Heterotrissocladius flectus, Kong, Fanqing & Wang, Xinhua, 2011

Kong, Fanqing & Wang, Xinhua, 2011, Heterotrissocladius Spärck from China (Diptera: Chironomidae), Zootaxa 2733, pp. 63-68 : 63-65

Heterotrissocladius flectus sp. n.

( Figs. 1 A–B)

Type material. Holotype male (BDN No.14187), CHINA: Zhejiang Province, Tianmushan Natural Conversation area, 4.viii.1987, sweep net, H. Zou. Paratype: 1 male (BDN No.21221), CHINA: Guizhou Province, Daozhen County, Dashahe Natural Conversation area, 25.v. 2004, light trap, H. Tang.

Diagnostic characters. The new species can be separated from other members of the genus by having a distinctly curved inferior volsella and bare veins except vein R.

Etymology. From Latin, flect – means bent, referring to the shape of the inferior volsella.

Description. Male imago (n = 2).

Total length 2.38–3.83 mm. Wing length 1.43–1.75 mm. Total length / wing length 1.67–2.19. Wing length / length of profemur 2.30–2.69.

Coloration. Head light brown. Antenna, legs and abdomen yellowish brown. Thorax dark brown.

Head. AR 0.78–0.90. Temporal setae 10–11, including 4–5 inner verticals, 2–3 outer verticals and 3–4 postorbitals. Clypeus with 17 setae. Tentorium 119–135 Μm long, 33–35 wide. Palpomere lengths (in Μm): 13; 31–40; 80–92; 80–101; 154–170. Length ratio of palpomeres 5th/3 rd 1.67–2.13.

Wing ( Fig. 1 A). Anal lobe well developed. VR 1.22–1.26. R with 11–14 setae, other veins bare. Wing membrane with sparse setae, m1+2 with 3, r4+5 with c. 6 and cell an with 1–2 setae. Squama with 9–15 setae.

Thorax. Dorsocentrals 15–18; acrostichals 12–14; prealars 4–5; scutellars 7–9.

Legs. Spur of front tibia 31 m; of mid tibia 17–22 Μm and 9 Μm long; of hind tibia 26–57 Μm and 13–18 Μm long. Tibial comb 25–40 Μm long. Width at apex of front tibia 26–31 Μm, of mid tibia 22–26 Μm, of hind tibia 22– 31 Μm. Lengths (in Μm) and proportions of legs in Table 1.

Hypopygium ( Fig. 1 B). Anal point roughly triangular with pointed apex, 55–80 Μm long. Tergite IX with 17– 32 setae on the anal point. Laterosternite IX with 5–7 setae. Phallapodeme 40 Μm long; transverse sternapodeme 38–50 Μm long. Gonocoxite 170–210 Μm long. Inferior volsella distinctly curved apically, 25–45 Μm long, with 8– 10 setae. Gonostylus 78–80 Μm long, with triangular crista dorsalis. Megaseta 10–12 Μm long. HR 1.93–2.44; HV 3.60–4.83.

Remarks. According to Saether (1975), H. flectus can be included into the marcidus species group. The new species is close to H. hirtapex Saether (1975) in the structure of its hypopygium, particularly in the shape of gonostylus, but H. hirtapex has a shorter anal point and a lower number of setae on the wing.

Distribution. The present new species were collected in subtropical mountain area in Oriental China (Zhejiang and Guizhou Provinces).

Heterotrissocladius marcidus (Walker)

Metriocnemus marcidus Walker, 1856: 177 .

Metriocnemus aestivalis Goetghebuer, 1921: 76 .

Metriocnemus alticola Goetghebuer, 1934: 339 .

Metriocnemus cubitalis Kieffer, 1911: 200 .

Metriocnemus longicollis Kieffer, 1913: 34 .

Metriocnemus triangulifer Kieffer, 1924: 90 .

Heterotrissocladius marcidus (Walker) : Saether 1969: 45; Saether 1975: 27 –35; Wang 2000: 636.

Material examined. Sichuan Province, Litang County, Zhaisang District, sweep net, 13 males, 11.vi.1996, X. Wang; Jilin Province, Changbaishan Natural Conversation Area, sweep net, 2 males, 30.iv.1994, X. Wang; Xizang Autonomous Region, Mt. Shergmla, Malaise trap, 1 male, 28.ix.1997, T. Solhøy & J. Skartveit.

Remarks. Heterotrissocladius marcidus was first recorded by Walker in 1856 as the genus Metriocnemus . Goetghebuer (1921, 1934) and Saether (1975) have described this species in detail.

Distribution. The species has been recorded in Palaearctic, Nearctic and Oriental Region ( Saether, 1975; Yamamoto, 2004). It occurs in both Oriental (Sichuan and Tibet) and Palaearctic (Jilin) China.

Figures

FIGURE 1. Heterotrissocladius flectus sp. n.: A. Wing; B. Hypopygium.