Spilogona trianguligera Zetterstedt 1838

Spilogona trianguligera (Zetterstedt, 1838)

(Figs 6–9)

Anthomyza trianguligera Zetterstedt, 1838: 680. Type locality: ‘Lapponia’ in part [= Thynaes, Norway], as restricted by Ringdahl (1939: 144).

Aricia trianguligera (Zetterstedt); Zetterstedt, 1845: 1466.

Limnophora (Spilogona) insularis Collin, 1921: 167, 266. Type localities: Isle of Arran and Nairn, Scotland; ‘ Faröe Islands’ [= Narvik, Norway, see Pont (1995: 90)]. Collin 1930: 278, pl. XVIII: fig. 35, XXVI: figs 35a–d. Tiensuu, 1936: 37, Finland and Murmansk. Synonymy first proposed by Ringdahl (1939: 144), endorsed by Hennig (1959c: 352).

Limnophora (Spilogona) setinervis Huckett, 1932: 64, 72, 155. Type locality: Yakutat, Alaska. Syn. nov.

Spilogona trianguligera (Zetterstedt); Hennig, 1959c: 352, pl. X: fig. 206, XVII: fig. 350 (not 351 as stated in the text and figure legend!).

Spilogona setinervis (Huckett, 1932); Huckett, 1965: 196, 205, 247.

Recently, VM found 1 male Spilogona in a sample of muscoid Diptera from Jameson Land on the east coast of Greenland, that evidently did not belong to any of the 22 species of Spilogona previously recorded from Greenland (Michelsen, 2006). In Huckett (1932, 1965) it keyed out as the species currently known as Spilogona setinervis (Huckett). It agreed well with Huckett’s original description, including the notable presence of a v setula on proximal part of subcosta. The presence of 1–4 setulae on ventrobasal part of subcosta is not, as far as we know, seen in other species of Spilogona. Unfortunately, occasional females of S. setinervis are without these setulae and this is the reason why Huckett (1965) no longer used this character in his key to female Spilogona. In European keys to Spilogona (Collin 1921, Hennig 1959a, d’Assis-Fonseca 1968) the Greenland male keyed out as the species currently known as Spilogona trianguligera (Zetterstedt). Our Palearctic material of that species consists of 2 males 4 females from the Faroe Islands, Scotland, Norway and Russia (Altai Mts). These specimens all possess 1– 4 v setulae on subcosta basad of the humeral cross-vein except for 2 females having a small subcostal setula on one wing only. Evidently, this character has till now been overlooked by European muscid specialists, one possible reason why the synonymy of Spilogona setinervis and S. trianguligera has remained unnoticed. A further reason is that there exist no published illustrations of the male terminalia of Spilogona setinervis in the literature on Nearctic Muscidae.

See Pont (2011: 60) for details on the type material of Anthomyza trianguligera Zetterstedt. Details about the type material (syntypes, 6 males 4 females) of Limnophora (Spilogona) insularis Collin are given by Pont (1995: 90). Holotype male of Limnophora (Spilogona) setinervis Huckett, in the National Museum of Natural History, Washington DC according to Huckett (1932: 157), not examined by us.

The only published illustrations of the male terminalia of S. trianguligera are those of Collin (1930) based on a specimen from Scotland. They were also used in part by Hennig (1959c). The present illustrations (Figs 6–9), based on the only male specimen available from Greenland, agree in all essential aspects with Collin’s excellent drawings. This also holds for a male from Canada (Manitoba) dissected by VS. We thus conclude that Spilogona setinervis (Huckett, 1932) is a new junior synonym of Spilogona trianguligera (Zetterstedt, 1838).

Material examined. CANADA: Manitoba: Churchill, Goose Creek Rd., Pump House, 58.63ºN 94.23ºW, Malaise trap, 2 males 2 females, 3–21.vii.2007, leg. A. Renaud (SZMN). GREENLAND (NE): Jameson Land, Colorado Dal, 1 male, 25–27.vii.2001, leg. H. Björnsson (ZMUC). FAROE IS: Suduroy: Tvaerå [=Tvøroyri], 2 females reared 1.xii.1926 ex larvae found 7.vii.1926, leg J. P. Kryger (ZMUC). SCOTLAND: Shetland Is., E Mainland, Vidlin, stream, 2 males, 17–18.vi.1993, leg. B.R. Laurence (SZMN). NORWAY: NE Nordland: Narvik, 1 female, 1.vii.1918, leg. O. Ringdahl (ZMUC). RUSSIA: Respublika Altai: Ulagan region, environs of Dzhulukul’ lake, 2200 m, 50.47ºN 89.77ºЕ, 1 female, 21.vii.2007, leg. V. Sorokina (SZMN).

Distribution. Northern Holarctic (boreal to low arctic): USA (Alaska), Canada (Yukon Territory, Northwest Territories, Nunavut, Manitobia, Quebec, Newfoundland and Labrador), Greenland (NE), Faroe Islands, Great Britain (England, Scotland), Norway, Finland, Russia (Murmansk, W Siberia: Altai). New records for Greenland and W Siberia.