Paratanytarsus tenuis Meigen 1830

Paratanytarsus tenuis (Meigen 1830) (Fig. 5)

Chironomus tenuis Meigen 1830: 255

Chironomus affinis Walker 1856: 162

Chironomus perlevis Walker 1856: 162

Paratanytarsus unicolor Kieffer 1922: 95

Tanytarsus similis Goetghebuer 1928: 139

Paratanytarsus tenuis (Meigen) Brundin 1947: 77 (Figs. 115, 115a); Reiss 1968: 218; 1971: 208; Reiss & Säwedal 1981: 102 (Fig. 15); Wang 2000: 641.

Material examined: 4 males (BDN 0 5090, 0 5093, 0 7655, 07656) Qinghai Province, Menyuan County, Fenglikou (37º22'N, 101º38'E). 18. vii. 1989.

Diagnostic characters: Anal tergite with well developed lateral teeth. Anal tergite bands V­shaped and narrowly separated in middle. Anal tergite with 2 pairs of long median tergite setae. Superior volsella roughly triangular. Digitus tapering to rounded apex and extending posterior to superior volsella. Median volsella distally with spatulate lamellae. Inferior volsella with distal part developed as club­shaped swelling and divided into 2 rounded lobes.

Male imago (n = 4)

Total length 3.44–356, 3.50 mm; wing length 2.24–2.44, 2.38 mm. Total length/wing length 1.42–1.54, 1.47; wing length/length of profemur 2.42–2.57, 2.51. Ground coloration yellowish brown and thorax with brown vittae; antenna and legs brown; abdomen yellowish brown.

Head: Frontal tubercles cylindrical, about 10–16 µm long. AR (n = 3) 1.23–1.85, 1.42; ultimate flagellomere 688–740, 703 µm long. Temporal setae (n = 3) including 3–5, 4 inner verticals, 2–4, 3 outer verticals and 2–4, 3 postorbitals. Clypeus with 10–14, 12 setae. Tentorium (n = 3) 120–136, 126 µm long, width 39–44, 42 µm. Palpomere lengths (in µm): 30–40, 35; 52–60, 57; 132–148, 139; 128–142, 134; 168–218, 199.

Wing: VR 1.06–1.18, 1.13 and Cu length 1020–1160, 1085 µm.

Thorax: (n = 3) Acrostichals 10–12, 11; dorsocentrals 9–11, 10; scutellars 0–4, 1; prealars 0–1, 1.

Legs: Front tibial spur 18 µm long. Spurs of middle tibia 25–30, 28 and 24–30, 27 µm, of hind tibia only 1 comb with spur 26–33, 30µm long. Combs of middle tibia composed of 16–21, 19 and14–18, 16 teeth, of hind tibia 24–28, 26 and 14–18, 17 teeth. Lengths (in µm) and proportion of legs are given in Table 5.

Hypopygium (Fig. 5): Anal tergite with well developed lateral teeth. Anal tergite bands V­shaped and narrowly separated in middle. Anal tergite with 2 pairs of long median tergite setae. Anal point broad, about 26–36, 32 µm long, with a pair of anal crests and 4– 8, 6 basal setae. Phallapodeme 60–90, 69 µm long. Transverse sternapodeme 26–38, 33 µm long, with oral projections. Gonocoxite 148–165, 159 µm long. Superior volsella roughly triangular, with 4–7, 6 dorsal and 4–6, 5 inner surface setae, and 1 seta at base arising on ventral side. Digitus tapering to rounded apex and extending posterior to superior volsella. Median volsella 68–90, 79 µm long, its lateral margin without lamellae, inner margin with about 4–7, 5 setiform lamellae, apically with bundles of spatulate lamellae. Inferior volsella 130–140, 136 µm long, apical divided into 2 lobes and with about 18–24, 22 setae. Gonostylus 160–180, 171 µm long. HR 0.87–1.03, 0.93; HV 1.98–2.20, 2.05.

Remarks: The shape of the superior and median volsella has some variation. The outer margin is shorter than the inner margin of the superior volsella in a specimen from China, whereas it is subequal in specimens described by Reiss & Säwedal (1981) from Mongolia and Greenland. The length and curvature of the median volsella from Chinese material are shorter and less than that described by Reiss & Säwedal (1981).

Distribution: The species is widely distributed in the Palaearctic and Nearctic Regions.