First record of extra-abdominal processes in adult Odonata

Abstract

Paired extra-abdominal processes (ap) were found in the pleural region of abdominal segments 6–9 in adult Odonata for the first time. They are unsegmented bulge-like or rod-like structures of different size, degree of sclerotization and movability. A short search across odonatan families has shown that ap are inherent for all studied Aeshnidae and for some other Anisoptera. A comparative study of final stadium larvae has shown that ap appear as remnants of larval lateral spines originally situated on larval tergites. This fact provides evidence about the complex nature of the pleural region in the Aeshnidae imago which includes part of the area of the larval tergite.

Keywords: comparative morphology, homology, appendages, abdomen, heterochrony, Odonata, dragonfly

Issue section: Review