In 2001, Allgayer described a cichlid from the Rio Cañaveral (Rio Caña), Panama (Province Bocas del Toro), as Cryptoheros altoflavus (also known as A. sp. 'caña' up to then). A. altoflavus is closely related to A. nanoluteus from the Rio Guaramo basin in Panama (Province Boca del Toro). A. altoflavus can be differentiated from A. nanoluteus by its higher body, its longer head and the reduction of the black color pattern (Allgayer, 2001).
According to Christian & Xafer Hofer (personal communication), the elaboration of black pigmentation can vary tremendously within the same population, ranging from present as in A. nanoluteus to almost absent as in A. altoflavus. As known from other fish species, the body proportions (as body height) can vary among populations depending on environmental factors. Variation in black coloration as well as body proportions within and among populations can also be observed in A. nigrofasciatus (personal observation in several Costa Rican populations) and other Central American cichlids. Thus, fish designated as A. altoflavus might in fact be a geographical (ecological?) variant of A. nanoluteus rather then a separate species. Further investigations thus have to investigate within and among populations variation of this form. Such data can provide additional information if A. altoflavus is a separate species or a junior synonym of A. nanoluteus.
Archocentrus altoflavus male from Rio Caña, Pánama, in the aquarium of Jacques Blanc; Manesque, France. Note especially the reduced black color pattern compared to Archocentrus nanoluteus. Photo by Jacques Blanc.