Pleioplectron caudatum, Hegg & Morgan-Richards & Trewick, 2019

Hegg, Danilo, Morgan-Richards, Mary & Trewick, Steven A., 2019, Diversity and distribution of Pleioplectron Hutton cave wētā (Orthoptera: Rhaphidophoridae: Macropathinae), with the synonymy of Weta Chopard and the description of seven new species, European Journal of Taxonomy 577, pp. 1-46 : 28-30

Pleioplectron caudatum sp. nov.

urn:lsid:zoobank.org:act:7ADDB012-690F-4A3F-83F9-FDC54F8F9EED

Figs 2 A–B, 6H, 7G, 9D–F, 11D–F, 12C, 15C, 18G

Diagnosis

A small inhabitant of the forest floor in the southwestern regions of the South Island of New Zealand. The habitus is typical of Pleioplectron , chequered grey-brown in colour, with banded legs but overall dark and without a median dorsal line. At the northern end of its distribution range, it could easily be mistaken for P. gubernator sp. nov, which lacks the prominent ‘tail stump’. An examination of the adult terminalia is required to reliably distinguish these two species (compare Fig. 9 D–F with 9A–C). Around Haast Pass, P. caudatum sp. nov. is sympatric and shares the same microhabitat with P. flavicorne sp. nov. The latter is of a lighter brown colour, has bright yellow scapes on the antennae and lacks the ‘tail stump’.

Etymology

ʻ Caudatum ʼ is Latin for ‘tailed’, because of the protuberance on the last tergite in both sexes, which resembles a tail stump ( Figs 9E , 12C ).

Material examined (see also Table 8 in Supplementary Material)

Holotype

NEW ZEALAND • ♂, adult; Westland (WD), Haast Pass, Brewster Hut Track; 44.08062° S, 169.39055° E; 700 m a.s.l.; 25 Nov. 2017; Danilo Hegg leg.; on forest floor; night search + insect net; NMNZ AI.037486 (prev. MPN CW4053 ).

Paratype

NEW ZEALAND • ♀, adult; same collection data as for holotype; NMNZ AI.037487 (prev. MPN CW4040 ) .

Other material

NEW ZEALAND – Westland (WD) • 1 nymph; Haast Pass, Brewster Hut Track ; 44.08062° S, 169.39055° E; 700 m a.s.l.; 17 Feb. 2017; D. Hegg leg.; on forest floor; night search + insect net; MNP CW3443 • 2 ♂♂; same collection data as for holotype; MNP CW4049 , CW4052 • 1 ♂, 1 nymph; Lake Moeraki, Monro Beach Walk ; 43.70461° S, 169.26677° E; 20 m a.s.l.; 15 Oct. 2018; D. Hegg leg.; on small tree in lowland forest; night search + insect net; MNP CW4121 , CW4138 • 1 ♂; Franz Josef Glacier, Tatare Tunnel Track ; 43.38668° S, 170.1928° E; 200 m a.s.l.; 17 Oct. 2018; D. Hegg leg.; under bent tree trunk; night search + insect net; MNP CW4135 • 1 ♂; Moeraki River, Blowfly Hut ; 43.79108° S, 169.34630° E; 120 m a.s.l.; 13 Dec. 2018; D. Hegg leg.; on forest floor; night search + insect net; MNP CW4239 .

Description

MEASUREMENTS. See Table 1.

HEAD. Frons dark brown, with very sparse setae; vertex glabrous and of variegated colour. Eyes dark and bulging. Fastigium dark, with a white spot on either side. Scapes and peduncles pale and pilose; antennae dark brown, covered in fine setae. Maxillari and labial palpi light brown, with fine tomentum. THORAX. Pronotum variegated brown, mainly dark, with a few pale patches; dark with pale bars next to posterior margin; covered in sparse, fine tomentum. Anterior and lateral margins slightly rounded; posterior margin nearly straight.

