A remarkable new genus and species of dragonfly (Odonata: Anisoptera: Libellulidae) from Brazil and notes on its bionomics and phylogenetic affinities

Orionothemis felixononi n. gen., n. sp. from Bahia state, Brazil, is described and illustrated from larvae, reared adults and an immature adult male taken in association with its possible larval shuck. This taxon exhibits remarkable features among the Odonata, such as enormous dorsal and lateral spines perpendicular to the body axis, totally fused last abdominal segments in the larva, strongly differentiated and sexually dimorphic posterior legs, and the incompletely chitinized eighth abdominal tergite of the adult. Orionothemis is closely related to Elasmothernis (Neotropical) and Onychothemis (South-East Asia). The larvae were collected in the abundant immersed vegetation in a clear and cool stream in the Brazilian 'planalto' (central plateau) in an area that is endangered by deforestation and irrigation. Better knowledge of the libellulid or more generally odonata larvae could help taxonomy and phylogeny of the group.