Parachironomus monochromus (van der Wulp)

Yan, Chun-Cai, Yan, Jiao, Jiang, Li, Guo, Qin, Liu, Ting, Ge, Xin-yu, Wang, Xin-Hua & Pan, Bao-ping, 2015, Parachironomus Lenz from China and Japan (Diptera, Chironomidae), ZooKeys 494, pp. 31-50 : 36

Taxon classification Animalia Diptera Chironomidae

Parachironomus monochromus (van der Wulp) Figs 8-10

Chironomus unicolor van der Wulp, 1859: 5 (primary homonym of Chironomus unicolor Walker, 1848).

Chironomus monochromus van der Wulp, 1875: 129 (replacement name for Chironomus unicolor van der Wulp).

Chironomus (Cryptochironomus) claviforceps Edwards, 1929: 389.

Tendipes (Parachironomus) monochromus (van der Wulp). - Kruseman (1933: 192).

Tendipes ( Cryptochironomus gr. Parachironomus ) monochromus (van der Wulp). - Goetghebuer (1937 in 1937-1954: 46).

Parachironomus monochromus (van der Wulp). - Brundin (1947: 55); Lehmann (1970: 146); Pinder (1978: 130); Albu (1980: 131); Langton (1991: 274); Kobayashi and Suzuki (1999: 82); Spies (2000: 126).

Material examined.

CHINA: 8 males, Tianjin City, Campus of Nankai University, 8 males, 12, 16. iv. 1985; 20. iv. 1986, X. Wang; 1 male, Hebei Province, Weichang County, Jixielinchang, 15. vii. 2001, sweep net, Y. Guo.

Diagnostic characters.

The species is distinguished by the following combination of characters: anal tergite with distinct cluster of enlarged posterodorsal setae; anal point basal section intergrading with anal tergite, distal part strongly angled to ventral; superior volsella without apical or posterolateral projection; inferior volsella with lobe at least to median; gonostylus mostly slender, slightly curved, with distal widening to dorsal peaking around 2/3 of gonostylus length (excerpt from Spies 2000: 129).

Redescription

(Chinese specimens). Male imago (n=9, unless otherwise stated). Total length 2.58-3.83, 3.38 mm. Wing length 1.30-1.98, 1.80 (8) mm. Total length/wing length 1.80-1.98, 1.88 (8). Wing length/length of profemur 2.28-2.57, 2.48 (8).

Coloration. Thorax yellowish green to dark brown. Front legs with femora yellowish green to dark brown, tibiae and tarsi dark brown except for tarsi I yellowish green in basal 4/5; mid and hind legs yellowish green to yellowish brown except for tarsi V dark brown. Abdomen yellowish green to dark brown.

Head. AR 1.86-2.27, 2.12. Terminal flagellomere 540-720, 673 µm long. Frontal tubercles absent (7) or present (2), cone-shaped, 15-22 µm high, 12-22 µm wide at base. Temporal setae 18-22, 20, including 5-7, 6 inner verticals, 7-8, 8 outer verticals, and 5-8, 6 postorbitals. Clypeus with 14-20, 17 (8) setae. Tentorium 100-133, 120 µm long, 18-43, 33 µm wide. Palpomere lengths (in µm): 30-50, 40; 35-58, 51; 103-133, 110; 130-180, 153 (8); 178-220, 201 (8). Length ratio 5th/3rd palpomere 1.21-1.73, 1.58 (8).

Thorax. Antepronotals 2-5, 3 (8), acrostichals 10-14, 12 (8), dorsocentrals 8-14, 11, prealars 4-6, 5 (8). Scutellum with 6-10, 8 (7) setae.

Wing (Fig. 8). VR 1.11-1.17, 1.15 (8), R with 16-27, 20 (8) setae, R1 with 10-17, 13 (8) setae, R4+5 with 21-29, 26 (8) setae. Brachiolum with 2-3, 2 (8) setae. Squama with 7-16, 12 (8) setae.

Legs. Front tibia with 3 subapical setae, 90-130, 104 (7), 98-133, 118 (6) and 120-138, 126 (3) µm long; spurs of mid tibia 24-33, 28 µm and 28-35, 31 µm long, comb with 30-42, 35 teeth, 10-12, 11 µm long; spurs of hind tibia 26-33, 31 µm and 28-35, 33 µm long, comb with 45-52, 48 teeth, 10-13, 12 µm long. Tarsus 1 of mid leg with 4-7, 6 (8) sensilla chaetica, hind leg without sensilla chaetica. Lengths (in µm) and proportions of legs as in Table 2.

Hypopygium (Figs 9, 10). Laterosternite IX with 2-3, 2 (8) setae. Anal tergite bands short, fading far apart medially. Tergite IX with 16-30, 21 (8) setae at base of anal point. Anal point 35-55, 48 (7) µm long, its base intergrading with conical tip of anal tergite; distal bare part narrow. Transverse sternapodeme 37-60, 52 (8) µm long. Phallapodeme 60-83, 73 (8) µm long. Superior volsella slightly curved, 70-95, 84 µm long, 13-25, 19 µm wide at base, 6-8, 7 µm wide in middle, 12-17, 15 µm wide at apex, without conspicuous apicolateral projection; median pit smaller than distal distinct pit and positioned a little proximal. Inferior volsella blunt with a low projection to posterior, not pointed, not reaching beyond anal tergite margin, and covered by microtrichia. Gonocoxite 88-118, 107 µm long, with 3-4, 3 strong medial setae. Gonostylus 158-213, 187 µm long, slender, curved and parallel-sided, with distinct expansion in distal 1/3, bearing 4-7, 6 (8) setae along distal inner margin. HR 0.49-0.68, 0.59, HV 1.63-2.01, 1.80.

Distribution.

Palaearctic ( Spies 2000). It also is recorded from Palaearctic China and Japan. The record for China is new.