Meeting Abstract
A strong latitudinal gradient in species richness characterizes diversity patterns across most terrestrial vertebrates. Spatial diversity patterns across ray-finned fishes are more poorly understood. Here we assemble the largest phylogeny of ray-finned fishes to date, comprising more than 12,000 species. We use this framework to study spatial patterns of marine ray-finned fish diversity by integrating tip data from this tree with georeferenced occurrence data. Our results reveal a strong latitudinal gradient in species richness across actinopterygians. Surprisingly, high species richness at low latitudes is not explained by differential rates of diversification. Tropical communities with high concentrations of species richness also exhibit low average rates of speciation while the most temperate communities with low richness also possess the highest rates of speciation. Clade-level analyses confirms this result: the most species rich low latitude marine lineages possess low to moderate rates of speciation while some of the highest rates of speciation across all fishes are found in high-latitude lineages. Our results are consistent with patterns reported for terrestrial birds and mammals and suggest that differential rates of origination are insufficient to explain latitudinal gradients in vertebrate species richness.
