Thienemannimyia dimorpha, Cheng, Ming & Wang, Xinhua, 2009

Cheng, Ming & Wang, Xinhua, 2009, Thienemannimyia Fittkau (Diptera: Chironomidae) from China, Zootaxa 2074, pp. 50-60 : 51-54

Thienemannimyia dimorpha sp. n.

( Figs 5–9 )

Type material. Holotype male, China: Yunnan Province, Lijiang County, Shigu Town, Chongjianghe River, 25.v.1996, light trap, B.X. Wang (BDN No. 10936). Paratypes: 3 males, same data as holotype (BDN No. 10891, 10892,10937); 7 males, China: Sichuan Province, Xiangcheng County, Shuoquhe River, 12.vi.1996, light trap, X.H. Wang (BDN No.13309, 13311, 13314,13316,13317, 13318, 13319); 1 male, China: Sichuan Province, Yajiang County, Snodaoqiao, 9.vi.1996, light trap, X.H. Wang (BDN No.01597).

Etymology. Named after the distinctive antenna of the male.

Diagnostic characters. The species closely resemble T. barberi in the colour of the abdomen, but it sometimes has the female-like antenna with 11 or 12 flagellomeres. Also it can be distinguished from T. barberi by the different wing markings and the shape of median volsella.

Description. Male (n = 12). Total length 2.73–3.43, 3.11 mm. Wing length 2.38–2.65, 2.50 mm. Total length / wing length 1.14–1.34, 1.24. Wing length / length of profemur 2.39–3.71, 2.61.

Colouration. Head including antenna brown. Thorax brown with darker vittae and anterior anepisternum II ( Fig. 7 ). Ground colour of abdomen yellow, tergites II–VIII each with a brown rounded mark in the middle and additional dark stripe along lateral margins ( Fig. 8 ). Legs light brown with brown band on femora. Wing markings as in fig. 6.

Head. Setae of the antennal flagellum reduced in number. Antenna with 11 ( Fig. 5 ) or 14 flagellomeres.

Nine specimens (no. 10891, 10892, 10936, 10937, 13314, 13316, 13317, 13318, 13319) with 11 flagellomeres, 10th flagellomere the longest, AR 0.35–0.45, 0.42. Three specimens (no.01597, 13309, 13311) with 14 flagellomeres, the 13th flagellomere the longest, AR 1.23–1.36, 1.29. Temporal setae 16, including 14 verticals and 2 postorbitals. Clypeus with 20–26, 22 setae. Tentorium 130–175, 148 µm long; 30–35, 31 µm wide. Length of palpomeres 1–5 (in µm): 50; 90–110, 100; 135–175, 154; 190–220, 204; 300–375, 328.

Wing ( Fig. 6 ). VR 0.88–0.95, 0.92. Brachiolum with 3 long setae. Squama with 26–32, 28 setae. Thorax chaetotaxy. Antepronotals 6; dorsocentrals 32–44, 40; acrostichals 52–62, 57; prealars 18–22, 20; preepisternals 3–4, 4; scutellars 38–52, 45.

Legs. Spur on fore tibia 30–50, 42 µm long with 8 lateral teeth. Spurs on mid tibia 53–65, 60 and 40–55, 47 µm long with 6 and 4 lateral teeth. Spurs on hind tibiae 65–88, 76 and 40–53, 49 µm long with 6 and 4 lateral teeth. Tibial comb on hind leg with 8 setae. Length of legs segments and leg ratios in Table 1 .

fe ti ta1 ta2 ta3 ta4 ta5 LR Hypopygium ( Fig. 9 ). Tergite IX concave, with 12–12 setae. Anal point absent. Gonocoxite 175–220, 197 µm long, cylindrical. Gonostylus 150–175, 163 µm long, slim. Megaseta 15µm. HR 1.15–1.42, 1.22. HV 1.72–2.18, 1.90.

Female, pupa and larva: unknown.

Remarks. The specimens from Xiangcheng County Sichuan province have both male-liked and femaleliked antennae. Although there is variation in the number and shape of flagellomeres, most of the other characters are identical. Therefore, we treat this as individual variation within the species.

The species was collected in a subtropical mountain area in Yunnan and Sichuan province in Oriental China.

Figures

FIGURES 5 – 9. Thienemannimyia dimorpha sp. n., male. 5 — female-like antenna; 6 — wing; 7 — thorax; 8 — abdomen; 9 — hypopygium, ventral and dorsal views.

Tables

TABLE 1. Length (μm) of leg segments and leg ratios of male Thienemannimyia dimorpha sp. n. (n = 12).

p1 875–1025, 960 1125–1325, 1218	875–1125, 1035450–600, 531	320–420, 371	220–290, 260	135–160, 145 0.73–0.92, 0.85
p2 1000–1125, 1025–1175, 1060 1102	620–690, 652 300–350, 321	230–260, 248	190–210, 203	110–130, 118 0.55–0.63, 0.59
p3 900–1000, 952 1225–1650, 1350	950–1075, 1006510–630, 566	380–460, 423	250–300, 275	120–160, 140 0.72–0.84, 0.76