Boreoheptagyia ambigua Makarchenko, Wu et Wang, 2008

Makarchenko, Eugenyi A., Endo, Kazuo, Wu, Jingyang & Wang, Xinhua, 2008, A review of Boreoheptagyia Brundin, 1966 (Chironomidae: Diamesinae) from East Asia and bordering territories, with the description of five new species, Zootaxa 1817 (1), pp. 1-17 : 4-6

Boreoheptagyia ambigua Makarchenko, Wu et Wang , sp. n.

( Figs 7–10 )

Type material. Holotype male, CHINA: Sichuan Province, Kangding County, Wasi Gully , 15.vi.1996, light trap, X. Wang ( BDN).

Etymology. From Latin ambigua , meaning ambiguous or obscure, as the systematic position of this species in Boreoheptagyia is unclear.

Diagnostic characters. B. ambigua sp. n. is described based on a single male only and is closely related to B. xinglongiensis sp. n. Both species have dorsocentrals only in single anterior group. B. ambigua sp. n., however, can easily be separated from the latter by the shape of the gonostylus with wide median part and a short narrow apical part, and by the aedeagal lobe having some small teeth on the inner edge.

Male (n = 1)

Total length 2.4 mm. Wing length 1.64 mm. Total length / wing length 1.45.

Coloration. Head, thorax and abdomen brown. Antenna and legs yellowish; femur and tibia of all legs with rings, basal and apical parts light brown, median part white ( Fig. 9 ).

Head. Frontal tubercles damaged. Temporal setae includes 25 frontals, 12 outer verticals, no inner verticals. Clypeus with 9 setae. Antenna with 13 flagellomeres, antennal plume reduced, ultimate flagellomere with some large white spots ( Fig. 10 ); pedicel with 3 setae. Lengths (in µm) of flagellomeres 2–13: 24, 24, 40, 46, 50, 46, 42, 42, 40, 40, 32, 72. Number of setae on flagellomeres 2–13 as: 3, 3, 5, 5, 4, 4, 4, 3, 3, 4, 4, 3. Subapical seta of terminal flagellomere 23 µm long. AR 0.15. Lengths (in µm) of palpomeres 1–5: 30, 44, 72, 86, 160. Head width / palp length 1.16.

Thorax. Antepronotum with 6 lateral setae. Acrostichals 30; dorsocentrals 5, in single anterior group; prealars 12; scutellars 21. Longest and shortest acrostichals 76 µm and 27 µm long.

Wing. Costal extension 80 µm long. Anal lobe well developed, fully fringed. Alula without setae. Squama with 20 setae. R with 13 setae, R 1 with 2 setae, R 4+5 with 2 setae, R 2+3 reduced. RM/MCu 2.67.

Legs. Spur of foretibia 32 µm long; spurs of midtibia 32 µm and 34 µm long; of hind tibia 30 µm and 48 µm long. Hind tibial comb with 13 setae. Mid ta 1 with 4 pseudospurs, ta 2 with 2 pseudospurs, 23 µm long; hind ta 1 with 4 pseudospurs, ta 2 with 2 pseudospurs, 27 µm long. Lengths and proportions of legs as in Table 2.

Hypopygium ( Figs 7–8 ). Tergite IX with 11 setae, 104 µm long. Laterosternite IX with 4 setae. Transverse sternapodeme 56 µm wide. Aedeagal lobe weakly sclerotized, apical part smooth, inner edge with some small teeth ( Fig. 8 ). Gonocoxite 196 µm long. Gonostylus 94 µm long, with wide median part and short narrow apical part, ending in short megaseta. HR 2.09.

Distribution. The species is known only from the type locality in Sichuan Province in Oriental China.

Figures

FIGURES 7–13. Boreoheptagyia ambigua Makarchenko, Wu et Wang, sp. n. (7–10) and B. xinglongiensis Makarchenko, Wu et Wang, sp. n. (11–13), males. 7, 12. Hypopygium, dorsal view. 8. Distal part of aedeagal lobe. 9, 13. Legs. 10. Antennal flagellomeres 12–13. 11. Gonostylus. Scale bars: Figs 7, 10–13 = 50 µm, Fig. 8 = 20 µm.