New Polychromatic Species of Atractus (Serpentes: Dipsadidae) from the Eastern Portion of the Colombian Andes

We describe herein a new polychromatic species of the snake genus Atractus from the cloud forests of the northeastern Andes of Colombia. The new species is distinguished from all congeners by having an exclusive combination of phenotypic characters, such as: dorsal scale rows 17, loreal long, seven to ten maxillary teeth, ventrals 156-174 in females and 153-169 in males, subcaudals 20-30 in females and 23-30 in males, dorsum with variable coloration, changing from dark green to orange or red with a black nuchal band (three to four scales long) connected to a black vertebral line and two black dorsolateral continuous stripes from the occipital region to tip of the tail, venter with irregular black blotches, relatively small body size, small tail length in females and moderately long in males, hemipenis moderately bilobed, semicapitate and semicalyculate. We compared the new species with all congeners occurring along the Cordillera Oriental in Colombia, Sierra de Perija in the Colombia/Venezuela frontier and Cordillera de Merida in Venezuela. We discussed aspects related to polychromatism and its implication toward a robust taxonomy for the genus Atractus.