Parachironomus frequens (Johannsen)

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 : 33-34

Taxon classification Animalia Diptera Chironomidae

Parachironomus frequens (Johannsen) Figs 1-4

Chironomus frequens Johannsen, 1905: 230. - Malloch (1915: 452).

Chironomus (Cryptochironomus) lhoneuxi Goetghebuer, 1921b: 168.

Cryptochironomus longiforceps Kieffer, 1921d: 66.

Harnischia (Harnischia) frequens (Johannsen). - Townes (1945: 155).

Parachironomus frequens (Johannsen). - Lehmann (1970: 143); Pinder (1978: 132).

Parachironomus toneabeus Sasa & Tanaka, 1999: 38, syn. n.

Parachironomus kamaabeus Sasa & Tanaka, 2001: 45, syn. n.

Material examined.

CHINA: 1 male, Hebei Province, Zunhua City, Dongling, Longmenkou Reservoir, 7. vii. 2001, Y. Guo; 1 male, Yunnan Province, Kunming City, Yiliang County, 2. vi. 1996, X. Wang; 1 male, Xizang Autonomous Region, Nyalam County, Zhangmu Town, 2400 m, a. s. l., 16. viii. 1987, light trap, C. Deng.

JAPAN: Holotype of Parachironomus kamaabeus Sasa & Tanaka, 2001 (No. 391: 45), male, Gunma Prefecture, Tone River, Taisho Bridge, light trap, 1. vii. 1999. -Paratype of Parachironomus kamaabeus Sasa & Tanaka, 2001 (No. 391: 47), male, Gunma Prefecture, Tone River, Taisho Bridge, light trap, 3. vii. 1999.

Diagnostic characters.

The species is distinguished by the following combination of characters: mid and hind legs with dark brown rings, tergite IX with shoulder-like caudal margin; basal half of anal point with lateral setae, superior volsella finger-like.

Redescription

(Chinese specimens). Male imago (n=3, unless otherwise stated). Total length 4.15-4.70, 4.46 mm. Wing length 1.98-2.54, 2.33 mm. Total length / wing length 1.78-2.10, 1.93. Wing length / length of profemur 2.20-2.47, 2.37.

Coloration. Thorax yellowish green to yellowish brown. Femora and tibiae of front legs yellowish green with distal 1/3 of tibiae and tarsi I dark brown, tarsi II with distal dark brown rings, tarsi III–V dark brown; femora and tibiae of mid and hind legs yellowish green, tarsi I, II of mid legs and tarsi I–III of hind legs pale with distal dark brown rings, tarsi III–V of mid legs and tarsi IV, V of hind legs completely dark brown (Fig. 1). Abdomen yellowish green to yellowish brown.

Head. AR 2.66-2.86, 2.79. Terminal flagellomere 850-1030, 960 mm long. Frontal tubercles absent. Temporal setae 16-17, 17, including 3-4, 4 inner verticals, 7-9, 8 outer verticals and 5-6, 5 postorbitals. Clypeus with 19-26, 22 setae. Tentorium 100-150, 133 mm long, 40-50, 47 mm wide. Palpomere lengths (in mm): 37-55, 47; 55-68, 59; 145-220, 184; 160-213, 181; 178-338, 255. Length ratio 5th /3rd palpomere 0.95-1.71, 1.40.

Thorax. Antepronotals 3-5 (2), acrostichals 5-9 (2), dorsocentrals 10-12 (2), prealars 5-9 (2). Scutellum with 18-20 (2) setae.

Wing (Fig. 2). VR 1.16-1.18, 1.17. R with 20-25, 22 setae, R1 with 20-21, 21 setae, R4+5 with 22-26, 24 setae. Brachiolum with 3-4, 3 setae. Squama with 13 setae.

Legs. Front tibia with 3 subapical setae, 110 (1), 138-140 (2) and 150 (2) µm long; spurs of mid tibia 28-48, 36 and 33-50, 41 µm long, comb with 40-56, 47 teeth, 10-15, 12 µm long; spurs of hind tibia 33-55, 42 and 42-75, 56 µm long, comb with 56-68, 62 teeth, 10-15, 12 µm long. Tarsus 1 of mid leg with 22 sensilla chaetica, hind legs without sensilla chaetica. Lengths (in µm) and proportions of legs as in Table 1.

Hypopygium (Figs 3, 4). Laterosternite IX with 7-8 (2) setae. Anal tergite bands Y-shaped, fading far apart medially. Tergite IX with shoulder-like margin, bearing 2 setae at base of anal point. Anal point originating from caudal margin of anal tergite, bearing 14-22, 17 lateral setae in basal half, widened at base, constricted medially, slightly swollen apically, 130-155, 143 mm long, 30-35 (2) mm wide at base, 8-12 (2) mm wide in middle, 14-15 (2) mm wide at apex. Transverse sternapodeme 40-50, 46 mm long. Phallapodeme 95-118, 107 mm long. Superior volsella slightly curved, finger-like, slender distally, with an apical seta and a proximal lateral seta, both not arising in conspicuous pits. Inferior volsella with a moderately pointed caudal projection, covered with microtrichia, and reaching beyond anal tergite margin. Gonocoxite 148-175, 158 mm long, with 4-5 (2) strong medial setae. Gonostylus 230-275, 256 mm long with apical hook (2), slightly swollen at base, parallel-sided medially, curved distally, bearing 9-10 (2) setae along the basal inner margin and 12-14 (2) setae along the distal inner margin. HR 0.58-0.64, 0.62; HV 1.64-1.80, 1.74.

Distribution.

Holarctic ( Sæther and Spies 2013). The species is also known from Japan and China; the record for China is new.

Remarks.

Sasa and Tanaka (1999) described Parachironomus toneabeus from Japan based on material collected at Kamakura Bridge, Ino River, Gunma Prefecture on 21 August 1998. The sample number was given as "391: 45 –47”. Sasa and Tanaka (2001) proposed Parachironomus kamaabeus according to material collected at Taisho Bridge, Tone River, Gunma Prefecture on 1 July 1999. However, the number of the specimen is also "391: 45 –47”. Based on the type specimens and the original descriptions and figures, we place both Parachironomus toneabeus and Parachironomus kamaabeus as new junior synonyms of Parachironomus frequens (Johannsen), due to distinct matches in leg color, shapes of the anal point, superior volsella and gonostylus, and the shoulder-like tergite IX margin.