Trichoclinocera systenognatha sp. nov.

Figs 1–4, 5–6, 9, 12–13, 14

Type material.

Holotype • ♂, labelled: “ (BHUTAN) / E of Dochhu / La [27°29'N 89°45'E], 2800 m / 16. viii. 1993 / T. Saigusa ”; “ HOLOTYPE / Trichoclinocera / systenognatha / Saigusa & Sinclair [red label] ” (KUMF). Paratypes: Bhutan: • Same data as holotype (2 ♂, 4 ♀, KUMF); • same data except, 20. viii. 1993 (2 ♂, 1 ♀, KUMF); • E of Jilay La [27°22'N, 89°22'E], 3000 m, 19. viii. 1993, T. Saigusa (1 ♂, CNC; 5 ♂, 9 ♀, KUMF); • W of Yutong La [27°31'N, 90°34'E], 3250 m, 15. viii. 1993, T. Saigusa (4 ♂, 2 ♀, CNC; 23 ♂, 35 ♀, KUMF). China: Yunnan: • Lijian, Heishuihe [27°09'N, 100°14'E], 2800–2900 m, Yulongxueshan, 15. vi. 1996, T. Saigusa (1 ♂, CNC; 7 ♂, 14 ♀, KUMF); • Dali, Daboping [25°34'N, 100°08'E], 1900–2200 m, 7 km W Xianguan, 16. viii. 1996, T. Saigusa (1 ♀, KUMF); • Yunglong, 3 km NNW of Zhichang [25°50'N, 99°02'E], 2500–2600 m, 5. vi. 1996, T. Saigusa (1 ♂, CNC; 1 ♂, 3 ♀, KUMF). Nepal: • Bagmati, Ghora Tobela [28°12'N, 85°27'E], Langtang, 3000–3400 m, 12. ix. 1983, M. Suwa (1 ♀, HUS); • Chiaksila [27°26'N, 86°57'E], 2800 m, 20. vii. 1981, J. Emoto (14 ♂, 28 ♀, KUMF); • same data except, 14. vii. 1981 (5 ♂, 1 ♀, CNC); • Dobang Kharka, 2400 m, 28°36'N, 83°24'E, 24. ix., 9–15. x. 1971, A. Nakanishi (3 ♂, KUMF); • Thurukpa, 2600 m, 27°36'N, 87°36'E – Topke Gola, 3700 m, 27°38'N, 87°35'E, 12. vi. 1972, J. Emoto (1 ♂, CNC; 1 ♂, KUMF); • NE of Thudam, 4000 m, 27°47'N, 87°36'E, 25. vi. 1972, H. Shima (6 ♂, 9 ♀, KUMF); • Topke Gola, 3700 m, 27°38'N, 87°35'E, 13. vi. 1972, H. Shima (1 ♂, KUMF); • Salpa La [27°27'N, 86°55'E], 2800–3000 m, 23. vii. 1981, J. Emoto (1 ♂, 2 ♀, KUMF); • same data except, 28. vii. 1981 (1 ♀, KUMF); • same data except, 29. vii. 1981 (1 ♂, 1 ♀, KUMF). Vietnam: • Sa Pa, 1500 m [22.361°N 103.778°E], Lao Cai Prov., 27. v. 1997, R. Matsumoto (1 ♂, KUMF); • same data except, 1700 m, 26. v. 1997 (1 ♀, KUMF).

Etymology.

The species name is derived from the Greek systenos (tapering to a point) and Greek gnathos (jaw), in reference to the pointed labellum of this species, which also characterizes this group of species.

Diagnosis.

This species is distinguished from the other two species of this species subgroup by one (rarely two) stout anterior subapical seta (e) on the fore femur (Figs 3, 4) and males with a much shortened and stouter hypandrium (Figs 9, 12) and lacking stout posteroventral setae on the apical fourth of the fore femur (Fig. 3).

Description.

Wing length (n = 5): 4.7–5.3 mm. Male. Bright blue pruinescence laterally, with dark brown vertex of head and scutum (Fig. 5). Head rounded; compound eyes large, rounded (Figs 1, 2). Face convex, narrowest at middle, ca. 1.3 × width of antennal sockets, entirely clothed in bright whitish blue pruinescence; lower margin of face with slight cleft with small carina or swelling; gena one-fourth as wide as height of eye. Vertex and ocellar triangle dark brown, lower postocciput and gena lightly pruinescent. Ocellar setae longest among cranial setae; occiput with pair of setae posterior to ocellar triangle; above ‘ neck’ row or crown of supracervical setae, setae in middle longest, decreasing in length laterally; postocular with row of short setae along margin of eye, upper 4–6 setae dark, stouter than lower setae. Arista stout, shorter than width of eye; slightly tapered apically. Palpus cylindrical, length less than one-third height of eye; labellum with ventral triangular projection.

