The evolution of latitudinal range limits in tropical reef fishes: heritability, limits, and inverse Rapoport's rule

Aim In this study we explore patterns and evolutionary processes of tropical reef fish latitudinal ranges, namely the degree of similarity in range size between ancestor and descendant lineages (i.e. phylogenetic signal); the evolution of range limits; and the latitudinal distribution of range sizes, particularly with respect to Rapoport9s rule. Location Global. Taxon Tropical reef fishes. Methods We integrate data on the latitudinal distribution and evolutionary history of 5,071 tropical reef fish species with phylogenetic comparative methods to assess the level of phylogenetic signal in latitudinal range size, low- and high-latitude limits, and range medians, and to estimate rates of evolution of those traits. Finally, we test whether latitudinal ranges become smaller near the equator, as predicted by Rapoport9s rule, using phylogenetic generalized least squares. Results There were varying levels of phylogenetic signal in latitudinal range size, low- and high-latitude limits, and range medians. Despite these differences, latitudinal medians were consistently shown to have the highest phylogenetic signal among all measured geographic features. Interestingly, the position of high-latitude limits in general evolved at substantially faster rates than their low-latitude counterparts. Finally, we confirm for the first time the existence of an inverse Rapoport9s rule in marine fishes using phylogenetic comparative methods. Main conclusions We uncovered several congruent patterns in latitudinal ranges of tropical reef fish, despite vastly disparate biogeographical distributions and ecological differences between the studied fish lineages. Such broad congruence suggests that the evolution of latitudinal ranges of reef fishes may be governed by common principles.