Aphyosemion cauveti, a new species, belongs to the subgenus Scriptaphyosemion. This species is distinguished from its closer geographical relatives by a vivid red pigmentation on the flanks and the lowest number of chromosomes (2n = 36) among the representatives of Scriptaphyosemion. From present observations, A. cauveti shows a restricted distribution in a tributary of the Kolenté River near the town of Kindia in Guinea. A phylogenetic analysis shows the relationships between subgenera of Aphyosemion west of Ghana where the Callopanchax subgenera is the most primitive one from which others have derived.