Meeting Abstract
Herbivorous fishes play a key role in coral reef habitats, controlling the growth of algae on corals and thereby preventing negative cascading effects on both reef health and community-wide patterns of species diversity. Herbivory has evolved independently in several groups of coral reef fishes, including rabbitfishes (Siganidae) and surgeonfishes (Acanthuridae). Although both of these groups posses a rich fossil record that makes them ideal groups from which to study how the evolution of herbivory has impacted reef fish diversification dynamics, few studies have investigated these clades in detail. Combining molecular and morphological datasets that include both extant and fossil taxa into a total evidence approach, we provide a new timescale for the evolutionary history of these clades. Our results demonstrate much earlier origins of these groups than those indicated by the fossil record, supporting a substantial a radiation of herbivorous fishes that began in the Cretaceous, followed by episodes of significant extinction during the late Eocene and Oligocene. Integrating our timetree with morphometric data collected from over 1000 digitized images for both groups, we further investigate the tempo and mode of phenotypic evolution within these clades, and will discuss our findings.