Pleura and lateral margin of scutum, including postpronotal lobe, extending medially toward first dc and notopleuron with bright blue pruinescence; scutellum, postalar ridge and region medial to postalar light brown. Thoracic setae shorter than width of eye; several acr anterior to first dc; 5 pairs dc; 1 slender, short pprn, one-half length of dc; 1 slender presut spal; 2 npl; 2 psut spal; 1 pal; 1 pair sctl and several pale marginal setulae; several pale setulae on postpronotal lobe and notopleural depression. Laterotergite with patch of pale setae; proepisternum, posteromedial margin of katepisternum and hind margin of metepisternum with long pale setulae.

Wing (Fig. 6) narrow, infuscate; narrow, faint, elliptical pterostigma present. One basal costal seta, two-thirds length of posterior dc. Row of setulae from base of R to just beyond origin of Rs; cell dm produced apically; R 4 + 5 slightly curved; R 4 and R 5 divergent throughout. Halter knob dark with base of shaft orange-brown.

Legs dark greyish brown, except coxae with blue pruinescence concolourous with pleura. Coxae with long pale marginal setae; anterior face of fore coxae with scattered pale setae, outer basal not longer than other setae. Fore femur with 1 (rarely 2) stout, black anterior subapical seta (e), shorter than width of femur; anteroventral margin with row of very short, stout, black setae, increasing in length apically, ca. one-sixth width of femur (Fig. 3); basal half with posteroventral row of slender, pale setae, slightly shorter than width of femur, without stout posteroventral setae on the apical fourth. Fore tibia with biserial row of short, erect setae beneath, ca. one-half width of tibia. Foreleg tarsomeres lacking white ventral pubescence. Mid and hind femora with row of long, erect anterior setae, slightly longer than width of femur. Mid and hind femora with 2–4 pairs of slender anteroventral and posteroventral preapical setae; anterodorsal and posterodorsal setae absent. Hind tibia generally lacking setae except for several erect, stout dorsal and ventral setae on apical fourth. Tarsi much shorter than corresponding tibiae; tarsomere 1 of all legs with long ventral seta at base. Empodium pulvilliform, slightly shorter than claw, more than one-half length of tarsomere.

Hypandrium broad, quadrate, distinctly longer than epandrium (less than 1.3 times); anterior margin with or without long slender apodeme (Fig. 9). Phallus extending beyond clasping cercus; gradually arched throughout; apical portion flattened in dry specimens; apex with flexible anterior sclerite, occasionally with long narrow membranous sac and longitudinal groove laterally (maybe expansion of inner sac due to clearing); ejaculatory apodeme large, arched strongly anteriorly. Surstylus small, much shorter than clasping cercus with pair of knob-like projections on anterior margin bearing setulae. Clasping cercus finger-like, gradually tapered to rounded apex; anteroventral margin with several setae, longer than width of cercus; inner face with short, peg-like setae especially on basal half.

Female. Similar to male except as follows: face blue pruinescent, brownish medially; chaetotaxy of fore femur reduced, with setae of anteroventral row shorter and less stout (Fig. 4); posteroventral setae slenderer, one-fifth width of femur; fore tibia lacking modified setae beneath. Terminalia (Fig. 13): sclerites closely approximated laterally; T 8 with posterior row of long setae, dorsal setae longer than length of sclerite in dorsal view; T 9 + 10 with curved setae on apical two-thirds, with 5 apical and several inner setae more stout than remaining setae; anteroventral corner of T 9 + 10 subtriangular, prolonged obliquely.

Distribution.

This species is known from eastern Bhutan, Nepal, Yunnan Province (China) and Vietnam (Fig. 14).

Remarks.

Some variation in the inner chaetotaxy of the clasping cercus was noted among various populations. Specimens from Nepal (Thudam) possessed very long spine-like setae, especially dense towards the apex, while in Yunnan there were mostly blunt spines, denser basally. In Nepal (Chiaksila) specimens, the spine-like setae were longer than among Yunnan specimens, but also concentrated basally.