Genus Allocnemis Selys, 1863
- scientific: Chlorocnemis Selys, 1863 [elongata]; Isomecocnemis Cowley, 1936 [cyanura]
Type species: Platycnemis leucosticta Selys, 1863
Aside from the relative length of the anal vein, Allocnemis, Chlorocnemis and Isomecocnemis are similar and cannot be separated genetically, so we consider all as one genus. Eighteen species are all endemic to Africa. Males are sleek, fairly large (hindwing 20-28 mm) and largely black damselflies with yellow to deep amber wings and bright accents of colour (mainly pale blue or orange), e.g. on abdomen tip. Moving spots of colour often first draw attention in the gloom of their habitat, small streams and springs in deep forest shade. The genus is most diverse in the rainforests of western and central Africa. Four species occur locally in forest fragments in the mountains from southern Kenya to Mozambique: A. montana is known only from two sites at 1800-2000 m in the Tanzania-Malawi border region; A. maccleeryi only around 1500 m on Mt Ntchisi a bit further south. A. abbotti and A. marshalli are more widespread, but none of these montane species appear to overlap. A. leucosticta with it distinctive white pterostigmas has the widest habitat range, occurring even at rather open rocky rivers, but is confined to South Africa. Of the other species, up to four may occur in close proximity, but ecological differences are poorly known. For example, A. elongata, A. flavipennis and A. subnodalis are almost invariably found together in Western Africa. Similarly A. contraria, A. nigripes, A. pauli and/or A. superba may be found together at streamlets in Central Africa, but the first prefers somewhat larger streams, the second ranges from seeps to streams, while the co-occurring A. cyanura is partial to springs with much leaf litter. Most species are found in the Lower Guinea, with endemics A. eisentrauti, A. interrupta and A. vicki. A. wittei and A. mitwabae are known only from Katanga and adjacent Zambia, the latter only from the Kibara and Kundelungu Plateaus. Coloration is most important for identification, which must rely on mature males. Orange may be almost luminescent in life, sometimes deep red, but becomes pale yellow after death. Moreover, at least in freshly emerged A. contraria and A. nigripes all orange markings are blue. The term ‘pale’ is used to indicate any unspecified non-black colour. [Adapted from Dijkstra & Clausnitzer 2014]
However, differs from other coenagrionoid genera with (a) head very wide, about 3x as broad as deep; (b) quadrilaterals rectangular, in Fw anterior border about 3x as long as distal border; (c) 2 cells between quadrilateral and subnode, although rarely 3; by (1) wings often yellow rather than clear; (2) R4 originates closer to subnode than IR3; (3) Cux stands at origin of anal vein. [Adapted from Dijkstra & Clausnitzer 2014]
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.
- Dijkstra, K.-D.B. (2007). The name-bearing types of Odonata held in the Natural History Museum of Zimbabwe, with systematic notes on Afrotropical taxa. Part 2: Zygoptera and species descriptions. International Journal of Odonatology, 10, 137-170. [PDF file]
- Ris, F. (1921). The Odonata or Dragonflies of South Africa. Annals South African Museum, XVIII, 245-452. [PDF file]
- 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]
- 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]
- Pinhey, E.C.G. (1967). Odonata Zygoptera. Exploration Hydrobiologique Bassin Lac Bangweolo Luapula, 14, 1-43. [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/ [2020-05-30].