Pseudorthocladius (Pseudorthocladius) cylindratus, 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 : 55-57

Pseudorthocladius (Pseudorthocladius) cylindratus sp. n. Figures 8-13

Diagnosis.

The male imago can be distinguished from the known species of the genus by the following combination of characters: cylindrical anal point; well–developed triangular inferior volsella; low AR (0.66) and high VR (1.37).

Description.

Adult male (n = 6). Total length 1.68-1.97, 1.87 mm. Wing length 1.04-1.19, 1.15 mm. Total length/wing length 1.53-1.75, 1.63. Wing length/length of profemur 2.64-2.88, 2.71.

Coloration. Head, abdomen, legs light brown; thorax with light brown ground with brownish black postnotum and preepisternum.

Head. Antenna with 13 flagellomeres. Terminal flagellomere length 235-264, 254 μm. AR 0.65-0.67, 0.66. Temporal setae 8-10, 9, including 3-6, 4 inner verticals, 4-5, 5 outer verticals, and 0-2, 1 postorbital. Clypeus with 8-11, 10 setae. Tentorium 96-113, 103 μm long, 18-21, 19 μm wide. Palpomere lengths (in μm): 22-26, 24; 24-28, 26; 60-72, 65; 84-91, 86; 113-137, 130. L: 5th/3rd 1.87-2.28, 2.00.

Wing (Figure 8). VR 1.33-1.43, 1.37. Anal lobe obtuse. Brachiolum with 1 seta; R with 5-13, 9 setae; R1 with 1-4, 2 setae; other veins bare. Squama with 1-3, 2 setae. Costal extension 80-84, 81 μm long. Cu1 slightly curved.

Thorax (Figure 9). Antepronotum with 4-6, 5 lateral setae, dorsocentrals 9-13, 11, acrostichals 3-7, 5, prealars 3-5, 4. Scutellum with 4-5, 5 setae.

Legs. Pulvilli present. Spur of fore tibia 29-41, 34 μm long, spurs of mid tibia 19-29, 22 μm and 19 μm long; hind tibia with a long spur 36-41, 38 μm long, a short spur 24-31, 27 μm long and comb composed of 10-12, 11 spines. Width at apex of fore tibia 34-46, 37 μm, of mid tibia 29-31, 30 μm, of hind tibia 31-36, 33 μm. Lengths (in μm) and proportions of legs as in Table 3.

Hypopygium (Figures 10-13). Laterosternite IX with 4-6, 5 setae. Anal point (Figure 12) cylindrical and 45-49, 48 μm long and with 10-13, 11 stout setae, 23-28, 25 μm long. Phallapodeme 31-36, 34 μm long. Transverse sternapodeme 65-67, 66 μm long and convex in the middle. Virga absent. Gonocoxite 117-137, 123 μm long, with 7 setae along inner margin. Inferior volsella (Figure 12) developed and triangular with 3-4, 3 strong marginal setae. Gonostylus (Figure 13) 65-72, 67 μm long, narrowed at base and distal end, widen in the middle. Megaseta 8-10, 9 μm long. HR 1.83-1.90, 1.85. HV 2.74-3.14, 2.78.

Female, pupa and larva unknown.

Type materials.

Holotype: ♂ (BDN No.26348), China: Hunan Province, Chenzhou City, Yizhang County, Mang Mountain, 25°24'N, 113°18'E, 22.vii.2004, Chuncai Yan, light trap. Paratypes (5 ♂♂): 4 ♂♂, as holotype; 1 ♂, Hainan Province, Changjiang County, Bawang Mountain, 19°15'36"N, 109°03'18"E, 10.v.1988, Xinhua Wang, sweep net.

Etymology.

The specific name is from Latin, cylindratus, meaning "in the form of a cylinder", referring to the cylindrical anal point, which is unique in the genus.

Remarks.

The new species resembles Pseudorthocladius (Pseudorthocladius) amplicaudus Sæther & Sublette, 1983 in the structure of hypopygium, but the new species can be separated from latter on the basis of main characters in Table 4.

Distribution.

The new species is known from Hunan, Hainan Province in Oriental China.