Austronemobius chelatus, Hegg, 2024

Hegg, Danilo, 2024, Small crickets of New Zealand (Orthoptera: Grylloidea: Trigonidiidae and Mogoplistidae), with the description of two new genera and species, European Journal of Taxonomy 955 (1), pp. 1-87 : 36-40

Austronemobius chelatus gen. et sp. nov.

urn:lsid:zoobank.org:act:98D85C82-8E3A-4B1B-B2E0-41EEBB69B3DF

Figs 17–19 , 22A–B , 38D

Diagnosis

Refer to the above diagnosis for the genus.

Etymology

From the Latin ‘ chēla, chēlae ’, the arms of the constellation Scorpio, after the articulated pseudepiphallic parameres in the cricket’s male genitalia. Chelatus is used as an adjective. The species has been gifted the common name ‘Tarakihi Kahurangi’ by the local iwi Ngati Waewae.

Material examined (see also Supp. file 1: Table S4 )

Holotype

NEW ZEALAND • ♂, adult; Nelson (NN), Kahurangi National Park, Heaphy River; 40.94927° S, 172.14033° E; 40 m a.s.l.; 21 Feb. 2023; Department of Conservation leg.; in leaf litter on forest floor; jar; NZAC 03037179 .

Paratypes

NEW ZEALAND • 1 ♀, adult; Buller (BR), Lake Christabel Hut ; 42.43696° S, 172.25594° E; 680 m a.s.l.; 4 Jan. 2023; D. Hegg leg.; in beech leaf litter; jar; NZAC 03037180 • 1 ♂, 4 ♀♀; same data as for holotype; NZAC 03037182 to 03037186 .

Other material

NEW ZEALAND – Westland (WD) • 2 ♀♀; Kellys Creek, Ōtira River ; 42.80101° S, 171.57103° E; 360 m a.s.l.; 8 Apr. 2019; W. Fox leg.; pitfall trap; iNaturalist 24558958 . – Buller (BR) • 1 ♂; Camp Creek Hut ; 42.70600° S, 171.56134° E; 760 m a.s.l.; 19 Feb. 2023; D. Hegg leg.; in hut’s fire bath; jar; MPN OR0189 • 1 ♂; Bullock Creek, Punakaiki ; 42.09341° S, 171.38956° E; 100 m a.s.l.; 28 Jan. 2022; D. Lamont leg.; photograph only; iNaturalist 111192612 • 1 ♂; Lake Christabel outlet; 42.40342° S, 172.22788° E; 660 m a.s.l.; 5 Jan. 2023; D. Hegg leg.; in beech leaf litter; jar; MPN OR0188 • 1 ♂; Lewis Pass ; 42.37957° S, 172.40177° E; 860 m a.s.l.; 1 Feb. 2022; M. Bowie leg.; photograph only; iNaturalist 110563700 • 1 ♀; Black Hill, St Arnaud ; 41.79774° S, 172.83513° E; 740 m a.s.l.; 9 Apr. 2022; O. Dove leg.; photograph only; iNaturalist 117424945 • 1 ♂; Black Hill, St Arnaud ; 41.79989° S, 172.83631° E; 700 m a.s.l.; 13 Jan. 2024; D. Hegg leg.; in moss on forest floor; jar; MPN OR0190 . – Marlborough / Nelson (MB / NN) • 1 ♀; Red Hills Hut, Richmond Range ; 41.73080° S, 172.99098° E; 900 m a.s.l.; 20 Dec. 2012; M. Thorsen leg.; photograph only; iNaturalist 18226726. – Nelson (NN) • 1 ♀; Porters Creek Hut, Richmond Range ; 41.65332° S, 172.99737° E; 900 m a.s.l.; 3 Jan. 2022; D. Hegg leg.; in sparse, tall grass; insect net; MPN OR0448 • 1 ♂; Wangapeka Biv ; 41.37988° S, 172.27673° E; 580 m a.s.l.; 27 Jan. 2023; O. Dove leg.; photograph only; iNaturalist 148354097 • 1 ♀; Scotts Beach ; 41.09349° S, 172.10517° E; 30 m a.s.l.; Dec. 2022; J. Williams leg.; pitfall trap; NZAC 03037181 . – Taupō (TO) • 1 ♀; Mangawhero Forest Walk, Ohakune ; 39.39937° S, 175.41610° E; 620 m a.s.l.; 16 Feb. 2024; S. Trewick leg.; in leaf litter; MPN OR0494 .

Description

MASUREMENTS. See Table 4 . No sexual dimorphism.

HEAD ( Fig. 18A–B ). Width and height subequal in frontal view. Compound eyes large and bulging; measuring half of head height in their longest dimension. Ocelli present. Head colour a dark chestnut brown throughout, except for pale labrum and pale patches either side of rostrum. Stout bristles on vertex and on frons above and on sides of rostrum. Soft, pale setae around upper and lateral edges of labrum. Antennae: scapes yellow, flagelli pale brown. Maxillari palps pale and sparsely hairy, except for terminal segment, which is dark brown and covered in short, dense hairs.

