Skimmers

Family Libellulidae      (Leach, 1815_

Worldwide
  • In the Old World over 80 species.
  • About 50% in Africa
Southern African Region
  • 1 genus (Orthetrum) and 15 species
Habitat
  • Common and conspicuous at most freshwater habitats, especially when these are open 
  • Many can be found almost anywhere in tropical Africa, although they tend to prefer (or are dominant in) certain habitats
  • Refer to African Dragonflies & Damselflies Online  for an analysis of species or groups of species per habitat
    The knowledge of preferred habitat will greatly assist in the identification of a species 
General information:

The correct identification of Skimmers, are not easy. Mature male acquire a greyish sheen.  This sheen masks the colours and markings visible when immature.

  • All male skimmers are blue/grey (pruinnosity) with age. The Long Skimmer O. Trinacria  does not pruinose
  • Mature males appear very similar due to their blue-grey pruinosity, obscuring all coloration and markings.
  • Many species differ by markings, but these get obscured by pruinosity as the males grow older.
  • Females and young males are similar in colour and markings. Most are yellow to brown with distinctive black markings
  • Turquoise eyes with whitish face is characteristic. The Long Skimmer O. trinacria has blue eyes with brownish face.
  • Size range, from small to very large (hindwing 22-50 mm)
    • In hand it is useful to inspect
    • Size (length and wingspan)and compare with given data
    • Length of pterostigmas (unusually long or short)
    • Wing venation and vein colours
    • With young males or females, compare thorax and abdomen markings
    • Where possible the shape of secondary genitalia
  • Distinguishing Orthetrum species is often considered difficult
Identification aid
  • Assess the size (length and wing span and pterostigmas)
  • The subcostal sections of Ax can be dorsally dark (like the costal sections) or pale (normally visible on a good image)
  • The number of doubled cells in the radial planate (count those cells touching Rspl, but not IR3) may differ between species
  • Check the male’s secondary genitalia to confirm identification. Compare the profile of the anterior lamina, genital lobe, inner and outer hamules with known examples
Synopsis
  • Only males are shown
  • To view females follow the menu links to the species description page
Images of the different Skimmer Species 
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