59452° E; 0 m a.s.l.; 14 Oct. 2018; D. Hegg leg.; on tree trunk in native forest; night search + insect net; NMNZ AI.071901 .

Other material

NEW ZEALAND – Otago Lakes (OL) • 1 ♀; Aspiring Hut, Matukituki Valley ; 44.47580° S, 168.65914° E; 460 m a.s.l.; 6 May 2017; D. Hegg leg.; on tree trunk in native forest; night search + insect net; GenBank: PP155094; MPN CW3518 . – North Canterbury (NC) • 1 ♀; Casey Hut, Poulter River ; 42.89625° S, 171.87076° E; 600 m a.s.l.; 1 Oct. 2021; D. Hegg leg.; on tree trunk in native forest; night search + insect net; MPN CW5388 . – Buller (BR) • 1 ♀; Nina Valley, Lewis Pass ; 42.46093° S, 172.34196° E; 680 m a.s.l.; 26 Jan. 2018; D. Hegg leg.; leaf litter in beech forest; night search + insect net; GenBank: PP155095; MPN CW3777 • 1 ♂; Cannibal Gorge, Lewis Pass ; 42.33964° S, 172.42218° E; 820 m a.s.l.; 25 Apr. 2017; D. Hegg leg.; in native forest; night search + insect net; GenBank: PP155091; MPN CW3453 • 1 ♀; Ces Clarke Hut, Paparoa Range ; 42.29007° S, 171.39307° E; 900 m a.s.l.; 6 Apr. 2019; D. Hegg leg.; on tree trunk in native forest; night search + insect net; MPN CW4945 . – Nelson (NN) • 1 ♂; Denniston Plateau ; 41.73792° S, 171.78861° E; 570 m a.s.l.; 8 Jul. 2012; M. Morgan-Richards and S. Trewick leg.; bioblitz; GenBank: PP155092; MPN CW1767 • 1 ♂; Mt Arthur Hut ; 41.19771° S, 172.71606° E; 1280 m a.s.l.; 21 Dec. 2020; D. Hegg leg.; on tree trunk in native forest; night search + insect net; GenBank: PP155093; MPN CW5390 • 1 ♂; Mt Arthur Tablelands ; 41.18500° S, 172.64370° E; 1170 m a.s.l.; 9 Feb. 2018; D. Hegg leg.; on tree branch in native forest; night search + insect net; GenBank: PP155096; MPN CW3766 • 1 ♀; same data as for preceding; MPN CW4000 • 1 ♀; same data as for holotype; GenBank: PP155097; MPN CW5391 • 1 ♀; same data as for holotype; CW5392 • 1 ♂; Chaffey Hut, Cobb River ; 41.09600° S, 172.57535° E; 880 m a.s.l.; 27 Dec. 2020; D. Hegg leg.; on tree trunk in native forest; night search + insect net; MPN CW5389 . – Marlborough (MB) • 1 ♂; Richmond Saddle ; 41.47924° S, 173.38111° E; 1200 m a.s.l.; 20 Oct. 2018; D. Hegg leg.; hopping on forest floor; night search + insect net; GenBank: PP155098; MPN CW4136 .

Description

MEASUREMENTS. See Table 1. Sexual dimorphism in body length, with females being larger by 1.5 mm (15%).

HEAD ( Fig. 11C–D ). Vertex pale with an elongated black patch in the middle and four dark stripes running from the eyes to the anterior margin of the pronotum, the two external stripes being thicker. Eyes black. Frons, clypeus and labrum pale, with two faint vertical dark stripes below the scapes of the antennae. Scapes and pedicels pale; flagellum variegated reddish-brown.

THORAX. Pronotum, mesonotum and metanotum glabrous and shiny, black on the sides, reddish-brown in the middle ( Fig. 12J ). Crisp line delimitating the dark upper parts from the white sternites.

