Skimmers

Family Libellulidae      (Leach, 1815_

• Genus Orthetrum     (Newman, 1833)

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

Learn more about the different Skimmer Species 

Distribution