A new species of spider crab, Pyromaia acanthina, is described based on specimens collected during a recent sampling program along the Caribbean coast of Colombia. This new species is most similar to P. propinqua Chace, 1940, a species also collected during this study that had not been found or mentioned in the literature since its original description from Cuba. The presence of these two species on the Colombian coast represents the first record of the genus Pyromaia Stimpson, 1871 in the southern Caribbean or northeastern South America. Pyromaia propinqua is redescribed and compared with the new species. The two differ from the other congeners, P. cuspidata Stimpson, 1871, P. arachna Rathbun, 1924, and P. tuberculata (Lockington, 1877), in features of the carapace, ambulatory legs, and male first pleopods. A summary of the classification of this genus, its definition, and distribution of species is presented together with a key to their identification.