THORAX ( Fig. 18C ). Pronotum 25% wider than long, widest at centre, narrowest at anterior and posterior edges. Colour uniform chestnut brown. Cuticle heavily textured, with three smooth protuberances either side of median line. Strong bristles on lateral lobes and on anterior and posterior edges.

WINGS. Forewings and hindwings absent.

LEGS. Fore and middle legs uniform yellow-brown; posterior legs variegated pale and brown. Femur I with sparse, strong bristles. Tibia I only with sparse bristles on dorsal and ventral surfaces; bearing two ventral spurs at apex, posterior spur only one third of length of anterior one. Auditory tympana absent. Tarsomere I-1 bearing two rows of short spinules ventrally. Femur II and Tibia II each with three pairs of strong bristles dorsally, one to two pairs ventrally. Tibia II bearing two long spurs at apex, subequal in length. Tarsomere II-1 bearing two rows of short spinules ventrally. Femur III glabrous and mostly of uniform colour inside; covered in hair outside, especially on dorsal surface. Femur III outer surface alternating yellow and brown diagonal stripes in proximal half; uniform brown in distal half. Tibia III armed with three pairs of subapical spurs dorsally, alternate. All apical and subapical spurs pale at base and at apex, brown in between; glabrous. Tibia III inner apical spurs 2 and 3 each covered by a row of setae facing one another, giving these spurs a feathered look. Length of outer ventral apical spur on Tibia III 85% to 90% of inner ventral apical spur length. Length of outer apical spur on Tarsomere III-1 80% of inner apical spur length.

ABDOMEN ( Fig. 17 ). Uniform chestnut brown in colour, except for some very faint pale markings on lateral edges of dorsal surface. Dorsum covered in sparse, thin tomentum throughout.

MALE TERMINALIA ( FigS 18D–F , 19 ). Subgenital plate trapezoidal, covered in long, sparse tomentum. Median lobe of pseudepiphallic sclerite protruding beyond suranal plate; visible in dorsal view. Pseudepiphallic parameres articulated, modified for clasping, protruding beyond posterior edge of subgenital plate and visible in dorsal and in ventral view.

FEMALE TERMINALIA ( Fig. 18H–I ). Subgenital plate trapezoidal. Ovipositor 40% to 50% of body length; enlarged near apex. Lateral valves dotted with numerous small tubercles at apex.

EGGS ( Fig. 18G ). Yellow; approx. 2 mm long and 550 µm wide.

Distribution

The species is only known from native forests in the north-west of New Zealand’s South Island, from sea level to tree-line, and from Mt Ruapehu in the central North Island ( Fig. 38D ). No other forest crickets are known in these regions.

Figures

Fig. 17. Austronemobius chelatus gen. et sp. nov., holotype, adult ♂, Heaphy River, Kahurangi National Park (NZAC 03037179), dorsal view. Scale bar = 2 mm.

Fig. 18. Austronemobius chelatus gen. et sp. nov. A–B. Lateral and frontal views of head, adult ♂. A. Heaphy River, Kahurangi National Park (NZAC03037182). B. Lake Christabel (MPN OR0188). C. Dorsal view of pronotum, adult ♂. Heaphy River (NZAC 03037179). D–F. External male terminalia. D. Dorsal view, with pseudepiphallic parameres (PsP) open (NZAC 03037179). E. Dorsal view, with pseudepiphallic parameres (PsP) closed (NZAC03037182). F. Ventral view. Heaphy River (NZAC 03037179). G. Egg. Heaphy River (NZAC03037186). H. Apex of ovipositor, dorsal view. Heaphy River (NZAC03037183). I. Ovipositor, lateral view. Heaphy River (NZAC03037184). Scale bars = 500 μm.

Fig. 19. Austronemobius chelatus gen. et sp. nov., ♂ genitalia. A. Microscope image of pseudepiphallic sclerite, dorsal view. Heaphy River, Kahurangi National Park (NZAC 03037182). B–F. Micro CT scans. St Arnaud, Nelson Lakes National Park (MPN OR0190). B. Ventral view. C. Longitudinal cross section, posterior-lateral view (45º angle). D. Longitudinal cross section, lateral view. E. Exterior, dorsal view. F. Exterior lateral view. Scale bars = 500 μm.

Fig. 22. Live silent Nemobiinae Saussure, 1877. A–B. Austronemobius chelatus gen. et sp. nov., photographed in its natural environment. A. Adult ♂, Heaphy River, Kahurangi National Park. B. Adult ♀, Lake Christabel. C–D. Mutonemobius marmoratus gen. et sp. nov., Awakino, Waikato. Photographed in captivity on unnatural background. C. Adult ♂. D. Adult ♀.

Fig. 38. Map of New Zealand, showing the known distribution of taxa included in this study. Thin black lines indicate the boundaries of Crosby’s entomological regions (Crosby et al. 1998; Fig. 2). Coloured circles indicate the collection localities for the material examined.