Heleodromia irwini Wagner

Heleodromia irwini Wagner

Heleodromia irwini Wagner, 1985: 37. Type locality: Scotland, Moray, Dorback Burn, UK.

Other references: Sinclair et al., 2011: 641 (revision, redescription); Shamshev, 2016: 17 (checklist).

Material examined. RUSSIA. Chukotka AO (Wrangel Island): middle flow of river Neozhidannaya, 71°01′N 179°09′E, YPT, BT 4, 12–16.vii.2016, LFV (1 ♂, ZIN).

Recognition. Small greyish delicate flies (body length 3–3.5 mm) with very slender legs almost lacking distinct setae, eyes dichoptic in both sexes, separated by broad V-shaped flattened frons; legs black to reddish brown, “knees” often somewhat paler; habitually very similar to H. pullata (Fig. 2, see below). Male terminalia large, reniform; tergite 8 not broader than sternite 8, only produced medially as a shallow bilobed to forked projection and lacking posterolateral projection (Sinclair et al. 2011: 641, fig. 10); epandrial lobe slender, finger-like, bearing apical seta; surstylus slender, finger-like, with scattered setae, with small preapical thumb-like projection medially; apex with short dentiform process; phallus with slender, needle-like apex.

Distribution. Holarctic. The distribution of this species appears to be represented by widely disjunct populations exhibiting boreo-alpine connections in Europe and North America (Plant 2005; Plant et al. 2017; Sinclair et al. 2011). Our record of H. irwini from Wrangel Island may support this suggestion. In Eurasia, this species is known from Austria, Germany, Italy, Switzerland, Scotland and the Far East of Russia (Amurskaya and Magadanskaya Provinces); in North America, it is recorded from western part of Canada and USA. It seems that H. irwini is found here for the first time from the tundra zone.

Habitat. The species was collected in wetlands in a river valley.