Thienemanniella fuga Lehmann, 1979

Fu, Yue, Hestenes, Tor Christian & Saether, Ole, 2010, Review of Afrotropical Thienemanniella Kieffer (Diptera: Chironomidae: Orthocladiinae), Zootaxa 2338, pp. 1-22 : 8-11

Thienemanniella fuga Lehmann, 1979

( Figs 3 A–G)

Thienemanniella fuga Lehmann, 1979: 47 ; Harrison 1992: 193 [Key].

Material examined. DEMOCRATIC REPUBLIC OF THE CONGO: Kinsangani, 1 3, 16. iii. 1975, J. Lehmann. TANZANIA: Tanga province, West Usumbara Mountains, Mazumbai, Kaputu Stream, Station 7, 2 3, Malaise trap, 4–13. xii. 1990, ZMB `s Tanzania Expedition. SOUTH AFRICA: Transvaal, Lydenburg district, Waterval, Santa River, 2 males, 2 ƤƤ, iv–v. 1955, A. D. Harrison ( BMNH).

Diagnostic characters. The adult male has 8 flagellomeres sometimes with incomplete separation of the two ultimate segments. It is separable from the other Afrotropical species, except T. trivittata , by having a thin, anteriorly curved transverse sternapodeme. However, it differs from T. trivittata in having inferior volsella as a median lobe of the gonocoxite. The female can be separated from other Afrotropical species by having one anal vein and a well developed anal lobe on the wing. The ramus is narrow and elliptical.

Adult male as in Lehmann (1979) with the following additions (n = 3–4):

Total length 0.91–1.17 mm. Wing length 0.65–0.70 mm. Total length/wing length 1.40–1.67. Wing length/ length of profemur 3.15–3.31. Wing width/wing length 0.44–0.48.

Coloration. Head pale. Thorax with scutellum, upper antepronotum, upper scutum, preepisternum and anterior and median anepisternum II light brown; vittae pale. Abdomen with light brown to yellow tergites, sternites pale. Tergites VI and VII with median, pale field.

Head ( Figs 3 B–C). Eyes hairy, hairs relatively long, about 8 µm; height of eye/height of head 0.64–0.68. Antenna ( Fig. 3 C) with 8 flagellomeres, flagellomere 7 and 8 partly to fully separated. Ultimate flagellomere club-shaped with notched or rounded apex, maximum width 19–24 (2) µm, with 13–17 apical sensilla chaetica, no setae. AR 0.24–0.27. Tentorium, stipes and cibarial pump as in Fig. 46; tentorium 113–128 µm long, stipes 64–70 µm long. Palpomere lengths (in µm): 15–20, 11–14, 22–27, 40–50, 98–117 (2). Palpomere 5/3 5.0–5.4 (2), palpomere 3 ovoid, palpomere 4 broad and rectangular, palpomere 5 thin and slender. Single sensillum clavatum located subapically on lateral side. Clypeus with 8–9 setae. Verticals absent, coronals 4.

Thorax ( Fig. 3 D). Anapleural suture 93–104 (3) µm long. Antepronotals 1, dorsocentrals 8–9 uniserial, prealars 3, scutellars 1–2.

Wing ( Fig. 3 A). VR 1.47–1.57 (2). Wing wide, anal lobe very weak. One anal vein present, An1/wing length 0.51–0.60 (2); PCu/wing length 0.49 (2); C/wing length 0.32–0.33 (2); Cu/wing length 0.30–0.40. Brachiolum with 1 seta and apparently 3 sensilla campaniformes; C with 9–11 setae. Setation on remaining wing margin as for T. trivittata .

Legs. Fore trochanter with distinct dorsal keel. Spur of fore tibia 15–19 µm long, spurs of mid tibia 14–20 µm and 7–14 µm long. Hind tibia with curved seta 14–20 µm long, spurs 18–27 µm and 12–16 µm long. Width at apex of fore tibia 18–20 µm, of mid tibia 20–25 µm, of hind tibia (a) 26–28 µm. Width of hind tibia 1/3 from apex (d)19–20 µm, elongation (b)14–16 µm long, length of maximum thickening (c1) 25–34 µm, total length of thickening (c2) 47–61 µm, a/d 1.30–1.53, b/d 0.70–0.84, c1/d 1.32–1.70, c2/d 2.35–3.21. Hind tibial comb with 11–12 setae. Ta1–2 of p2 with apical sensilla chaetica ventrally. Ta1 of p3 with two ventral rows of 5 and 7 strong, short setae; ta2 with 1 ventral strong seta at 0.43 of length, and 1 strong seta apically; ta3 with 1 apical strong setae. Lengths (in µm) and proportions of legs as in Table 4.

Abdomen. Tergite I with 2 setae laterally on each side. Number of setae on tergites II–VIII: 3, 3, 2–3, 2, 2, 3, 1–2.