LEGS. Rather short in both sexes. Sexual dimorphism present. The hind tibiae are about three quarters of body length in both males and females. Since females are larger than males, their hind tibiae are also longer, by approximately the same amount. Fore femora always unarmed at the apex. Mid femora armed with one retrolateral spine at the apex; prolateral apical spine absent. Hind femora armed with up to one prolateral and up to two retrolateral ventral linear spines, the retrolateral ones being larger. Fore tibiae armed with one or 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 usually absent. Mid tibiae armed with one or 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 10 dorsal linear spines (min 7, max 13) on both the anterior and the posterior edge. 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. All tergites glabrous and shiny, black on the sides, reddish-brown in the middle ( Fig. 12J ). Sternites pale.

MALE TERMINALIA. Suranal plate trapezoidal, the posterior, shorter side concave ( Fig. 16D ). Subgenital plate pear-shaped; covered in sparse, thin tomentum on the sides only; with two obvious lobes at the apex, covered with short, stout bristles on the upper side ( Fig. 16E ). Cerci on average 20% of body length, covered in sparse, mostly short hair; conical in the basal half, tapering to a blunt tip in the distal half. Styli short and stumpy.

FEMALE TERMINALIA. Subgenital plate square, with two rounded lobes on the distal corners, covered with sparse hair at the apex ( Fig. 19D ). Ovipositor approximately 65% of body length; moderately recurved upwards from the base to the apex; lower valve with 5 to 7 teeth below at the apex; dorsal surface of upper valve heavily serrated with strong teeth in distal third ( Fig. 19E–F ).

Distribution and habitat

Exclusively a forest insect, common and widespread in the western regions of New Zealand’s South Island, on both sides of the Main Divide of the Southern Alps, from Jackson Bay to Kahurangi National Park and to the Richmond Ranges ( Fig. 10B ).

Figures

Fig. 3. A. Phylogenetic relationships of six genera of New Zealand Rhaphidophoridae Walker, 1869 inferred from whole mitochondrial genome sequences using Maximum Likelihood approach and 1000 bootstraps. B. Map of New Zealand, showing locations of specimens of Isoplectron Hutton, 1896 and Praecantrix gen. nov. used in phylogenetic analyses (Figs 6–7). Colours correspond to different genera: red = Isoplectron; green = Praecantrix. Two letter codes indicate the New Zealand entomological regions (Crosby et al. 1998). These codes are reported in the Material examined section for each species.

Fig. 9. Gene tree for the two morphologically identified species of Praecantrix gen. nov. using Maximum Likelihood analysis of ~850 bp of mtDNA (COI) from 22 specimens. Node support labels are the result of 1000 ML bootstrap replicates.

Fig. 10. Known distribution of cave wētā in the genera Isoplectron Hutton, 1896 and Praecantrix gen. nov. A–C. All of New Zealand. A. Isoplectron armatum Hutton, 1896. Solid shapes indicate material collected as part of this study; empty circles indicate additional locations of material examined by Hutton (1896). Shapes represent different subspecies: circle = Isoplectron armatum armatum Hutton, 1896; diamond = Isoplectron armatum aciculatum Karny, 1937. B. Praecantrix silvatica gen. et sp. nov. Shapes represent different subspecies: dark green square = Praecantrix silvatica silvatica gen., sp. et subsp. nov.; light green diamond = Praecantrix silvatica lutea gen., sp. et subsp. nov. D. Map of North Island. E–J. Map of South Island. F. Isoplectron serratum (Richards, 1972) comb. nov. Solid shapes indicate material collected as part of this study; empty diamonds indicate additional locations of material examined by Richards (1972). Scale bars: 200 km.

Fig. 11. Head of cave wētā in the genera Isoplectron Hutton, 1896 and Praecantrix gen. nov., frontal and lateral views. A–B. Isoplectron armatum Hutton, 1896, adult ♂. Parsons Bush, Lake Ōhau (MPN CW5123). C–D. Praecantrix silvatica gen. et sp. nov., adult ♀. Mt Arthur Tablelands, Kahurangi National Park (MPN CW4000). Scale bars: 1 mm.

