Cover image: An anenomefish, Amphiprion perideraion, hiding in its host anemone. Patterns of reef fish diversity across the marine tropics have been shaped by barriers to dispersal, allowing regional faunas to be readily identified. By examining patterns of division through time, new research on molecular phylogenies highlights the broad temporal signal left by ‘hard’ barriers (caused by land bridges) and tighter signals of ‘soft’ barriers (caused by distance or oceanic currents). Despite their differences, hard and soft barriers both had a major effect on the evolution of coral reef fishes. See the paper by Peter F. Cowman and David R. Bellwood, published in this issue of Proceedings B (http://dx.doi.org/10.1098/rspb.2013.1541) Photo credit: Peter F Cowman, 2013.