Hypopygium ( Fig. 3 E). Sternite VIII 1–2 setae; tergite IX with 2 small setae; latero-sternites IX without setae; tergite IX with a small, flexible, triangular hump-like extension. Gonocoxite IX with 3–4 large setae, all caudally, 5–6 smaller glandular setae ventrally. Superior volsella very narrow, anteromedially fused, posteriorly separated from inferior volsella. Inferior volsella small, subrectangular, with round corners, broadest posteriorly, carrying thin glandular setae. Tip of phallapodeme bent 90° caudally. No basal projections on phallapodeme, length 29 µm (2). Transverse sternapodeme slightly curved upwards as for T. trivittata , thin, 28–33 µm broad. Gonocoxite length 82–88 µm. Gonostylus slender, 25–32 µm long; megasetae stout, 7 µm long. HR 2.79–3.18, HV 3.47–4.41.

Adult female (n = 1–2)

Total length 0.83–0.98 mm. Wing length 0.69–0.72 mm. Total length/wing length 1.15–1.33. Wing length/ length of profemur 4.72–4.82. Color as for male except paler.

Head. Eyes hairy; eye hairs as for male. Height of eye/height of head 0.69. Antenna with 5 flagellomeres, flagellomere lengths (in µm): 26–27, 25–27, 27–29, 25–26, 50–52; AR 0.48 (2). Ultimate flagellomere with apical sensilla chaetica and no setae. Tentorium 133–139 µm long, stipes 91–116 µm long, maximum 7 µm wide. Palpomere lengths (in µm): 15–18, 9–11, 22–24, 27–37, 107–113. Palpomere 5/3 ratio 4.5–5.1. Palpomere 2 small, palpomere 3 round, palpomere 4 and 5 slender. Single sensillum clavatum placed subapically. Clypeus with 6 (2) setae. Verticals absent, coronals 4.

Thorax. Anapleural suture 76–91µm long, s/a 0.64. Antepronotals 0, dorsocentrals 9–10 uniserial, prealars 3, scutellars 0.

Wing ( Fig. 3 F). VR 1.47–1.57 (2). Wing shape as for male, but broad with one anal vein, An1/wing length 0.51–0.60 (2), PCu/wing length 0.49 (2), C/wing length 0.32–0.33 (2), Cu/wing length 0.30–0.40. Brachiolum with 1 seta and 3 apparently sensilla campaniformes, C with 17–20 uniserial setae. Setation on wing margin as for male.

Legs. Fore trochanter with distinct dorsal keel. Spur of fore tibia 16–20 µm long; spurs of mid tibia 11–20 µm and 14–23µm long; hind tibia with longest spur slightly S-shaped, simple, 16–23 µm long, and straight spur, 11–18 µm long. Width at apex of fore tibia 16–18 µm, of mid tibia 20–25 µm, of hind tibia (a) 25–27 µm. Width of hind tibia 1/3 from apex (d) 19–20 µm, elongation length (b) 14–16 µm, length of maximum thickening (c1) 25–34 µm, total length of thickening (c2) 47–61 µm; a/d 1.30–1.53; b/d 0.70–0.84; c1/d 1.32– 1.70; c2/d 2.35–3.21. Hind tibial comb of 11–12 setae. Single sensillum chaeticum placed apically on ta1–4 of p2. Ta1–4 of p1 with 1 strong apical seta ventrally. Ta1 of p3 with 1 ventral row of 6, and 1 lateral row of 8 strong short setae, ta2 with 2 ventral strong, short setae; ta 3 with 1 ventral strong short seta at 0.50 of length; ta1–4 all with 1 strong seta apically on ventral side. Ta4 of all legs cordiform. Lengths (in µm) and proportions of legs as in Table 5.

Abdomen. Tergite I with 2 setae in patch mediolaterally on each side. Number of setae of tergites II–VII: 1, 1, 1, 3, 3, 1. Sternite I and VIII without setae, sternite II–VII with 1 short seta medially.

Genitalia ( Fig. 3 G). Sternite VIII bare, tergite IX with 1 setae to each side at caudal margin, gonocoxite IX with 1 setae. Segment X large and rectangular. Coxosternapodeme straight, narrower than for T. trivittata . Gonocoxapodeme high (about 45 µm), slender, S-shaped. Cercus 27–35 µm long. Notum length 27 µm, ramus narrow and long, length of gonapophysis IX 97 µm. Seminal capsules 40–46 µm long, 20 µm wide. Postgenital lobe circular, covered with spine-like microtrichia, internally below it a large sac-like finely sclerotized bursa with projecting parts anterolaterally. Labia invisible. Gonapophysis VIII possible subdivided mesally, covered with fine hair-like microtrichia.

Distribution. The locality in Tanzania is a small stream located in moist mountainous rain forest. The substrate in the stream was mainly gravel and mud ( Andersen & Johanson, 1992). In the Democratic Republic of the Congo Lehmann (1979) found his specimens in a stream with strong current. From South Africa the species is known from the Santa River in Lydenburg District.

Remarks. The specimens from Tanzania and South Africa clearly conform to T. fuga , but there is some difference from Lehmann’s description in the tergite setation, probably due to intraspecific variation.

Figures

FIGURE 3. Thienemanniella fuga Lehmann. Adult male. A. Wing. B. Tentorium, stipes and cibarial pump. C. Antenna. D. Thorax. E. Hypopygium. Adult female. F. Wing. G. Genitalia, ventral view.