New Data on the Olistheter Structure in Dragonflies and Damselflies (Odonata)

Examination of cross-sectional images of gonapophyses in the damselflies Calopteryx splendens (Harris, 1780) (Calopterygidae) and Coenagrion hastulatum (Charpentier, 1825) (Coenagrionidae), has shown that they possess a typical non-detachable olistheter that is found in all Pterygota with a normally developed primary ovipositor. The new data suggest that the non-detachable olistheter of the type discovered in Odonata may be a synapomorphy of Pterygota excluding Ephemeroptera.