Data from: Body shape convergence driven by small size optimum in marine angelfishes

Convergent evolution of small body size occurs across many vertebrate
clades and may reflect an evolutionary response to shared selective
pressures. However it remains unclear if other aspects of phenotype
undergo convergent evolution in miniaturized lineages. Here we present a
comparative analysis of body size and shape evolution in marine
angelfishes (Pomacanthidae), a reef fish family characterized by repeated
transitions to small body size. We ask if lineages that evolve small sizes
show convergent evolution in body shape. Our results reveal that angelfish
lineages evolved three different stable size optima with one corresponding
to the group of pygmy angelfishes (Centropyge). Then, we test if the
observed shifts in body size are associated with changes to new adaptive
peaks in shape. Our data suggest that independent evolution to small size
optima have induced repeated convergence upon deeper body and steeper head
profile in Centropyge. These traits may favour manoeuvrability and visual
awareness in these cryptic species living among corals, illustrating that
functional demands on small size may be related to habitat specialization
and predator avoidance. The absence of shape convergence in large marine
angelfishes also suggests that more severe requirements exist for small
than for large size optima.