The Ophthalmotilapia assemblage of cichlid fishes from Lake Tanganyika, first defined by Liem (1981), originally comprised the genera Asprotilapia, Ectodus, Lestradea, Cunningtonia and Ophthalmotilapia (with which was synonymized Ophthalmochromis). The characters on which the assemblage was based are reviewed and revised in the light of information derived from large-scale outgroup comparisons.
As a result of this review, five additional genera can be included in the assemblage (viz. Aulonocranus, Grammatotria, Callochromis, Xenotilapia and Cyathopharynx (with which Cardiopharynx is synonymized). Two lineages within the Ophthalmotilapia assemblage are defined.
Previous schemes of supposed relationships for these taxa are discussed, as is the problem of identifying the sister-group for the assemblage. No sister-group can be identified amongst the endemic taxa of Lake Tanganyika, but the possibility of an endemic taxon from Lake Malawi being the sister-group is explored.
Problems arising from possible homoplasy and thus the misidentification of sister-groups
are illustrated by examples involving cichlid species from Lakes Tanganyika and Malawi,
and from these lakes and Lake Fwa (Zaire drainage basin).