Parachironomus nankaiensis Liu & Lin, 2023

Liu, Wen-Bin, Wang, Ying, Zhao, Kang-Zhu, Wang, Cheng-Yan, Zhang, Jun-Yu, Yan, Chun-Cai & Lin, Xiao-Long, 2023, New species, a new combination, and DNA barcodes of Parachironomus Lenz, 1921 (Diptera, Chironomidae), ZooKeys 1153, pp. 121-140 : 121

Parachironomus nankaiensis Liu & Lin sp. nov.

Figs 3 , 4 , 7

Material examined.

Holotype. Male (SHOU: XL599), China, Xizang Autonomous Region , Shannan City , Gongga County, Gangdui Town , 29.27888°N, 90.82323°E, 3586 m a.s.l., 18.VII.2014, sweep net, leg: X.L. Lin.

Diagnostic characters.

The species can be distinguished from known species of Parachironomus by the following combination of characters: frontal tubercles small; squama with seven setae; anal tergite bands V-shaped, separated; superior volsella narrower at base, curved and expanded in the distal part, with a bare lamellar projection as wide as apex of volsella; inferior volsella reaching slightly beyond anal tergite margin; gonostylus slender, slightly curved in the middle, tapered to the apex.

Description.

Adult male (n = 1). Total length 3.90 mm. Wing length 2.51 mm. Total length/wing length 1.56. Wing length/length of profemur 2.64.

Coloration. Thorax dark brown with dark spots. Legs brown. Abdomen yellowish green to brown, tergites I-V yellowish green, tergites VI-VIII yellowish brown, hypopygium brown.

Head (Fig. 3C ). Antenna with 11 flagellomeres, ultimate flagellomere 699 μm long. AR 1.60. Frontal tubercles small, 9 μm long, 8 μm wide. Temporal setae 14, including 4 inner verticals; 4 outer verticals; and 6 postorbitals. Clypeus with 11 setae. Tentorium 154 μm long, 39 μm wide. Palpomere lengths (in μm): 30; 42; 115; 146; 235; Pm5/ Pm3 2.04.

Thorax (Fig. 3F ). Antepronotals with 3 setae, acrostichals 6, dorsocentrals 10, prealars 3. Scutellum with 10 setae.

Wing (Fig. 7A ). VR 1.11. R with 16 setae, R1 with 14 setae, R4+5 with 22 setae. Brachiolum with two setae. Squama with seven setae.

Legs. Front tibia with three subapical setae, 80, 87 and 93 μm long. Combs of mid tibia 33 μm wide with 19 μm long spur, and 29 μm wide with 27 μm long spur; combs of hind tibia 30 μm wide with 20 μm long spur, 65 μm wide with 36 μm long spur. Tarsomere 1 of mid and hind legs without sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 5 .

Hypopygium (Figs 4C, F, I , 7B, C ). Tergite IX with 14 setae at base of anal point and shoulder-like posterior margin of anal tergite. Laterosternite IX with three setae. Anal point originating from caudal margin of anal tergite, almost parallel-sided, moderately expanded at apex, 50 μm long, 9 μm wide at base, 10 μm wide apically. Anal tergite bands V-shaped, separated (Fig. 4F ). Phallapodeme 80 μm long. Transverse sternapodeme 59 μm long. Superior volsella narrower at base, curved and expanded in the distal part, with a bare lamellar projection as wide as apex of volsella, 80 μm long, 22 μm wide at apex; and bearing six long setae at apex, free microtrichia. Inferior volsella with fairly blunt caudal projection, reaching slightly beyond anal tergite margin, and covered with microtrichia (Fig. 4I ). Gonocoxite 143 μm long, with four stout setae placed along inner margin. Gonostylus 169 μm long, slender, slightly curved in the middle, tapered to the apex, bearing seven setae along inner margin and one single seta at apex. HR 0.85. HV 2.31.

Etymology.

Name after Nankai University, the institution of study and work for Prof. Xin-Hua Wang; noun in nominative case.

Distribution.

China (Xizang).

Figures

Figure 3. Head (A-C) and thorax (D-F) of Parachironomus species A P. demissum (Yan, Wang & Bu), comb. nov. B P. wangi Liu & Lin, sp. nov. C P. nankaiensis Liu & Lin, sp. nov. D P. demissum (Yan, Wang & Bu), comb. nov. E P. wangi Liu & Lin, sp. nov. F P. nankaiensis Liu & Lin, sp. nov. Scale bars: 200 μm.

Figure 4. Hypopygium A P. demissum (Yan, Wang & Bu), comb. nov. B P. wangi Liu & Lin, sp. nov. C P. nankaiensis Liu & Lin, sp. nov. Anal point D P. demissum (Yan, Wang & Bu), comb. nov. E P. wangi Liu & Lin, sp. nov. F P. nankaiensis Liu & Lin, sp. nov. Superior volsella G P. demissum (Yan, Wang & Bu), comb. Nov. H P. wangi Liu & Lin, sp. nov. I P. nankaiensis Liu & Lin, sp. nov. Scale bars: 50 μm.

Figure 7. Parachironomus nankaiensis Liu & Lin, sp. nov. holotype male A wing B hypopygium, dorsal view C hypopygium, ventral view.