Problems in cichlid systematics call for new characteristics to be exploited. Scale surface morphology and squamation patterns could provide novel and useful information. A comparative study comprising 105 African, 10 American, and eight outgroup species was conducted to identify the most useful scale and squamation characters within the family and to clarify their phylogenetic significance. A great number of obviously genetically fixed characters were established. At least IS scale granulation types could be identified, proving to be ofparticular value for systematic purposes. Squamation patterns on the head, breast and fins were also found to be of interest in this context. Different character states are described and their distribution is reviewed, together with a discussion of their plesiomorphic status. From the results it can be concluded that for the Cichlidae scale and squamation studies can be valuable tools in investigating phylogenetic relationships.

Scale and squamation characters have proved to be useful in investigating phyletic relationships in the family Cichlidae. To provide a sound basis for a cladistic analysis the plesiomorphic states have to be determined. This has been done for the family as a whole as well as for some phyletic lineages. Based on those characters the phylogeny within the family has been investigated. 1995 The Fisheries Society of the British Isles

Phyletic relations within the haplochromine cichlids of East Africa were investigated using scale and squamation characters. Within the L. Victoria–Edward–Kivu species flock most of the genera proposed in Greenwood's revision could be confirmed by this approach. In addition the genera could be interrelated phylogenetically. They form two distinct superlineages comprising several genera each. The genus Astatotilapia as conceived by Greenwood is diphyletic. The fluviatile members of the genus form the sister taxon of the L. Victoria–Edward–Kivu flock, while the rest are a subgroup of that flock. The flock seems to be of monophyletic origin.

Squamation and scale morphology provide interesting characters for phyletic analysis within the Cichlidae. It is not known, however, to what extent these characters are genetically fixed or determined by environmental parameters. To clarify this point, a study on Suru/herodon~u/;/ueu.~ was conducted. This species has an extensive distribution and lives in markedly different environments. Most scale characters were found to be remarkably stable within the species. The only large variations occur in scalecounts, extent ofcaudal fin squamation, number ofcirculi and radii, and the extent of scale granulation. The squamation pattcrn, the form of the circuli and radii, the shape of interradial rostrad projecting tongues, the denticles on the circuli in thc rostra1 field, and especially the kind ol'granulation in the caudal field is similar in all specimens examined and is also rctained in fish bred in aquaria for severalgenerations. Thus it seems justified to assume that these characters are strongly determined by genetic factors and that their analysis can be useful in the determination of phyletic relationships.

The Baid formation (Ad Darb locality, Tihamat Asir. SW Saudi Arabia) is Oligocene in age. The sediments have been deposited in one of a series of several alkaline continental lakes that once flanked the early Red Sea Rift. So far seven specimens of cichlid fish have been discovered there. They represent at least three different species. One species from endo-and exoskeletal characteristics can be assigned to the basal grade of cichlids, today represented mainly in Madagascar and India. The other two species seem to belong to two different clades within the African assemblage that today comprises more than 1000 species.