Microchironomus tabarui Sasa

Yan, Chuncai & Wang, Xinhua, 2006, Microchironomus Kieffer from China (Diptera: Chironomidae), Zootaxa 1108, pp. 53-68 : 59-61

Microchironomus tabarui Sasa

( Fig. 3 A–E)

Microchironomus tabarui Sasa 1987: 63 ; Sasa 1988: 56

Material examined: Tianjin City, 3 males, 3. V. 1979, 20. VI. 1985, X. Wang; Hebei Province, Qinhuangdao City, 1 male, 4. VI. 1985, X. Wang; Jiangsu Province, Suzhou City, 3 males, VIII. 2003, X. Wang. Hubei Province, Wuhan University, 1 male, 29. X. 2003, sweep net, X. Wang; Guizhou Province, Libo County, 420 m, 1 male, 7. VIII. 1995, light trap, W. Bu.

Diagnostic characters: The species can be distinguished from others by the superior volsella with several long and short setae, and the anal point short, broadest basally, and often expanded and truncated apically.

Male imago (n = 9, unless otherwise stated)

Total length 3.13–4.70, 3.65 mm. Wing length 1.45–2.05, 1.68 mm. Total length/wing length 1.72–2.45, 2.19. Wing length/length of profemur 2.26–2.70, 2.41.

Coloration: Thorax dark brown to yellow green, femora and distal 1/3 of tibia of front leg yellowish green, remaining parts of front leg dark brown, mid and hind legs yellowish green, only tarsi 5 dark brown ( Fig. 3 A) or distal 1/3 of tarsi 1 and tarsi 2–5 dark brown ( Fig. 3 B). Abdomen yellowish green to brown.

Head: AR 1.96–2.56, 2.36. Ultimate flagellomere 530–700, 592 µm long. Frontal tubercles present, columnar, 10–13 (2) µm long, 7–10 (2) µm wide; or rounded, 4–5, 4 (4) µm in diameter. Temporal setae 6–12, 9; including 0–4, 2 inner verticals; 2–5, 4 outer verticals; and 3–6, 4 postorbitals. Clypeus with 11–20, 15 setae. Tentorium 120–155, 137 (6) µm long, 25–36, 30 (6) µm wide. Palpomere lengths (in µm): 32–48, 38; 37–58, 46; 93–120, 102; 100–165, 143; 180–220, 197; 150 µm long, 50 µm wide. Palpomere lengths (in µm): 37; 55; 188; 160; 178. Palp segment 5th/3rd 1.72–2.12, 1.95.

Thorax: Antepronotals 0–7, 4, acrostichals 0–9, 5, dorsocentrals 8–10, 9, prealars 2–4, 3. Scutellum with 3–9, 6 setae.

Wing ( Fig. 3 C): VR 1.08–1.16, 1.11, R with 0–6, 2 setae, R1 with 0–1, 0 setae, R4+5 with 2 setae at apex. Brachiolum with 2 setae. Squama with 12–28, 17 (5) setae.

Legs: Front tibia with 2 subapical setae, 75–100, 89 (8) and 65–87, 76 (5) µm long, spurs of middle tibia 16–24, 19 and 19–25, 22 µm long, comb with 23–32, 27 teeth, 8–10, 8 µm long; spurs of hind tibia 20–25, 23 and 25–30, 26 µm long, comb with 30–40, 35 teeth, 8–10, 10 µm long. Tarsus 1 of mid leg with sensilla chaetica 11–19, 15. Lengths (in µm) and proportions of legs as in Table 3 .

Hypopygium ( Fig. 3 D, E): Tergite IX with 7–10, 8 setae. Laterosternite IX with 2–5, 4 setae. Anal point 50–62, 54 µm long, 25–33, 29 µm wide at base, 18–25, 21 µm wide at apex, with 12–18, 14 setae beside ridge. Ninth tergite with pair of rounded processes on posterior margin flanking anal point, bearing 8–12, 10 setae and microtrichia. Superior volsella digitiform, 50–88, 66 µm long with 4 or 5, 5 setae apically and 4–12, 7 short setae. Anal tergite bands T shaped. Phallapodeme 55–98, 78 µm long. Transverse sternapodeme 35–63, 49 µm long. Gonocoxite 105–137, 121 µm long, with 3–5, 4 strong setae along inner margin. Gonostylus 183–225, 198 µm long with apical hook, inner margin expanded basally, and bearing 22–28, 24 setae in 2 rows along inner margin. HR 0.47–0.73, 0.62, HV 1.66–2.09, 1.84.

Distribution: The species was previously recorded from Japan (Palaearctic Region). It also was collected by sweep net and light trap from Palaearctic and Oriental China. The species is a new record for China.

Remarks: In the Chinese specimens, the middle of the anal point has a setose ridge.

Figures

FIGURE 3. Microchironomus tabarui Sasa, Chinese specimen. A, B, legs; a, front leg; b, mid leg; c, hind leg. C, wing. D, dorsal view of hypopygium. E, ventral view of hypopygium.

Tables

TABLE 3. Lengths (µm) and proportion of legs of Microchironomus tabarui Sasa, male (n = 9).

	fe	ti	ta1	ta2	ta3	ta4	ta5	LR
p1	620–850, 694	520–720, 577	650–890, 732	370–470, 419	300–380, 340	200–270, 234	90–160, 130	1.21–1.33, 1.27
p2	610–820, 693	530–750, 607	280–400, 329	150–210, 178	110–170, 138	80–130, 98	80–120, 91	0.49–0.63, 0.54
p3	670–900, 757	680–960, 787	430–600, 501	250–340, 291	220–300, 232	120–180, 153	100–170, 119	0.61–0.66, 0.64