On the basis of new characters, I reevaluated species groups of Dipsas. A new species described from the Serranía de la Macarena, Colombia, resembles species of the D. articulata and D. pratti groups. I redescribe D. temporalis based on new material and identify apomorphic characters shared between D. temporalis, D. pakaraima, and D. vermiculata. Dipsas incerta is a species distinct from D. copei, although it may be a synonym of another species, most likely D. praeornata. Neotypes recently designated for D. incerta and D. alternans violate qualifying conditions of article 75 of the International Code of Zoological Nomenclature and are invalid. Characters of visceral morphology improve our understanding of dipsadine relationships. Within Dipsas, I recognize eight species groups and propose a new key to the South American species.