title: Genetic and morphological population differentiation in the rock-dwelling and specialized shrimp-feeding cichlid fish speciesAltolamprologus compressicepsfrom Lake Tanganyika, East Africa.
abstract: With about 250 endemic species, Lake Tanganyika contains an extraordinarily diverse cichlid fish fauna, and thus represents an ideal model system for the study of pathways and processes of speciation. The Lamprologini form the most species-rich tribe in Lake Tanganyika comprising about 100 species in seven genera, most of which are endemic to the lake. They are territorial substrate-breeders and represent a monophyletic tribe. By combined analysis of population genetics and geometric morphometric markers, we assessed gene flow among three populations of the highly specialized shrimp-feeding rock-dwellerAltolamprologus compressiceps, separated by geographic distance and ecological barriers. Five highly polymorphic microsatellite markers were analyzed in conjunction with 17 landmarks in order to compare genetic differences to body shape differences among populations. Both genetic and morphological analyses revealed significant differentiation among the three studied populations. A significant, but overall relatively low degree of genetic differentiation supports a very recent divergence. Phenotypic differentiation was primarily found in the head region ofA. compressiceps. In agreement with findings in other cichlid species, similar adaptations to specialized feeding mechanisms can consequently lead to marginal shape changes in the trophic apparatus.
authors.affiliation: Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria ; Department of Biology, University of Konstanz, Universitätsstraße 10, 78457 Constance, Germany.
authors.forename: Maria Luise
authors.initials: ML
authors.lastname: Spreitzer
authors.affiliation: Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: Selma
authors.initials: S
authors.lastname: Mautner
authors.affiliation: Department of Fisheries, Mpulungu, Zambia.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Makasa
authors.affiliation: Department of Zoology, University of Graz, Universitätsplatz 2, 8010 Graz, Austria.
authors.forename: Christian
authors.initials: C
authors.lastname: Sturmbauer
keywords: Geometric morphometrics; Lamprologini; Microsatellites; Population differentiation; Speciation; Zambia