The cat-eyed snakes of the genus Madagascarophis are among the most commonly encountered snake species in Madagascar. Yet despite their broad distribution and frequent occurrence in human-disturbed habitat, Madagascarophis still contains unrecognized species diversity. Here, we describe a new species of Malagasy cat-eyed snake from a specimen found in the tsingy karst system of Ankarana in northern Madagascar. Using multiple loci from all currently described species, including the never-before-sequenced M. ocellatus, we delimit a new species and also determine its placement within the genus in a Bayesian coalescent framework, using BPP and *BEAST, respectively. Our results indicate that molecular data are sufficient to delimit this new taxon. These data also support its placement as the sister taxon to the recently described M. fuchsi which is endemic to the Montagne des Français karst massif also in northern Madagascar. We also provide a morphological description of this new snake species, which can be readily diagnosed based on external morphological characters, and include a species identification key for the entire genus based on external morphology.