LEGS. Moderately long; hind femora of approximately equal length as body; hind tibiae on average 20% longer than body in both males and females. Coxae and trochanters mottled light and dark brown. Fore and mid femora and tibiae with alternating conspicuous light and dark bands; hind legs variegated. Fore coxae with a pronounced lateral spine. Fore femora without linear spines above or below; armed with one prolateral spine at apex. Fore tibiae armed below, generally with one (at most two) linear spines on anterior edge, two linear spines on posterior edge. Fore tibiae armed with two long spines below (one prolateral and one retrolateral) and two short spines above (one prolateral and one retrolateral) at apex. Mid femora without linear spines above or below, but armed with one prolateral and one retrolateral spine at apex. Mid tibiae with two linear spines below on both anterior and posterior edge. Mid tibiae armed with two long spines below (one prolateral and one retrolateral) and two short spines above (one prolateral and one retrolateral) at apex. Hind femora unarmed below, but have one retrolateral apical spine. Hind tibiae with 25 to 30 linear spines above, of varying length, on both anterior and posterior edges. Hind tibiae with two superior subapical spines (one prolateral and one retrolateral), two superior apical spines (one prolateral and one retrolateral) and two inferior apical spines (one prolateral and one retrolateral). Superior subapical spines and inferior apical spines of approximately equal length, superior apical spines two to three times as long. Hind tarsi with four segments, first and second segment with a pair of spines on distal end. First segment with 5–8 small dorsal, alternate spines. Second segment with 2–3 small dorsal, alternate spines. Second and fourth segments one third of length of first segment, third segment one third of length of second and fourth segments.

ABDOMEN. Colour variegated brown, very dark with black patches and covered in sparse, fine tomentum. Dorsal median line absent.

MALE TERMINALIA. Cerci long, pointed at apex, dark brown in colour, clothed in setae. Styli short, rounded and not visible from above. Subgenital plate short, broadly oval, with median indentation ( Fig. 9D ). Last tergite with a distinctive protuberance, resembling a tail stump, that gives this species its name. Folds at base of cerci also pointed on interior edge, giving terminalia shape of a trident when seen from above ( Fig. 9E ).

FEMALE TERMINALIA. Subgenital plate broad and rounded ( Fig. 11D ). Ovipositor reddish brown, weakly recurved above at tip and relatively short (approximately 60% of body length). Upper valve smooth above, but lower valve with 9 shallow teeth on ventral edge at apex ( Fig. 11 E–F). Terminalia with a strong protuberance on last tergite when viewed from above, unique to this species ( Fig. 12C ).

Figures

Fig. 2. Phylogenetic relationships of Pleioplectron Hutton, 1896 cave wētā based on mtDNA sequence. A. Bayesian analysis using a mtDNA sequence alignment of 1429 bp spanning the majority of COI, with a minimum individual sequence length of 1330. Posterior probabilities are shown by nodes. B. Maximum Likelihood tree using PhyML with a COI alignment that contained sequences ranging from 483bp to 1429 bp, although the majority were>850 bp at the 3′ end of the gene. C. Map of New Zealand entomological (Crosby) regions. These codes are indicated in the Material examined section for each species.

Fig. 9. Adult male terminalia of cave wētā in the genus Pleioplectron Hutton, 1896. Left column: ventral view (subgenital plate); central column: dorsal view; right column: lateral view. A–C. P. gubernator sp. nov., Lewis Pass. A. MPN CW4063. B. MPN CW4067 C. MPN CW4059. D–F. P. caudatum sp. nov., Brewster Hut Track, Haast Pass (MPN CW4053). G–I. P. flavicorne sp. nov., Brewster Hut Track, Haast Pass (MPN CW4055). J–L. P. crystallae sp. nov., Cave Brook, Gouland Downs, Heaphy Track. J. MPN CW3994. K–L. MPN CW3995. M–O. P. rodmorrisi sp. nov., Kahutara Saddle, Seaward Kaikōura Range. M. MPN CW3536. N–O. MPN CW3395. Scale bars = 1 mm.

Fig. 12. Adult female terminalia of cave wētā in the genus Pleioplectron Hutton, 1896, dorsal view (suranal plate). A. P. simplex Hutton, 1896, Hinewai Reserve, Banks Peninsula (MPN CW4114). B. P. crystallae sp. nov., Salisbury Lodge, Mt Arthur (MPN CW3941). C. P. caudatum sp. nov., Brewster Hut Track, Haast Pass (MPN CW4040). Scale bars = 1 mm.

Fig. 11. Adult female terminalia of cave wētā in the genus Pleioplectron Hutton, 1896. Left column: subgenital plate; central and right columns: ovipositor. A–C. P. gubernator sp. nov. A. Awapoto Hut, Abel Tasman NP (MPN CW4057). B–C. Lewis Pass (MPN CW4071). D–F. P. caudatum sp. nov., Brewster Hut Track, Haast Pass (MPN CW4040). G–I. P. flavicorne sp. nov., Brewster Hut Track, Haast Pass (MPN CW4042). J–L. P. crystallae sp. nov., Cave Brook, Gouland Downs, Heaphy Track. J. MPN CW3993. K–L. MPN CW3990. M–O. P. rodmorrisi sp. nov., Hodder River, Inland Kaikōura Range (MPN CW3822). Scale bars = 1 mm.