Stenochironomus zhengi Lin & Liu, 2021

Lin, Xiao-Long, Yao, Yuan, Yan, Chun-Cai & Liu, Wen-Bin, 2021, Stenochironomus zhengi sp. nov. from Dawei Mountain National Park, Yunnan China (Diptera: Chironomidae), Zootaxa 4970 (2), pp. 385-390 : 386-388

Stenochironomus zhengi Lin & Liu sp. nov.

( Figs 1–7 )

Type material. Holotype male (NKU: DWS114), CHINA: Yunnan Province, Honghe Hani and Yi Autonomous Prefecture , Pingbian Miao Autonomous County, Dawei Mountain National Park , 22.9131778°N, 103.6955528°E, 2056 m a.s.l., Malaise trap, 4–14.vi.2020, leg. L.-Z. Meng.

Diagnostic characters. The male imago can be separated from known species in this genus by the following combination of characteristics: mid and hind tibiae of legs with obviously dark brown combs; R with 28 setae, R 1 with 21 setae, R 4+5 with 30 setae; costal not extension beyond R 4+5; superior volsella much beyond posterior margin of tergite IX front portion parallel-sides, apically rounded.

Etymology. Name after Prof. Le-Yi Zheng, for his outstanding contributions to the knowledge of insect taxonomy in China, noun in genitive case.

Description. Male (n = 1).

Total length 5.00 mm. Wing length 3.08 mm. Total length / wing length 1.62. Wing length / length of profemur 2.11.

Coloration ( Fig. 1 ). Head, thorax and abdomen yellow. Antenna and hypopygium dark brown. Legs mostly yellow, mid and hind tibiae with obviously dark brown combs. Wing nearly transparent.

Head. Antenna with 13 flagellomeres. AR 1.18, ultimate flagellomere 720 µm long. Temporal setae 16, including five inner verticals, five outer verticals and six postorbitals. Clypeus with 28 setae. Tentorium 200 µm long, 78 µm wide. Stipes 130 µm long, 15 µm wide. The first segement of palpomere 110 µm long, other segments broken.

Wing ( Fig. 2 ). Anal lobe reduced. VR 1.13. Brachiolum with two setae. R with 28 setae, R 1 with 21 setae, R 4+5 with 30 setae. Costal not extension beyond R 4+5. Squama with eight setae.

Thorax ( Fig. 3 ). Dorsocentrals 28, acrostichals 22, prealars five, scutellum with 14 setae.

Legs. Fore leg: width at apex of tibia 75 µm long. Mid leg: width of apex tibia 83 µm, tibia with two spurs 50 µm and 30 µm long. hind leg: width of apex tibia 88 µm, tibia with two spurs 38 µm and 38 µm long. Mid and hind tibiae with obviously dark brown fused combs, each comb 28–35 µm long. Lengths and proportions of legs in Table 1 .

Hypopygium ( Figs 4–7 ). Anal point 113 μm long, 25 µm wide at base, 18 µm wide at apex, apex of anal point swollen and rounded. Tergite IX with 23 long setae medially, posterior margin of tergite IX with 10 setae and eight spines. Phallapodeme 113 μm long; transverse sternapodeme 50 μm long. Gonocoxite 200 μm long. Superior vol- sella as in Figure 4 , much beyond posterior margin of tergite IX, 163 μm long, 33 μm wide at base, front portion parallel-sides, apically rounded, with 12 setae. Inferior volsella elongate, 260 μm long, with four long setae and a slender terminal spine. Gonostylus 290 μm long, HR 0.69, HV 1.72.

Remarks. The new species can be separated from other members of the genus by having an elongate and much beyond posterior margin of tergite IX superior volsella. The characters of the new species closely resemble Stenochironomus linanensis Qi, Lin, Liu & Wang, 2015 ( Qi et al. 2015). However, the new species differs from the latter on the basis of following characters: (1) the body length of the new species (5.00 mm) much longer than S. linanensis (2.9–3.8 mm); (2) setae in thorax of the new species (dorsocentrals 28, acrostichals 22, scutellum with 14 setae) much more than the latter species (dorsocentrals 9–13, acrostichals 9–14, scutellum with 5–6 setae); (3) the anal lobe of the new species reduced, whereas S. linanensis with a developed wing anal lobe.

Figures

FIGURE 1. Stenochironomus zhengi Lin & Liu sp. nov., male in alcohol.

FIGURES 2–4. Stenochironomus zhengi Lin & Liu sp. nov., male. 2. wing; 3. thorax; 4. superior volsella. Scar bar = 100 µm.

FIGURES 5–6. Stenochironomus zhengi Lin & Liu sp. nov., male. 5. hypopygium dorsal view; 6. hypopygium ventral view; Scar bar = 100 µm.

FIGURE 7. Stenochironomus zhengi Lin & Liu sp. nov., male. drawing of hypopygium. Scar bar = 100 µm.