Genus Heliaeschna Selys, 1882
swamp duskhawkers

Type species: Heliaeschna fuliginosa Selys, 1883

Introduction

Five species inhabit tropical Africa, while several probably unrelated Oriental species are also placed in Heliaeschna. Habits, appearance and small to large size (hindwing 35-54 mm) are like Gynacantha, although Heliaeschna is more localised and seems partial to swampy forest. Most species range from Uganda and northern Zambia to western Africa, H. trinervulata also to northern Malawi. The largest species, H. fuliginosa, is encountered most often, patrolling deeply shaded wet spots with thick leaf litter, especially later in the day. Identification and taxonomy remain difficult: separating H. sembe, H. trinervulata and H. ugandica males may sometimes be impossible. In all species, thorax and abdomen base are green, the remainder of abdomen blackish, and legs reddish brown, often with blackened tibiae and tarsi. The smaller species have green spots on abdominal segments 2-8, the larger black lines on the thorax sutures. [Adapted from Dijkstra & Clausnitzer 2014]

Diagnosis

Male of genus is similar to Gynacantha by (a) frons at most 2/5 as wide as head (dorsal view); (b) auricles present; (c) IR3 clearly forked proximal to Pt; (d) IR2 usually extends proximally more than halfway under Pt; (e) R3 not or only weakly arched forward near distal end of Pt; (f) distal end of Rspl directed at wing tip or point posterior of it; (g) Hw tornus angled; (h) Hw cubital field often of 1 cell-row at base; (i) membranule small, only touching extreme base of anal triangle; (j) anal triangle present; (k) anal triangle falls short of tornus by at least 1/3 of its length. However, differs by (1) 3-7 cross-veins in median space of all wings; (2) 1-2 secondary Ax present proximal to proximal primary Ax; (3) mainly 2 cell-rows in fork of IR3, rather than 2-5 rows; (4) brace veins always absent. [Adapted from Dijkstra & Clausnitzer 2014; this diagnosis not yet verified by author]

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.


References

  • Fraser F.C. (1939). Heliaeschna cynthiae, a new species of dragonfly from Uganda (Order: Odonata). Proceedings of the Royal Entomological Society of London (B), 8, 88-90. [PDF file]
  • Dijkstra, K.-D.B. (2005). Taxonomy and identification of the continental African Gynacantha and Heliaeschna species (Odonata: Aeshnidae). International Journal of Odonatology, 8, 1-32. [PDF file]
  • Dijkstra, K.-D.B, and Clausnitzer, V. (2014). The Dragonflies and Damselflies of Eastern Africa: handbook for all Odonata from Sudan to Zimbabwe. Studies in Afrotropical Zoology, 298, 1-264.
  • Longfield, C. (1936). Studies on African Odonata, with synonymy and descriptions of new species and subspecies. Transactions Royal Entomological Society London, 85, 467-498. [PDF file]
  • Schouteden, H. (1934). Annales Musee Congo belge Zoologie 3 Section 2, 3, 1-84. [PDF file]

Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2017-08-19].