Parachironomus subalpinus

Parachironomus subalpinus (Goetghebuer, 1931)

(Figs 22–30)

Cryptochironomus subalpinus Goetghebuer, 1931; Lehmann (1970: 105–151, fig. 16); Oliver & Dillon (1997: 625); Langton & Pinder (2007: 112, fig. 221 D).

Parachironomus spissatus Brundin, 1949: 54, figs 84–84.

Material. male, Russia, Chukotka Autonomous Region, basin of Khatyrka River, Myssovye Lakes, 27.vii.1980, leg. E. Makarchenko.

Male imago (n=1). See also Table 5.

Total length 4.2 mm.

Coloration. Scape brown; ground color of thorax brown, mesonotal stripes and postnotum dark brown; abdomen and legs brown.

Head. Frontal tubercles absent. Temporal setae 18/20. Clypeus with 20 setae. Antenna lost. Maxillary palpomeres 2–4 combined 605 µm long, their individual lengths (in µm): 51; 163; 173; 218.

Thorax. Antepronotals 8/9, acrostichals 16, dorsocentrals 22/25, prealars 6, supraalars 1. Scutellum with 23 setae.

Wing. Length 2.28 mm, without microtrichia. VR 1.10. R with 23, R1 with 21, R4+5 with 25 setae in distal 2/3, M1+2 with 8 setae. Squama with 12 setae.

Legs. See Table 3. Each mid and hind tibia with 2 fused combs and 2 short spurs (length 10 µm). BR P2 3.5. Fore and hind tarsomeres lost from the specimen.

Hypopygium (Figs 22–30). Laterosternite IX with 2/3 setae. Anal tergite without median longitudinal band, but with well developed triangular ventrolateral shoulders on posterior margin. Anal point in dorsal view length 99 µm, apical parallel-sided free section length 41 µm; in lateral view the base is narrow (17 µm), carries microtrichia and 3–4 lateral setae, and 6–7 lateral setae at the base of the anal point, apical part narrow and angled to ventral. Portal setae 3 on each side. Gonocoxite 153 µm long, with 4 setae on inner margin. Transverse sternapodeme 98 µm long. Phallapodeme 119 µm long. Superior volsella (112–116 µm long) straight in both, dorsal and lateral views, little to moderately expanded at the base, apically with lamellar projection (14 µm) as wide as apex of volsella, with 1 terminal seta (23 µm) located in 10–14 µm wide pit and 1 medial seta (24 µm) located in 8.5–10 µm wide pit, distance between setae 10 µm. Inferior volsella with small prominence to median or posterior, its microtrichia not elongate. Gonostylus 218 µm long, in dorsal view almost straight, proximal part bears 6 latero-ventral setae, distally adjacent section narrower and bare or with 1 seta; in lateral view gonostylus strongly expanded in the middle (up to 54 µm high) and gradually tapering, with a row of 6 distal-median setae. HR 0.69.

Remarks. Far Eastern specimens of P. subalpinus do not appear to differ from western European specimens in hypopygium structure or morphometric indices.

Distribution. Holarctic species. Previously known from western Europe (Austria, Finland, Germany, Ireland, and Sweden; Saether & Spies 2013) and from Canada (Yukon Territories; Oliver & Dillon 1997). Recorded for the fauna of Russia for the first time here.