Figure 1.
Map of collection sites for Brachyrhaphis terrabensis, B. roseni, and B. rhabdophora used in this study.
Brachyrhaphis terrabensis (open circles) occur at higher elevations in streams that are void of fish predators. Brachyrhaphis roseni (closed circles) occur at lower elevations in streams that have abundant predators. Brachyrhaphis rhabdophora occur at sites that are both predator (closed squares) and predation free (open squares).
Figure 2.
Least Square Means of Relative Warps.
Graph of least square means of relative warp (RW) scores (±SE) for Brachyrhaphis roseni (•), B. terrabensis (▾), B. rhabdophora from predator environments (▪), and B. rhabdophora from predator free environments (▴). Filled symbols represent males, and open symbols represent females. Female body shape converges relative to male body shape in B. roseni, B. terrabensis and populations of B. rhabdophora from divergent predation environments.
Table 1.
Results of mixed-repeated-measures MANOVA testing for interactions between combinations of species-group, predation-environment, size and index-variable.
Table 2.
Results of mixed-repeated-measures MANOVA examining shape variation and sexual dimorphism in Brachyrhaphis.
Table 3.
Statistical assessment of differences in trajectory size/ direction among trajectories characterizing sexual dimorphism in Brachyrhaphis.
Figure 3.
Morphological Divergence in Female Brachyrhaphis.
Visualization of morphological divergence with centroid size in female Brachyrhaphis roseni (a), B. terrabensis (b), and B. rhabdophora from predator (c) and predator free (d) environments. Thin-plate spline transformations depict the end points of the centroid size axis (i.e. the smallest and largest individuals). Shaded regions are drawn to aid in interpretation. Note the increase in abdomen distension and decrease in caudle peduncle region in large females. Deformations are scaled to 3X to assist interpretation of the shape differences.
Figure 4.
Morphological Divergence in Male Brachyrhaphis.
Visualization of morphological divergence with centroid size in male Brachyrhaphis roseni (a), B. terrabensis (b), and B. rhabdophora from predator (c) and predator free (d) environments. Thin-plate spline transformations depict the end points of the centroid size axis (i.e. the smallest and largest individuals). Shaded regions are drawn to aid in interpretation. Note the shortening and deepening of the head region and the reduction in the caudle peduncle region in large males. Deformations are scaled to 3X to assist interpretation of the shape differences.