An Introduction to the Taxonomy and Morphology of the Haplochromine Cichlidae from Lake Victoria

Abstract

The haplochromine Cichlidae endemic to Lake Victoria are recently estimated to comprise approximately 200 species. Morphologically these species vary within narrow limits but ecologically they demonstrate a wide and continuous spectrum of adaptations. Except for the papyrus swamps, the fish-fauna of each habitat is dominated by a particular community of haplochromine species. Besides restrictions to certain habitats most species have limited food-regimes. Together these diets comprise all food categories available (possibly with exception of zooplankton). Morphologically similar species realizing such a wide scala of adaptations are ideal objects for comparative biological research. For this reason haplochromine cichlids have been recently introduced into ethology, ontogeny, physiology, functional morphology and-naturally-ecology. Another recent interest in these fishes concerns their potential economic importance: the overwhelming quantity with which haplochromine cichlids (still) occur, together with an improved fishing gear, make these relatively small fishes a source for fishmeal and human consumption. Regrettably no ecological survey preceded the planning for these extensive fisheries. A major cause for this omission are the difficulties experienced in identifying haplochromine species. These difficulties result partly from the overall morphological similarity and partly from the fact that only half the estimated number of species has been described so far. The importance of identification for both fishery-biology, ecology and other biological research has been the main reason for writing this paper which introduces the techniques applied in the taxonomy of the haplochromine Cichlidae from Lake Victoria. As this taxonomy is mainly based on morphological characters, the paper consequently provides basic information on the anatomy and external aspects of these cichlids. The subtitle refers to the fact that all currently valid species have been described (or revised) by GREENWOOD in a long series of papers mainly intended for the use of taxonomists. The present introduction has been explicitly written for students unfamiliar with the morphology and taxonomy of haplochromine fishes. After a short review of the problems related to haplochromine taxonomy, there