Abstract
The Petrolisthesgalathinus complex currently consists of six American species distributed in the West Atlantic, including the amphi-American P.galathinus. All species in the complex are similar in their adult morphology but differ in colour, size, larval morphology, and shape of the adult sternal plate. The West Atlantic species have different geographic ranges, which overlap in the southern Caribbean. Previously published molecular data support the monophyly of the complex, and the reciprocal monophyly of each described species and further clades corresponding to different colour morphs. Here, the morph P.caribensis "Blue" is described as Petrolisthescoeruleussp. nov., and Petrolisthesoccidentalis is formally resurrected for the Pacific individuals of P.galathinus. By adding these two species to the P.galathinus complex, this now consists of eight species. Colour illustrations of all species and colour morphs are provided and their geographic distributions and ecological ranges are discussed and updated.