Xylochironomus yue, Liu & Tang, 2025

Liu, Shutang & Tang, Hongqu, 2025, Xylochironomus Cranston newly recorded in the Oriental region (Diptera, Chironomidae), with description of three new species, ZooKeys 1257, pp. 127-135 : 127-135

Xylochironomus yue sp. nov.

Figs 1 C , 1 G , 2 D

Material examined.

Holotype: M, China • Guangdong Province, Guangzhou City, Conghua District, Lyutian Town, Fentian , 23°50'N, 113°56'E, alt. 260 m, light traps, 02. iv. 2018, leg. HQ Tang . Paratype: • 1 M, as holotype .

Diagnosis.

The new species can be separated from congeners by the large wing length (c. 2.0 mm), wing squama with 1–3 setae, and the outer seta of the superior volsellae distinctly extending beyond the apex of the superior volsellae.

Etymology.

For the type locality, “ yue ” is an abbreviation of Guangdong Province. The name is a noun in apposition.

Description.

Male imago ( N = 4).

Total length 3.0– 3.2 mm. Wing length 1.8–1.9 mm. Total length / Wing length 1.68–1.75.

Head. Frontal tubercle present, ca. 5 μm long. Antenna terminal flagellomere 510 μm ( N = 1) long. AR 0.80 ( N = 1). Temporals with 10–12 inner verticals. Clypeus with 18–21 setae. Lengths of palpomeres 1–5 (in μm): 30–35; 40–45; 120–125; 125–130; 235–240.

Thorax ( N = 1). Acrostichals 14; dorsocentrals 8; prealars 3; scutellars 9, uniserial.

Wing. VR 1.18–1.20. R, R 1 and R 4 + 5 with more than 40 setae. Squama with 1–3 setae.

Legs. Scale of fore tibia 30 μm long; spurs of mid tibia and hind tibia 35–45 μm and 50–60 μm long, respectively. Lengths and proportions of legs as Table 3 .

Hypopygium (Figs 1 G , 2 D ). Tergite IX with 6–10 median setae, arranged in one row, and 4–6 margin setae on each side. Posterior margin of TIX somewhat smooth. Anal point parallel, 60 μm long, extending not beyond the inferior volsella. Gonocoxite 150–155 μm long, superior volsella 55–60 μm long, with three basal inner setae and one outer seta 80–85 μm long, extending to the apex of inferior volsella slightly. Gonostylus 120–130 μm long, with attenuated apex. HR 1.20–1.25.

Remarks.

This new species resembles Xylochironomus kakadu Cranston in the shape of the posterior margin of TIX and superior volsella, while the outer seta of the superior volsella is different, clearly extending beyond the terminal of the superior volsella in this new species, but relatively shorter in the latter, less than the whole length of the superior volsella.

Figures

Figure 1. Color photos of wing apex (A – C, arrows indicate the costa disjunction), abdominal terminal (D, arrow indicates the constricted anterior TVIII) and male genitalia (E – G). A, E. X. meng sp. nov.; B, D, F. X. mulu sp. nov.; C, G. X. yue sp. nov. Scale bars: 200 µm (A – C); 100 µm (D – G).

Figure 2. Color photos of Xylochironomus thorax (A) and line drawings of genitalia (B – D). A, B. X. meng sp. nov., arrow indicates the thick parapsidal suture; C. X. mulu sp. nov.; D. X. yue sp. nov. Scale bars: 100 µm (A); 50 µm (B – D).