Extant odonates (damsel- and dragonflies) represent a small subset of the historical biodiversity of this group. Among their successive stem-groups, the Triadotypomorpha are poorly documented. Herein we describe a new species Reisia rieki from the Molteno Formation (South Africa, Upper Triassic) belonging to this taxon. The comparatively large sample allows a relatively complete description of the wing venation in Triadotypomorpha. We noticed the occurrence of a strongly oblique crossvein located between RA and RP1, a condition documented in some other Pandiscoidalia and which might be of phylogenetic importance. The new species probably inhabited open landscapes and foraged above large water bodies. The documentation of a Gondwanian Triadotypomorpha demonstrates that the group had a worldwide distribution by the Triassic.

Key words: Arthropoda, Odonata, Pandiscoidalia, Triassic, Carnian, Molteno Formation, South Africa.

Isabelle Deregnaucourt [isabelle.deregnaucourt@edu.mnhn.fr] and Olivier Béthoux [obethoux@mnhn.fr] (corresponding author), Sorbonne Universités, UPMC Univ Paris 06, MNHN, CNRS, Centre de recherche sur la paléontologie-Paris (CR2P), 57 rue Cuvier, CP38, F-75005 Paris, France. Torsten Wappler [xtwappler@uni-bonn.dexx], Steinmann Institute, University of Bonn, Nussallee 8, 53115 Bonn, Germany; and [wappler@hlmd.de], Hessisches Landesmuseum, Friedensplatz 1, 64283 Darmstadt, Germany. John M. Anderson [jmanderson.gondwana@gmail.com], Environmental Studies Institute, Witwatersrand University, 1 Jan Smuts Ave., Braamfontein, Johannesburg 2000, South Africa.