Rhamphomyia (Eorhamphomyia) shewelli Sinclair, Vajda, Saigusa & Shamshev

Rhamphomyia (Eorhamphomyia) shewelli Sinclair, Vajda, Saigusa & Shamshev

(Fig. 26)

Rhamphomyia (Eorhamphomyia) shewelli Sinclair et al., 2019: 29. Type locality: Coral Harbour, Southampton Island, Canada.

Material examined. RUSSIA. Chukotka AO (Wrangel Island): middle flow of Mamontovaya River, N of Perkatkun, osier-bed in river valley, 17.vii.1972, KBG (1 ♀, ZIN); same locality, 71°10′N 179°45′W, BT 3, 29.vi.–9.vii.2006, OAK (1 ♂, ZIN); same locality and biotope, 9.vii.2006, OAK (1 ♀, ZIN); same locality and biotope, 1.vii.2015, leg. OAK (3 ♀, ZIN); same locality, BT 1 А, 2.vii.2015, OAK (1 ♂, ZIN); same locality, BT 20 А, 2–4.vii.2015, OAK (2 ♂, ZIN); same locality, 71°10′N 179°45′W, BT 7, 1.vii.2015, OAK (1 ♂, ZIN); upper flow of river Neizvestnaya, 71°13′N 179°19′W, BT С1, 24.vi.2015, OAK (1 ♀, ZIN); same locality, BT 7 А, 25.vi.–10.vii.2015, OAK (1 ♀, ZIN); middle flow of Neizvestnaya River, 71°20.287′N 179°29.779′W, BT 1, YPT, 5–14.vii.2018, U. V. Babiy (1 ♀, ZIN); same locality, 71°20.416′N 179°29.651′W, BT 2, YPT, 13–14.vii.2018, U. V. Babiy (3 ♂, 2 ♀, ZIN); same locality and biotope, YPT, 4–5.vii.2019, U. V. Babiy (4 ♂, 4 ♀, ZIN).

Recognition. Mid-sized (wing length 4.7–5.3 mm) blackish species. Male (Fig. 26) holoptic; thorax black setose, scutum with pair of pruinescent vittae anteriorly, sometimes lustrous posteriorly; supra-alar region with broad shiny stripe, mesonotal setae well differentiated, presutural dc 3–4-serial, acr biserial, 6–8 sctl (rarely 10); legs slender, entirely dark brown, no modified podomeres, hind femur with minute anteroventral setulae (except several longer setae near extreme base), all tibiae with rows of long ad and pd setae; wing faintly infuscate, axillary incision very acute, at most 45°, halter yellow; abdomen pruinose dorsally and narrowly shiny laterally; phallus short, almost entirely hidden within epandrium and cerci, at most very short portion between lower margin of epandrium and hypandrium visible, hypandrium well exposed, subtriangular. Female with somewhat darker wing, legs without pennate setae. Besides the species noted in the key, R. shewelli should be compared primarily with R. dorsata Becker known from Arctic continental territories of Eurasia. However, in the latter species the scutum is broadly shiny laterally leaving only a very narrow greyish vitta beneath the acrostichals and the abdomen is entirely shiny in dorsal view (Sinclair et al. 2019).

Distribution. Holarctic; in North America, this low arctic species is widespread across western and central arctic region (Sinclair et al. 2019); in Eurasia, it is known only from Wrangel Island.

Habitat. On Wrangel Island this species was collected only in the warmer central part of the island. The majority of specimens were found in wet habitats with willow bushes, located in river valleys.