Data from: An inverse latitudinal gradient in speciation rate for marine fishes

Far more species of organisms are found in the tropics than in temperate
and polar regions, but the evolutionary and ecological causes of this
pattern remain controversial1,2. Tropical marine fish communities are much
more diverse than cold-water fish communities found at higher
latitudes3,4, and several explanations for this latitudinal diversity
gradient propose that warm reef environments serve as evolutionary
‘hotspots’ for species formation5,6,7,8. Here we test the relationship
between latitude, species richness and speciation rate across marine
fishes. We assembled a time-calibrated phylogeny of all ray-finned fishes
(31,526 tips, of which 11,638 had genetic data) and used this framework to
describe the spatial dynamics of speciation in the marine realm. We show
that the fastest rates of speciation occur in species-poor regions outside
the tropics, and that high-latitude fish lineages form new species at much
faster rates than their tropical counterparts. High rates of speciation
occur in geographical regions that are characterized by low surface
temperatures and high endemism. Our results reject a broad class of
mechanisms under which the tropics serve as an evolutionary cradle for
marine fish diversity and raise new questions about why the coldest oceans
on Earth are present-day hotspots of species formation.