Fig. 12. Dorsal view of cave wētā in the genera Isoplectron Hutton, 1896 and Praecantrix gen. nov. A–I. Isoplectron. A. I. armatum armatum Hutton, 1896, adult ♂. Parsons Bush, Lake Ōhau (MPN CW5123). B. I. armatum aciculatum Karny, 1937, adult ♀. Ohakune (MPN CW5644). C. I. bicolor sp. nov., adult ♂. Mt Arthur Tablelands (MPN CW3760). D. I. serratum (Richards, 1972) comb. nov., adult ♂. The Gap, Torlesse Range (MPN CW3182). E. I. maculatum sp. nov., holotype, adult ♂. Middle Mt Peel, South Canterbury (NMNZ AI.071892). F. I. ferratum sp. nov., holotype, adult ♂. Cave Brook, Gouland Downs (NMNZ AI.071896). G. I. virgatum sp. nov., adult ♀. Cave Brook, Gouland Downs (MPN CW3794). H. I parallelum sp. nov., adult ♀. Ahumairangi Town Belt, Wellington (MPN CW5598). I. I. pallidum (Richards, 1972) comb. nov., adult ♂. Mt Kyeburn, Danseys Pass (MPN CW3456). J–L. Praecantrix. J. P. silvatica silvatica gen., sp. et subsp. nov., adult ♂. Mt Arthur Hut (MPN CW5390). K. P. silvatica lutea gen., sp. et subsp. nov., adult ♂. Peel Forest (MPN CW4968). L. P. saxicola gen et sp. nov., holotype, adult ♂. Mt Wakefield (NMNZ AI.071904). Scale bar: 10 mm.

Fig. 16. Adult male terminalia of cave wētā in the genera Isoplectron Hutton, 1896 and Praecantrix gen. nov. Left column: dorsal view; central column: ventral view (subgenital plate); right column: lateral view. A–C. Isoplectron parallelum sp. nov., holotype. Ahumairangi Town Belt, Wellington (NMNZ AI.071898). D–F. Praecantrix silvatica silvatica gen., sp. et subsp. nov. D, F. Holotype. Mt Arthur Tablelands, Kahurangi NP (NMNZ AI.071900). E. Richmond Saddle, Marlborough (MPN CW4136). G–I. Praecantrix silvatica lutea gen., sp. et subsp. nov., holotype. McLean Falls, Catlins Forest (NMNZ AI.071902). J–L. Praecantrix saxicola gen. et sp. nov., holotype. Mt Wakefield, Aoraki / Mt Cook NP (NMNZ AI.071904). Scale bars: 1 mm.

Fig. 19. Adult female terminalia of cave wētā in the genera Isoplectron Hutton, 1896 and Praecantrix gen.nov.Leftcolumn:subgenitalplate; centraland right columns:ovipositor.A–C. Isoplectronparallelum sp. nov., paratype. Ahumairangi Town Belt, Wellington (NMNZ AI.071899). D–F. Praecantrix silvatica silvatica gen., sp. et subsp. nov. D. Paratype. Smoothwater Bay, South Westland (NMNZ AI.071901). E–F. Aspiring Hut, Mt Aspiring NP (MPN CW3518). G–I. Praecantrix silvatica lutea gen., sp. et subsp. nov. G. Paratype. Ōpoho, Dunedin (NMNZ AI.071903). H–I. McLean Falls, Catlins (MPN CW4946). J–L. Praecantrix saxicola gen.et sp. nov., paratype. Mt St Bathans, Central Otago (NMNZ AI.071905). Scale bars: 1 mm.

Fig. 23. Live Isoplectron Hutton, 1896 and Praecantrix gen. nov. in their natural habitats. A. Isoplectron virgatum sp. nov., adult ♀ on Astelia Banks & Sol. ex R.Br. leaf. Bob’s Hut, Matakitaki River. B. Isoplectron ferratum sp. nov. in black beech Fuscospora solandri (Hook.f.) Heenan & Smissen tree canopy. Cave Brook, Gouland Downs, Kahurangi NP.C. Isoplectron parallelum sp. nov., adult ♀ on flax Phormium tenax J.R.Forst. & G.Forst. flower. Wellington. D. Praecantrix saxicola sp. nov., adult ♀. Mt St Bathans, Central Otago. E. Praecantrix silvatica silvatica gen., sp. et subsp. nov. adult ♀. Mt Arthur Tablelands, Kahurangi NP. F. Praecantrix silvatica lutea gen., sp. et subsp. nov. adult ♀. Hinau Track, Kaikōura.