A new semifossorial snake of the genus Arrhyton (Squamata: Dipsadidae) from eastern Cuba, with taxonomic comments on other species.

The genus Arrhyton is endemic to Cuba, with eight currently known species. A new species, Arrhyton albicollum sp. nov., is described from the karst areas of Gibara, Holgun Province. The new species is closely related to A. redimitum, another eastern species, according to morphology and molecular phylogeny. It differs from all other species of the genus by having a conspicuous, white nuchal band, a contrasting black pattern on the head, a gray-colored body with faint stripes, and a high number of ventral and subcaudal scales. Additional comments on other species include new locality records and information on morphology and relationships.