DragonflyPix

Toendraglanslibel (Somatochlora sahlbergi)

• Scientific name: Somatochlora sahlbergi Trybom, 1889
• English name: Treeline Emerald
• German name: Polar-Smaragdlibelle
• French name: N/A
• Dutch name: Toendraglanslibel
• Swedish name: Tundratrollslända
• Norwegian name: Nordlig metalløyenstikker
• Finnish name: Tundrakiiltokorento
• Danish name: N/A
• Italian name: N/A
• Czech name: N/A
• Slovenian name: N/A
• Bulgarian name: N/A
• Typical length: 48-50 mm
• Hindwing: 30-33 mm

Toendraglanslibel (Somatochlora sahlbergi)

Distribution map

Map data based on J.-P. Boudot & V. J. Kalkman (eds.),
Atlas of the European Dragonflies and Damselflies

The Treeline Emerald has a so-called circumboreal distribution; it occurs north of the arctic circle in Canada, Alaska, Siberia, Russia and Northern Europe. It is perhaps the least studied and least understood of our dragonfly species for two reasons: it occurs in remote tundra habitat which may be difficult to reach and where weather conditions are notoriously fickle, and the species is best described as a 'reluctant flier', in that it very rarely betrays its presence through flight, preferring instead to sit on top of the low vegetation and to stay put. At the third time of asking, and having combed the Finnish and Swedish tundra for 15 very long days, we finally managed to see and photograph one single individual in July 2013. Somatochlora sahlbergi looks very similar to its twin species, the Alpine Emerald (Somatochlora alpestris). The principal differences consist in the more sharply angular shape of the male's appendages, the shape of the female's vulvar scale (elongate and tapered in S. sahlbergi as opposed to triangular in S. alpestris), and - more readily observable in the field - the presence of a single cubito-anal crossvein in the forewing (as opposed to the, unusual, two crossveins in S. alpestris).

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