Hydrosmittia continalinea, Zhang, Ruilei, Liu, Wenbin, Ferrington, Leonard C. & Wang, Xinhua, 2016

Zhang, Ruilei, Liu, Wenbin, Ferrington, Leonard C. & Wang, Xinhua, 2016, Two new species of genus Hydrosmittia Ferrington & Saether (Diptera: Chironomidae) from China, Zootaxa 4121 (2), pp. 167-174 : 169-171

Hydrosmittia continalinea sp. n.

( Figure 1 )

Type material. Holotype, male (BDN No. 12386), China, Sichuan Province, Kangding County, Zheduo River, 2120m, 8. VI. 1996, light trap, X. Wang. Paratypes: 1 male, Sichuan Province, Ya’an City, Qingyi River, 2120m, 8. VI, 1996, light trap, X. Wang. 3 males, Sichuan Province, Yingjing County, Huatan Town, Mixi River, 940m, 17. VI, 1996, light trap, X. Wang. 10 males, Sichuan Province, Baoxing County, 1100m, 19. VI, 1996, light trap, X. Wang.

Etymology. From Latin continens, continuous, and linea, line, referring to costal extension continued with a long false vein.

Diagnostic characters. The male imago differs from other Hydrosmittia in lacking inner verticals, the wing with a false vein continuing from the apex of R4+5, low AR (0.18–0.20), antennal flagellomere with short and sparse plume and the virga consisting only of a small triangular median plate.

Male imago (n = 7)

Total length 1.98–2.43, 2.22 mm. Wing length 1.10–1.43, 1.28 mm. Total length/wing length 1.68–1.82, 1.75. Wing length/ length of profemur 3.19–3.47, 3.33.

Coloration. Head and thorax dark brown, abdominal segments yellowish brown. Antenna and leg brown.

Head. AR 0.18–0.20, 0.19. Terminal flagellomere 100–125, 113 µm long. Antennal flagellomere with short and sparse plume ( Fig. 1A ). Temporal setae 4–8, 5, consisting only of outer verticals. Clypeus with 2–8, 5 setae. Cibarial pump, tentorium and stipes as in Fig. 1B . Tentorium 110–135, 120 µm long, stipes 72–95, 84 µm long. Palpomere lengths (in µm): 25–30, 28; 25–38, 33; 63–80, 73; 75–110, 86; 95–123, 116. Length of 5th palpomere/ 3rd palpomere 1.50–1.70, 1.58. Third palpomere with 1–2 lanceolate sensilla clavata.

Thorax. Median antepronotal lobes well developed, antepronotum with 3–5, 4 lateral setae. Dorsocentrals 4–6, 5, acrostichals 2, prealars 3–5, 4. Scutellum with 3–6, 5 setae.

Wing ( Fig. 1C ). VR 1.23–1.33, 1.28. Anal lobe well developed. Costal extension 100–180, 125 µm, with long false vein. R4+5 ending almost opposite to apex of M3+4; Cu1 sinuate. Brachiolum with 1 seta, R with 1–3, 2 setae, other veins bare.

Legs. Spur of front tibia 20–27, 24 µm long, spurs of middle tibia 23–33, 26 µm and 12–20, 16 µm long, of hind tibia 22–32, 29 µm and 12–22, 16 µm long. Width at apex of front tibia 25–32, 28µm, of middle tibia 22–30, 26 µm, of hind tibia 25–35, 31 µm. Comb of hind leg with10–13, 12 setae. Lengths and proportions of legs as in Table 2.

Hypopygium ( Fig 1D–E ). Anal point 32–44, 36 µm long, apex free of microtrichia. Tergite IX with 12–18, 15 setae; laterosternite IX with 2–4, 3 setae. Phallapodeme 65–88, 80 µm long; transverse sternapodeme 67–82, 76 µm long, oral projections well developed. Virga ( Fig. 1D ) consisting of 9–14, 12 µm long small triangular median plate. Gonocoxite 160–200, 178 µm long; inferior volsella well developed, reaching to 0.54–0.59, 0.56 gonocoxite length; accessory lobe well developed and reaching 0.66–0.71, 0.69 gonocoxite length, free at apex. Gonostylus 62–92, 74 µm long, without distinct heel; megaseta 8–10, 9 µm long. HR 2.16–2.59, 2.41, HV 2.62–3.36, 3.02.

Distribution. Sichuan Province, China (Oriental China).

Remarks. The present new species belongs to the ruttteri group based on the following combination of characters: inner verticals absent, wing with developed anal lobe and false vein, oral projection of transverse sternapodeme well developed, and inferior volsella with accessory lobe. The species is very close to Hydrosmittia falsicostata Ferrington & Saether , but differs from the later by the antennal flagellomeres characteristically with short and sparse plume, low AR (0.18–0.20), smaller body, much shorter false vein and the virga consisting only of a small triangular median plate.

Fe ti ta1 ta2 ta3 ta4 P1 325–430, 384 410–530, 492 200–280, 246 95–160, 129 75–105, 94 45–65, 58 P2 475–610,554 485–610, 574 215–295, 262 100–150, 134 80–110,104 50–70,62 P3 445–580,514 475–600, 556 225–310, 278 120–170, 151 110–155, 141 55–75,68 ta5 LR BV SV BR

P1 40–65, 57 0.49–0.54, 0.50 3.39–3.68, 3.55 3.39–3.68, 3.55 1.29–2.00,1.72

P2 55–65,61 0.43–0.48,0.46 3.63–4.12, 3.86 4.07–4.54,4.31 1.63–3.17, 2.69

P3 55–65,62 0.47–0.53,0.50 3.02–3.37,3.18 3.61–4.09,3.86 2.86–3.29,3.00

Figures

FIGURE 1 A – E. Hydrosmittia continalinea sp. n. A. antenna. B. cibarial pump, tentorium and stipes. C. wing. D. virga. E. hypopygium, left dorsal aspect, right ventral aspect.