Limnophyes nudus, Song & Zheng & Wang & Qi, 2020

Song, Chao, Zheng, Jiacheng, Wang, Xinhua & Qi, Xin, 2020, A new species of Limnophyes Eaton (Diptera: Chironomidae) from Xizang, China, Zootaxa 4722 (3), pp. 295-300 : 296-299

Limnophyes nudus sp. nov.

Type material: Holotype: ♂ ( BDN No. CH477), China: Xizang Autonomous Region, Linzhi City , 94.36°E, 29.64°N, 8.VII. 2014, Song C, light trap . Paratype: 1♂ the same data as holotype .

Etymology. From Latin, nudus means bare, referring to the bare inferior volsella.

Diagnosis. The male adult can be separated from the previous recorded species of Limnophyes minimus group species by the combination of the following characters: antenna with 13 flagellomeres; AR of 0.85–1.00; a dorsal to posterior group of setae on the preepisternum in addition to the anterior row; bluntly triangular anal point; thumblike inferior volsella, 3 setae at base and upper part bare; gonostylus inner margin broadened, with three strong spines; phallapodeme with ring-like structure; virga consisting of two fused spines.

Description.

Adult males (n = 2). Total length (TL) 2.37–2.43 mm. Wing length (WL) 1.35–1.40 mm. TL/WL 1.65–1.80. Wing length /length of profemur 2.87–2.92.

Coloration. Head, thorax, abdomen, and hypopygium dark brown. Legs light brown.

Head. Antenna with 13 flagellomeres, AR 0.85–1.00. Ultimate flagellomere 280–310 μm long; temporal se- tae 2–5, including 0–2 inner verticals, 2 outer verticals and 0–1 postorbital. Clypeus with 4–10 setae. Tentorium 125–137 μm long, 20–23 μm wide. Palp segments lengths (n = 1, in µm): 25; 48; 80; 75; 120. Length of palp seg- ments 5 th /3 rd 1.50.

Wing ( Figure 2A ). VR 1.23–1.31. Brachiolum with 1 seta, R with 4–6 setae. Squama with 5 setae.

Thorax ( Figure 2B ). Antepronotals consisting of 0–2 median setae. Humeral pit present, humerals with 6 lanceolate setae. Acrostichals absent, prealars 8 (1); Dorsocentrals 32–38 lanceolate setae, consisting of 11–15 lanceolate close to antepronotum, 10–13 non-lanceolate around mid-scutum, 11–13 lanceolate prescutellars; prealars 7; preepisternum with 6 (1) setae in interior row and 3 (1) setae to dorsal to posterior group. Scutellum with 2 setae.

Legs. Spur of fore tibia 35–45 µm long, spurs of mid tibia 10–13 µm and 13–23 µm long; spurs of hind tibia 40–45 µm and 13–15 µm long. Comb of hind leg with 13 sparse spines, longest 28–35 µm, and shortest 15–18 µm. Lengths and proportions of legs as in Table 1 .

Hypopygium ( Figure 2 C–F). Laterosternite IX with 2–3 setae. Anal point relatively small, broad-based, bluntly triangular and with about 6–12 marginal setae. Transverse sternapodeme 37–47 µm long, with well-developed oral projections. Phallapodeme 65–75 µm long, with ring-like structure in the middle. Virga 30–33µm long, consisting of two fused spines. Gonocoxite 132–138 µm long. Inferior volsella thumb-like, 25– 25 µm long, 3 setae at base and apical part bare. Gonostylus ( Fig 2D ) relatively short, 80–88 µm long with 3 strong spines, bubble-like inner margin; crista dorsalis pointed; megaseta 20–22 µm long. HR 1.50–1.72; HV 2.78–2.96.

Adult female and immatures unknown.

Remarks. The new species clearly belongs to the minimus group because the preepisternum with anterior row of setae, lanceolate humerals and prescutellars, virga consisting of 2 fused spine, pointed crista dorsalis. The species will be located to -10. Lanceolate prescutellars numerous (13–17) (p. 22) in the key of Saether (1990a). The male of L. nudus sp. nov. closely resembles L. cranstoni Saether , L. simensis Ree and L. pentaplastus (Kieffer) in hypopygium, but can be separated by the following morphological characters as in Table 2 .

Figures

FIGURE 2. Limnophyes nudus sp. nov. Male: (A) Wing; (B) Thorax; (C) Hypopygium, dorsal view; (D) Gonostylus (paratype); (E) Hypopygium, dorsal aspect to the left and ventral aspect to the right; (F) Inferior volsella, ventral view.