The distribution and geographic variation of Ninia atrata in Colombia are investigated based on 128 specimens from more than 24 localities. The Colombian specimens exhibit considerable polymorphism in color patterns. Differentiation occurs between cis-Andean and trans-Andean populations in coloration and form of the nape band and in seven of twelve morphometric characters. The variation exhibited in the Colombian populations suggest taxonomic relevance. However considering the available data limitations, the safest assertion is to consider Ninia atrata in Colombia as a single species with a high grade intraspecific variation and two distinguishable phenotypic units.
Geographic variation; Colombia; Colubridae; Ninia atrata
