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Additional file 1: This additional file contains supplementary information to the main text and consists of supplementary text, table S1, figure S1 and S2. Supplementary text includes additional methodological descriptions and results. The additional methodological descriptions contain a description of sampling procedures, technical information on how aquaria were set up, extended experimental procedures that were required by ampullariid biology, information for reproducibility of morphometric data collecting, and descriptions of the models that were used in model-based clustering. Additional results consist of direct observations on the reproduction of Lanistes. Table S1. Results of E-tests of multivariate normality per morphospecies and generation. Figure S1. Comparison of the morphospace occupation reconstructed by non-metric multidimensional scaling (nmMDS) in 2 and 3 dimensions along nmMDS1 and 2, with vectors representing how individual specimens are displaced from the 3D configuration to the 2D configuration. Figure S2. Geometric morphometric shape changes along nmMDS1 and 2.

List of taxa and GenBank [51] accession numbers for sequences of COI, 16S and 18S used in phylogenetic analysis [6, 52â 55]. (DOCX 20 kb)

Phylogenetic tree of ampullariids based on DNA sequences of cytochrome c oxidase I (COI), 16S rRNA (16S) and 18S rRNA (18S) as listed in Additional file 2. Sequences were aligned and gaps were trimmed with MUSCLE. Phylogenetic analysis was conducted using the concatenated sequences (COI: 502 bp; 16S: 362 bp; 18S: 269 bp). The maximum-likelihood method implemented in MEGA5 [50] was used and the GTR + Γ + I evolutionary model was selected. Members of Viviparidae and Campanilidae served as outgroups. Values at nodes are percentages of 100 bootstrap replicates. Scale bar represents 0.1 substitution per site. Species with transcriptomes assembled in the present study are highlighted in blue. List of taxa and GenBank accession numbers for sequences of COI, 16S and 18S used in phylogenetic analysis. (DOCX 364 kb)

This supplement contains additional sampling information, technical protocols, an examination of habitats, 5 data tables and 10 additional figures.

BACKGROUND: The formation of the East African Rift System has decisively influenced the distribution and evolution of tropical Africa´s biota by altering climate conditions, by creating basins for large long-lived lakes, and by affecting the catchment and drainage directions of river systems. However, it remains unclear how rifting affected the biogeographical patterns of freshwater biota through time on a continental scale, which is further complicated by the scarcity of molecular data from the largest African river system, the Congo. RESULTS: We study these biogeographical patterns using a fossil-calibrated multi-locus phylogeny of the gastropod family Viviparidae. This group allows reconstructing drainage patterns exceptionally well because it disperses very poorly in the absence of existing freshwater connections. Our phylogeny covers localities from major drainage basins of tropical Africa and reveals highly disjunct sister-group relationships between (a) the endemic viviparids of Lake Malawi and populations from the Middle Congo as well as between (b) the Victoria region and the Okavango/Upper Zambezi area. CONCLUSIONS: The current study testifies to repeated disruptions of the distribution of the Viviparidae during the formation of the East African Rift System, and to a central role of the Congo River system for the distribution of the continent´s freshwater fauna during the late Cenozoic. By integrating our results with previous findings on palaeohydrographical connections, we provide a spatially and temporarily explicit model of historical freshwater biogeography in tropical Africa. Finally, we review similarities and differences in patterns of vertebrate and invertebrate dispersal. Amongst others we argue that the closest relatives of present day viviparids in Lake Malawi are living in the Middle Congo River, thus shedding new light on the origin of the endemic fauna of this rift lake.