Figure 1.
Study area and model organism.
(a) Location of the study area in Africa. (b) Map of the study area illustrating the spatial hierarchical structure of the habitat: location of different inselbergs housing pool clusters with fairy shrimp populations in the regional landscape (right), location of different pool clusters on a single inselberg (Korannaberg North) (top left) and different populations embedded in one pool cluster (cluster A, Korannaberg North) (bottom left). (c) Typical rock pool located at the summit of the inselberg Taba Phatshwa, Free State, South Africa (Photo courtesy of Bram Vanschoenwinkel), (d) Branchipodopsis fairy shrimp (Photo courtesy of Dirk Ercken); right: B. cf. wolfi male, middle: B. drakensbergensis male, left: B. sp. female. inset: scanning electron microscopic picture of a B. sp. dormant egg (230 µm diameter). Females and dormant eggs of both species cannot be distinguished morphologically.
Table 1.
Overview of sample locations.
Table 2.
Distribution of COI mtDNA haplotype for B. drakensbergensis and B. cf. wolfi among different pools, pool clusters and inselbergs.
Figure 2.
Statistical parsimony networks showing the evolutionary relations and geographic occurrence of (a) Branchipodopsis cf. wolfi and (b) Branchipodopsis drakensbergensis mitochondrial haplotypes numbered according to Table 1. Pie charts illustrate distribution and relative abundance of each haplotype on different inselbergs. Size of circles is proportional to the number of individuals included (bottom right). Perpendicular black dashes represent hypothetical intermediate haplotypes. The numbers of such dashes between two haplotypes indicates the number of mutational steps involved.
Figure 3.
Haplotype distributions indicating long distance dispersal events.
Geographic distribution of haplotypes of (a) Branchipodopsis cf. wolfi and (b) Branchipodopsis drakensbergensis among inselbergs (right), among the different pool clusters on Korannaberg North (top left) and among different pools within pool cluster A on Korannaberg North (bottom left). Pie charts depict relative abundance of haplotypes at each site. The proportion of haplotypes unique to a certain locality is highlighted in orange. A Ø symbol indicates that the respective species was not found at this locality. Arrows indicate long distance dispersal events detected in our analyses. Dashed arrows mark initial colonization events based on the topology of the haplotype network, colored arrows illustrate more recent migration evidenced by haplotype sharing. Direction of dispersal could not be determined for haplotypes 5, thus no arrow was plotted.