Orthocladius (Euorthocladius) angustus, Kong & A.Saether & Wang, 2012

Kong, Fanqing, A. Saether, Ole & Wang, Xinhua, 2012, A review of the subgenera Euorthocladius and Orthocladius s. str. from China (Diptera: Chironomidae), Zootaxa 3537, pp. 76-88 : 77-78

Orthocladius (Euorthocladius) angustus sp. n.

( Figs 1–3)

Type material. Holotype male (BDN No. 12401), CHINA: Sichuan Province, Ganzi City, Yajiang River , 14.vi.1996, sweep net, X. Wang.

Diagnostic characters. The species can be separated from other members of the subgenus by having low AR (0.47), short anal point, and inferior volsella with dorsal part long and narrow.

Etymology. From Latin, angustus , narrow, referring to the shape of the dorsal part of inferior volsella.

Description. Male (n = 1).

Total length 3.27 mm. Wing length 2.00 mm. Total length / wing length 1.64. Wing length / length of profemur 2.67.

Coloration. Head and thorax brown. Antenna, legs and abdomen yellowish brown.

Head. AR 0.47. Ultimate flagellomere 320 µm long. Temporal setae 9, including 1 inner vertical, 3 outer verticals and 5 postorbitals. Clypeus with 13 setae. Cibarial pump, tentorium and stipes as in Fig. 1. Tentorium 154 µm long, 44 µm wide. Stipes 132 µm long, 52 µm wide. Palpomere lengths (in µm): 35, 44, 90, 91, 152. Length ratio of palpomeres 5/3 1.69.

Wing ( Fig. 2). Anal lobe well developed. VR 1.18. Costal extension 35 µm long. R with 8 setae, other veins bare. Squama with 21 setae.

Thorax. Antepronotum with 4 setae. Dorsocentrals 10, acrostichals absent, prealars 4. Scutellars 48, multiserial.

Legs. Spur of fore tibia 44 µm long, spurs of mid tibia 26 mm and 22 µm long, of hind tibia 52 µm and 26 mm long. Comb of 10 setae, shortest seta 25 µm, longest seta 50 µm. Width at apex of fore tibia 40 mm, of mid tibia 40 µm, of hind tibia 48 µm. Pseudospurs present on ta 1 and ta 2 of mid and hind leg, 15–18 m long. Sensilla chaetica absent. Lengths (in µm) and proportions of legs in Table 1.

Hypopygium ( Fig. 3). Tergite IX including anal point with 9 setae. Laterosternite IX with 11 setae. Anal point 35 µm long, 18 µm wide. Phallapodeme 70 mm long; transverse sternapodeme 150 µm long, oral projections well developed. Gonocoxite 187 µm long, superior volsella collar-like, inferior volsella with dorsal part long and narrow, and ventral part strongly extended below. Virga 25 µm long. Gonostylus 98 µm long, crista dorsalis long; megaseta 10 µm long. HR 1.91, HV 3.34.