Sergentia (Baicalosergentia) kizakiensis

Sergentia (Baicalosergentia) kizakiensis (Tokunaga, 1940)

Pentapedilum kizakiensis Tokunaga, 1940: 290 (as subgenus Phaenopsectra).

Phaenopsectra kizakiensis: Sasa & Yamamoto, 1977: 313; Sasa, 1984: 54; Sasa & Hirabayashi, 1991: 110; Sasa & Suzuki, 2000: 179.

Sergentia kizakiensis: Yamamoto, 2010: 224; Yamamoto & Yamamoto, 2014: 339; Yamamoto, Suzuki & Yamamoto, 2019: 67 (as subgenus Baicalosergentia).

Stictochironomus kamiprimus Sasa & Hirabayashi, 1991: 110.

Material examined. 5 ♂♂ (NKU: K5B28, K5B28, K5B42, K5B44; NKU & BOLD Sample ID: K5B45), CHINA: Zhejiang Province, Taizhou City, Tiantai County, Huadingshan Mountain, 29.2523°N, 121.091°E, 1000m a.s.l., 12.IV.2011, Sweep net, leg. X.L. Lin.

Diagnostic characters. The male imago can be distinguished from known species of the genus by having wings covered with microtrichia; LR 1 > 1; mid tarsomere 1 with 10–14, 12 sensilla chaetica; superior volsella curbed only at tip, without lateral seta.

Description

Male (n = 5)

Total length 5.68–7.08, 6.24 mm. Wing length 3.40–4.20, 3.71 mm. Total length/wing length 1.60–1.78, 1.68. Wing length/length of profemur 2.62–2.89, 2.78.

Coloration. Head, legs and abdomen dark brown; wing brown; thorax dark brown.

Head. AR 2.49–3.38, 2.83. Ultimate flagellomere 0.98–1.19, 1.04 mm long. Temporal setae 16–21, 19 including 3–6, 4 inner verticals; 11–13, 11 outer verticals and 2–4, 3 postorbital. Clypeus with 23–38, 31 setae. Tentorium 185–215, 196 μm long, 62–80, 68 μm wide. Palpomere lengths (in μm): 70–79, 75; 70–92, 84; 189–220, 202; 198–251, 223; 253–317, 275. L: 5 th /3 rd 1.29–1.44, 1.36.

Wing (Fig. 1A). VR 1.02–1.03. Brachiolum with 2–3, 2 setae. R with 46–56, 52 setae, R 1 with 48–58, 53 setae, R 4+5 with 120–130, 126 setae, M 1+2 with 69–89, 80 setae, M 3+4 with 54–73, 64 setae, Cu 1 with 18–31, 24 setae, remaining veins bare. Cell r 4+5, m with and m 3+4 with numerous setae. Squama with 28–30, 28 setae.

1+2

Thorax (Fig. 1B). Dorsocentrals 17–28, 22; acrostichals 4–5, 5; prealars 6–8, 6. Scutellum with 24–30, 26 setae.

Legs. Scale on fore tibia rounded, 50–75, 60 μm long, sometimes with a small lateral spine. Mid tibia with one 28–32, 30 μm long spur; spurs of hind tibia 28–33, 30 μm and 13–16, 15 μm long. Width at apex of fore tibia 75–88, 81 M m, of mid tibia 63–90, 78 M m, of hind tibia 75–95, 83 M m. Mid tarsomere 1 with 10–14, 12 sensilla chaetica. Lengths (in μm) and proportions of legs as in Table 1.

Hypopygium (Fig. 1C). Tergite IX with 4–10, 8 median setae. Anal point with rounded apex. Laterosernite IX with 2–3, 2 setae. Superior volsella digitiform, with four inner setae, and without lateral setae. Phallapodeme 115–155, 134 μm long. Transverse sternapodeme 75–105, 85 μm long. Gonocoxite 233–273, 249 μm long. Gonostylus μm 172–216, 192 μm long. Inferior volsella straight, 145–175 μm long, with 24–30, 26 setae. HR 1.26–1.35, 1.30. HV 3.03–3.58, 3.25.

Distribution. China, Japan.

Remarks. Sergentia kizakiensis is redescribed here based on additional material from China. Based on morphological characters, Chinese specimens fit well with the original description (Tokunaga 1940), but a few differences are noted: Chinese specimens have a higher AR (2.49–3.38), and 3–7 inner setae on superior volsella, as compared to Japanese specimens (Sasa 1984, Sasa and Suzuki 2000), described with AR = 2.3–2.4 and superior volsella with 3–7 inner setae. Sergentia kizakiensis includes two DNA barcodes clustering into two BINs in BOLD: the BIN (BOLD: ADY6241) from China with a genetic divergence of 4.65% to the BIN (BOLD: ACH8232) from Japan.