Genus Zyxomma Rambur, 1842
duskdarters

Type species: Zyxomma petiolatum Rambur, 1842

Introduction

Several species occur in tropical Australasia, of which Z. petiolatum reaches the Seychelles and Mascarenes: a single species is endemic to continental Africa. Z. atlanticum is a medium-sized (hindwing 30-34 mm) species, with a brown body, slender abdomen, and big pale green eyes with three transverse dark stripes. The wings are normally distinctly smoky or yellow-stained, especially around the nodes and pterostigmas and at the hindwing base. It swiftly patrols low over pools in swampy forest when it is almost dark and rests low in undergrowth during the day, recalling a miniature Gynacantha with its large eyes, long body and dull colours. The species occurs from Uganda through the Congo Basin to western Africa, with an isolated population on the north-eastern South African coast. [Adapted from Dijkstra & Clausnitzer 2014]

Diagnosis

Male of genus is similar to Tholymis by (a) hindlobe of prothorax small, roughly semicircular and widest at base (dorsal view), apex often pressed downwards (lateral view), its border with short hairs and at most a few longer hairs; (b) Pt in both wings of similar size; (c) Fw triangle points approximately to distal apex of Hw triangle; (d) subtriangle distinctly closed, of 1-3 cells; (e) Fw anal field at arculus of 2 rows; (f) anal loop usually open on wing border; (g) wing markings usually less extensive or intense, or stronger on Hw, and never with brown postnodal bands; (h) S4 with transverse ridge of similar strength as that on S3 and lateral carina S4. However, differs by (1) 12½-15½ Ax in Fw; (2) bridge spaces with 2-3 cross-veins, rarely 1; (3) both wings clear or evenly smoky, white marking absent; (4) 1 row in radial planate, rarely 2; (5) Abd longer than Hw, S4 distinctly waisted. [Adapted from Dijkstra & Clausnitzer 2014]


Zyxomma atlanticum Selys, 1889. Male © Dirk Motshagen


Zyxomma atlanticum Selys, 1889. Male © Warwick Tarboton

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

  • 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.
  • 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/ [2017-03-24].