Genus Ceratogomphus Selys, 1854
thorntails

Type species: Ceratogomphus pictus Hagen in Selys, 1854

Introduction

Endemic to southern Africa with only two species. C. triceraticus is confined to the Cape, while the smaller and paler C. pictus is widespread from South Africa to Zimbabwe, with a single isolated record from Katanga. Both species inhabit open and calm pool-like sections of streams and rivers, and often perch on the ground or rocks. C. picta also easily colonises impoundments, which is unusual for gomphids. The latter is a medium-sized (hindwing 28-30 mm) dragonfly with milky thorax bands and yellow costa contrasting with black pterostigma that recall Crenigomphus, but the modified abdominal segment 10, foliation on segment 8 only and distinct anal loop suggest Phyllogomphus is the genus’ nearest relative. [Adapted from Dijkstra & Clausnitzer 2014]

Diagnosis

Male of genus is similar to Phyllogomphus by (a) dorsal border of metepisternum without spine; (b) Hw base broad with distinct anal triangle of 3-6 cells, tornus angular and without thick tooth; (c) distinct anal loop of 4-5 cells; (d) posterior hamules large, often overlapping with posterior lamina; (e) S8 with foliations, S9 without; (f) S10 usually not longer than high, if so it has dorsal crest or is constricted at base; (g) S10 with longitudinal dorsal ridge, marked by denticles or blade-like basal process. However, differs by (1) dorsal ridge S10 without denticles, drawn out to basal blade, accommodated by sheath-like cleft on S9; (2) cerci stout rather than elongate, and touching each other at apex (dorsal view). [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

• Ris, F. (1921). The Odonata or Dragonflies of South Africa. Annals South African Museum, XVIII, 245-452. [PDF file]
• Balinsky, B.I. (1963). A contribution towards the systematics of dragonflies of southern Africa (Odonata). Journal Entomological Society Southern Africa, 26, 228-255. [PDF file]
• Pinhey, E.C.G. (1961). Dragonflies (Odonata) of Central Africa. Occasional Papers Rhodes-Livingstone Museum, 14, 1-97. [PDF file]
• Barnard, K.H. (1937). Notes on dragon-flies (Odonata) of the S. W. Cape with descriptions of the nymphs and of new species. Annals South African Museum, 32, 169-260. [PDF file]

Citation: Dijkstra, K.-D.B (editor). African Dragonflies and Damselflies Online. http://addo.adu.org.za/ [2024-11-15].