Abstract
We present the first description of female adult and larva of Phyllocycla basidenta Dunkle 1987 (Anisoptera: Gomphidae), collected in northwestern Argentina. The female and larva are described in detail, with diagnostic features that differentiate P. basidenta from other species like P. argentina and P. viridipleuris. Larvae of P. basidenta inhabit sandy-bottomed rivers alongside P. argentina. Additionally, we predict the potential distribution of both species using Ecological Niche Models under current and future climate scenarios. The models suggest that suitable habitats may shift to higher altitudes under moderate climate change, but significant losses are expected under severe warming scenarios. Climate change may threaten Phyllocycla basidenta and P. argentina as its suitable habitats could shift to higher elevations. Conservation strategies should prioritize areas projected to become suitable under future conditions.