Enallagma cyathigerum (Charpentier, 1840)
Common Bluet

Type locality: Silesia, Europe

Diagnosis

One of many bluets whose identity is best confirmed in the hand. Easily identified by the black markings, e.g. the “mushroom” on the male’s S2, the “torpedoes” on female’s S3-7 and the “single stripe” on the thorax sides of both. Size and shape close to other bluets, but appears slightly robuster and purer blue. Combines the following markings: (1) Broad antehumeral stripes and large postocular spots in both sexes, the antehumeral is normally at least as wide as the black humeral stripe beneath it. (2) The sides of the thorax appear plain because usually there isn’t a short black stripe stripe between the humeral stripe and the small black stripe on the lower suture. (3) The male has a small mushroom-like figure on S2 and S8-9 are completely blue, creating a conspicuous ‘tail-light’. (4) The female has black torpedo-like markings on the abdominal dorsum. Erythromma lindenii males share the skimming habit and broad antehumeral of E. cyathigerum, but the postocular spots are reduced, there are two short black stripes on the thorax sides, the entire dorsum of S2 is black and the blue is shifted to S9-10 (S8 is black). Coenagrion males are hardly distinguishable at a distance, but prefer to remain amongst bankside vegetation. They have antehumerals narrower than the humeral, the two short thorax stripes and a different marking on S2 (but see variation). Aforementioned features of head and thorax also apply to Coenagrion and Erythromma females. A quick look for the female’s vulvar spine with a hand lense rules out confusion with all Coenagrion, Erythromma and Sympecma species! In both sexes the hind marging of the pronotum is only weakly curved, unlike most Coenagrion species, where there are often prominently projecting lobes, especially in females. Contrary to Coenagrion at least one subcostal cell between pterostigma and wing tip in Hw is usually doubled. The male’s S2 mushroom may be round or pointed, its stem may be missing or lateral wing-like extensions can be present. [Adapted from Dijkstra & Lewington 2006]

Habitat description

Standing waters in open landscapes. Often with emergent and aquatic vegetation. Only recorded at around 1400 and 1500 m above sea level.

Distribution

confirmed: Morocco

Map citation: Clausnitzer, V., K.-D.B. Dijkstra, R. Koch, J.-P. Boudot, W.R.T. Darwall, J. Kipping, B. Samraoui, M.J. Samways, J.P. Simaika & F. Suhling, 2012. Focus on African Freshwaters: hotspots of dragonfly diversity and conservation concern. Frontiers in Ecology and the Environment 10: 129-134.


Reference

  • Charpentier, T. de (1840). Libellulinae Europaeae Descriptae et Depictae. Leopold Voss, Lipsiae, 1-180.

Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2020-10-21].