Genus Oxygastra Selys, 1870
orange-spotted emeralds

Type species: Cordulia curtisii Dale, 1834

Introduction

For an introduction to this genus, please refer to: Dijkstra, K.-D.B. & R. Lewington, 2006. Field guide to the Dragonflies of Britain and Europe. British Wildlife Publishing. 1-320.

Diagnosis

A dark, slender emerald easily identified by the combination of the brilliant green eyes and the deep yellow streaks on the upperside of the dark, slender, clubbed abdomen. Males patrol short stretches of calm, tree-lined rivers. The only species of its genus worldwide, its venation and appendages are unique among North Afican dragonflies. Face all dark metallic. Thorax is metallic green, loosely covered with short hairs. Wing bases with rather extensive areas of saffron; in female, this extends along the leading edges of the wings. Abdomen is dark metallic green, with a chain of orange-yellow spots on the upperside of S1-7 and S10. Male S10 bears a yellowish membranous crest on the upperside. Male’s upper appendages are blunt and somewhat divergent (seen from above), each with an elongate ventral spine near the base (seen from side). Lower appendage with a broad, notched tip (seen from below). Female’s appendage is short, vulvar scale tiny, almost invisible. Venation differs from other corduliids: (1) anal loop consists of two long arched rows of cells, not foot-shaped; (2) hindwing triangle is distinctly separated from arculus and shifted towards the wing tip; (3) membranule is all whitish, not dark-tipped; (4) anal angle of male hindwing is rounded, less angular. [Adapted from Dijkstra & Lewington 2006]

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

  • Dijkstra, K.-D.B., and Lewington, R. (2006). Field guide to the Dragonflies of Britain and Europe. British Wildlife Publishing.,1-320.

Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2017-03-26].