The closely related Ctenopoma petherici and C. kingsleyae are allopatrically distributed over much of central and west Africa. Ctenopoma petherici is limited largely to nonforested habitats throughout the Nilo-Sudanic region, whereas C. kingsleyae occurs in forested regions of Zaire and upper and lower Guinea. Variability within and between species has long confused the taxonomic status of these two forms, and, in fact, synonymy has been argued for in the literature. In this study, we document geographic variation for both species by plotting in three-dimensional space population scores derived from regular and sheared principal component analyses of morphometric and meristic characters. We then distinguish 204 C. kingsleyae from 172 C. petherici with 95% accuracy, based upon three (or six) meristic characters entered into a stepwise multiple discriminant analysis. A similar evaluation, based upon nine (of 33) morphometric characters from 67 C. petherici and 70 C. kingsleyae, correctly classified 84.7% of the fish. We, thus, conclude that the two species are indeed separate entities; they can be clearly allocated to species on the basis of three key meristic counts and a classification function provided herein. A diagnosis and description of each species is furnished. The biogeographic significance of the distribution of these fishes is discussed. In addition, Anabas breviventralis is placed in synonymy with C. kingsleyae, whereas A. riggenbachi and A. togoensis are both placed in synonymy with C. petherici.
