Polypedilum (Tripodura) biloborum, Chen & Zhang, 2021

Chen, Jinxian & Zhang, Ruilei, 2021, Two new species of subgenus Tripodura Towns (Diptera, Chironomidae, Polypedilum) from Oriental China, Zootaxa 5072 (2), pp. 191-199 : 194-196

Polypedilum (Tripodura) biloborum sp. n.

( Figure 2 , GenBank accession Number MZ364753 , BIN number AEK0846) urn:lsid:zoobank.org:act:A2A05049-27DC-4798-BA0F-9D3B18DE59B7

Material examined: Holotype: Male ( JNU0609–02 ), China, Hainan Province, Baisha County, Nankai Township , Nandu River , 28.V.2020, light trap, H. Tang . Paratypes: 2 males as the holotype.

Etymology: From Latin, bi, two, and lobus, lobe, are referring to middle part of anal point with 2 pairs triangle transport lobes.

Diagnostic characters: Basal part of anal point with developed and pointed shoulders, middle part with 2 furrows, and distal part with a round transport lobe, wing with many spots.

Male imago (n =3)

Total length 2.76–2.82, 2.78 mm. Wing length 1.41–1.56, 1.51 mm. Total length/ wing length 1.77–1.96, 1.85. Wing length /length of profemur 1.87–2.12, 2.01.

Coloration. Head brown with yellow palpomeres. Thorax ( Figure 2A ) dark brown except yellow scutellum. Abdominal segments brown. Fore leg ( Figure 2B ): femur brown except apical 1/3 yellow, tibia, 1 st and 2 nd tarsi yellow, remaining segments brown. Middle and hind legs ( Figure 2B ): femur brown except apical 1/3 yellow, tibia yellow, 1 st, 2 nd and 3 rd tarsi brown except apical 1/6 yellow, remaining segments brown.

Wing ( Figure 2C ) stramineous with brown spots, one spot on basal cell r 4+5 and one spot on distal cell r 4+5, one spot on basal cell m 1+2 and stretching to apical margin, one spot on basal cell m 3+4 and one on apical cell m 3+4, one spot on middle cell an and stretching to apical cell an, one spot on cell cu.

Head. Antenna missing. Temporal setae 8–9, 9 including four inner verticals, 3–4, 4 outer verticals and 1–3, 2 postorbital. Clypeus with 13–15, 14 setae. Tentorium 125–126, 126 µm long, 14–15, 15 µm wide. Palpomere lengths (in µm): 28–40, 35; 25–45, 35; 61–98, 80; 96–109, 101; 173–195, 181.

Wing ( Figure 2C ). VR 1.06–1.23, 1.16. R with 11–16, 14 setae, R 1 with 10–17, 14 setae, R 4+5 with 12–16, 14 setae. Squama with 6–8, 7 setae.

Thorax ( Figure 2A ). Dorsocentrals 9–12, 10; acrostichals 10–16, 12; prealars 4–5, 5. Scutellum with 11–12, 12 setae.

Legs ( Figure 2B ). Terminal scale ( Figure 2D ) of fore tibia 33–42, 38 µm long, triangular and apically pointed. Spur of mid tibia 43–52, 47 um long including 19–22, 20 µm long comb, un-spurred comb 15–19, 17 µm long; spur of hind tibia 45–48, 46 µm long including 18–26, 22 µm long comb, un-spurred comb 15–21, 17 µm long. Width at apex of front tibia 34–43, 40 µm, of mid tibia 30–50, 42 µm, of hind tibia 33–52, 44 µm. Lengths (in µm) and proportions of legs ( Table 2).

Hypopygium ( Figure 2F ). Anal tergite bands weak. Anal tergite with 7–7, 7 median setae, laterosternite IX with 2–3, 3 setae. Posterior margin of tergite IX with developed lateral projections. Anal point 61–92, 78 µm long, basal with developed and pointed shoulders, middle part with 2 triangle lobes, and distal part with a round transport lobe. Phallapodeme 65–92, 83 µm long, transverse sternapodeme 25–34, 30 µm long. Gonocoxite 118–141, 127 µm long. Superior volsella ( Figure 2E ) slender and apically bended inwards, 60–89, 75 µm long, 11–17, 14 µm wide, with 3 strong inner setae on inner posterior margin directed inwards and one outer lateral seta. Inferior volsella almost parallel-sided, 94–95, 95 µm long with 8 oral setae and 1 apical seta. Gonostylus 158–171, 166 µm long, with 5–6, 6 long setae along inner margin. HR 0.72–0.82, 0.76, HV 1.62–1.75, 1.67.

Distribution: The species is only known from the type locality, Yunnan Province (Oriental China).

Remarks: The new species probably belongs to the griseoguttatum group, but without centre patch in cell bm area. In Asia, it resembles Japanese species P. (T.) sagittiferum in wing markings pattern and sculptural pattern of anal point ( Tokunaga, 1938). The new species distinguishes the latter by superior volsella and inferior volsella with fewer setae, strongly developed lateral projections to each side of the anal point. Also the new species is very close to P. (T.) jianfengense Song & Wang from China but easily differs from it by having more spots in wing.

Figures

FIGURES 2A-F. P. (Tri.) biloborum sp. n., male. A, thorax. B, legs. C, wing. D, spur of front tibia. E, superior volsella. F, hypopygium.