A new genus of Oonopidae, Puan, is described from Argentina. The genus exhibits several features also found in orsolobids, including a well-sclerotized sperm duct and an H-shaped eye pattern. Puan resembles the oonopid genus Unicorn Platnick and Brescovit but differs in male palpal morphology. In addition, males lack the clypeal horn characteristic of Unicorn. Two new species, P. chechehet and P. nair, are described from the southwestern mountains of Buenos Aires province. Complex copulatory bulbs are the principal characteristic of these species and could be a synapomorphy for the genus.