Heterotrissocladius reductus, Kong, Fanqing & Wang, Xinhua, 2011

Kong, Fanqing & Wang, Xinhua, 2011, Heterotrissocladius Spärck from China (Diptera: Chironomidae), Zootaxa 2733, pp. 63-68 : 66-67

Heterotrissocladius reductus sp. n.

( Figs. 3 A–B)

Type material. Holotype male (BDN No. 02187), CHINA: Fujian Province, Wuyishan Mountain Natural Conversation area, 29.iv.1993, light trap, X. Wang.

Diagnostic characters. The new species can be separated from other members of the genus by having a triangular blunt anal point, a low and pointed crista dorsalis and a reduced anal lobe of wing.

Etymology. From Latin, reduc – means reduced, referring to the wing with reduced anal lobe.

Description. Male imago (n = 1).

Total length 2.45 mm. Wing length 1.48 mm. Total length / wing length 1.66. Wing length / length of profemur 2.54.

Coloration. Head, thorax and legs brown. Abdomen yellowish brown. Wing nearly transparent.

Head. AR 0.95. Temporal setae 10 including 3 inner verticals, 4 outer verticals and 3 postorbitals. Clypeus with 14 setae. Tentorium 125 Μm long, 27 Μm wide. Stipes 60 m long; 45 Μm wide. Palpomere lengths (in Μm): 15; 33; 88; 80; 125. Length ratio of palpomeres 5th/3 rd 1.42.

Wing ( Fig. 3 A). Anal lobe reduced. VR 1.14. R with 21 setae, R1 with 15, R4+5 with 21 and M1+2 with 65 setae; r4+5 with c. 150 setae, m1+2 with 95, m3+4 with c. 40 and cell an with 12 setae. Squama with 6 setae.

Thorax. Dorsocentrals 6; acrostichals 7; prealars 4; scutellars 14.

Legs. Spur of front tibia 31 Μm long; of mid tibia 20 Μm and 18 Μm long; of hind tibia 48 Μm and 20 Μm long including 31 Μm long comb. Width at apex of front tibia 38 Μm, of mid tibia 38 Μm, of hind tibia 40 Μm. All the tarsomeres lost.

Hypopygium ( Fig. 3 B). Anal point nearly triangular with blunt apex, 63 Μm long, 37 Μm wide. Tergite IX with 13 setae on the anal point; laterosternite IX with 4 setae. Phallapodeme 40 Μm long; transverse sternapodeme 97 Μm long. Virga 42 m long. Gonocoxite 163 Μm long. Inferior volsella 55 Μm long, with 12 long setae. Gonostylus widest in apical part and narrowed at base, 75 Μm long, with pointed crista dorsalis, megaseta 10 Μm long. HR 2.17, HV 3.27.

Remarks. According to Saether (1975), the new species can be included in the marcidus species group. It is close to H. cooki Saether (1975) in the most structures of its hypopygium, but can be separated by the much higher 5th/3 rd palpomere ratio (c. 1.0 in H. cooki ) and the much lower antennal ratio (AR 1.56–1.84 in H. cooki ).

Distribution. The new species was collected in a subtropical mountain area in Fujian province (Oriental China).

Figures

FIGURE 3. Heterotrissocladius reductus sp. n.: A. Wing; B. Hypopygium.