Systematics of Snakes Referred to Dipsas variegata in Panama and Western South America, with Revalidation of Two Species and Notes on Defensive Behaviors in the Dipsadini (Colubridae)

Abstract

Abstract The name Dipsas variegata (Dumeril, Bibron, and Dumeril) has been applied to snakes disjunctively distributed in northeastern South America and in Panama and western South America. The specific name variegata is here restricted to populations occurring from Venezuela to Trinidad and French Guiana, and seemingly to the mouth of the Amazon in Brazil. Records from Colombia are unsubstantiated. The name Dipsas nicholsi (Dunn) is revalidated for a Central American endemic with an exceptionally small range in central Panama. Specimens from western Ecuador previously assigned to “Dipsas variegata nicholsi” represent a different species—Dipsas andiana (Boulenger), which is resurrected from the synonymy of Dipsas oreas (Cope). Other records of Dipsas variegata from western Ecuador and southeastern Peru are based on misidentifications of species well known from those areas. Dipsas nicholsi and D. andiana differ in some scutellation, hemipenial, and color pattern characters. The two species share an unusual...