Pseudorthocladius (Pseudorthocladius) digitus, Ren, Jing, Lin, Xiaolong & Wang, Xinhua, 2014

Ren, Jing, Lin, Xiaolong & Wang, Xinhua, 2014, Review of genus Pseudorthocladius Goetghebuer, 1943 (Diptera, Chironomidae) from China, ZooKeys 387, pp. 51-72 : 57-58

Pseudorthocladius (Pseudorthocladius) digitus sp. n. Figures 14-18

Diagnosis.

The male imago can be distinguished from the known species of the genus by the following combination of characters: anal point rounded and reaching beyond the caudal margin of Tergite IX; inferior volsella finger–shaped; squama bare; anal lobe reduced.

Description.

Adult male (n = 1). Total length 2.43 mm. Wing length 1.55 mm. Total length/wing length 1.57. Wing length/length of profemur 2.54.

Coloration. Head, abdomen, legs brown; thorax with yellow ground with brown postnotum and preepisternum.

Head. Antenna with 13 flagellomeres. Terminal flagellomere length 300 μm. AR 0.74. Temporal setae 7, including 4 inner verticals, 3 outer verticals. Clypeus with 2 setae. Tentorium 110 μm long, 24 μm wide. Palpomere lengths (in μm): 29, 31, 60, 108, -.

Wing (Figure 14). Anal lobe reduced. Brachiolum with 1 seta; R with 7 setae; R1 with 1 seta; other veins bare. Squama bare. Costa extention 41 μm long. Cu1 slightly curved.

Thorax (Figure 15). Antepronotum with 5 lateral setae, dorsocentrals 7, acrostichals 2, prealars 5. Scutellum with 9 setae.

Legs. Pulvilli present. Spur of fore tibia 50 μm long, spurs of mid tibia both 29 μm long; hind tibia with a long spur 60 μm long, a short spur 29 μm long and comb composed of 12 spines. Width at apex of fore tibia 43 μm, of mid tibia 36 μm, of hind tibia 45 μm. Lengths (in μm) and proportions of legs as in Table 5.

Hypopygium (Figures 16-18). Laterosternite IX with 3 setae. Anal point (Figure 18) rounded and reaching beyond caudal margin of Tergite IX, maximum width 22 μm, with 10 long marginal setae. Phallapodeme 48 μm long. Transverse sternapodeme 50 μm long with small oral projection. Virga absent. Gonocoxite 178 μm long with 6 strong setae along inner margin. Inferior volsella (Figure 18) finger–shaped, parallel–sided and rounded in the apex, bearing some weak setae along the margin and covered by microtrichia. Gonostylus 84 μm long, narrow at base, widen to the distal, with 3-4 setae along inner margin. Crista dorsalis visible, relatively low. Megaseta 10 μm long. HR 2.11. HV 2.89.

Female, pupa and larva unknown.

Type materials.

Holotype: ♂ (BDN No.05327), China: Fujian Province, Wuyi City, Wuyi Mountain, 27°45'N, 118°03'E, 26.iv.1993, Xinhua Wang, sweep net.

Etymology.

The specific name is from Latin, digitus, meaning “finger”, referring to the finger–shaped inferior volsella.

Remarks.

Pseudorthocladius (Pseudorthocladius) digitus sp. n. is close to Pseudorthocladius (Pseudorthocladius) yakuxeyeus (Sasa & Suzuki, 2000) in the antenna ratio (0.71-0.74) and finger–liked inferior volsella. But it can be separated from the latter by having rounded anal point reaching beyond the caudal margin of tergite IX, reduced wing anal lobe and bare squama.

Distribution.

The new species is known from Fujian Province in Oriental China.