Data from: Unravelling the roles of recent speciation and trait evolution in shaping the longitudinal gradient of tropical reef fish diversity

Aim In the tropical marine realm, the increasing concentration of species
toward the Indo-Australian Archipelago (IAA) has been extensively studied.
The literature provides numerous biogeographical scenarios explaining this
pronounced longitudinal diversity gradient. However, most proposed
scenarios did not consider the interplay between recent speciation and
trait evolution, nor the influence of diversity-dependent processes.
Location Global and regional. Taxon  Tropical reef fishes Methods
Based on a global data set on tropical reef fish distributions, combined
with species traits (body size, trophic level and maximum depth range) and
a comprehensive Actinopterygii phylogeny, we estimated assemblage-level
speciation rates across the world’s tropical marine ecoregions, as well as
assemblage-level trait evolution rates. We then apply a causal modelling
approach that simultaneously accounts for the potential influence of both
current and past environmental conditions on rates of recent speciation
and trait evolution, and ultimately, on species richness distribution.
Results  Our results reveal gradients in speciation rates and
trait evolution rates that do not match the spatial distribution of
species richness. Compared to other regions, the species-rich IAA did not
exhibit higher rates of either recent speciation or trait evolution. In
contrast,  the Caribbean region exhibited the greatest rates of
recent speciation, but this pattern was uniquely driven by the recent
radiation of hamlets (Hypoplectrus spp). Caribbean and Southwestern
Atlantic reefs were also shown to harbor species with faster recent
evolution in body size and maximum depth. Finally, regardless of the
biogeographic realm considered (Indo-Pacific, Atlantic, or Tropical
Eastern Pacific), species richness was found to strongly constrain trait
evolutionary rates related to trophic level. Main conclusions Overall, our
findings suggest that the longitudinal gradient in tropical reef fish
diversity is unrelated to either recent speciation or recent trait
evolution, and that the IAA no longer functions as a center of origination
for tropical reef fishes. Our results also suggest that
diversity-dependent mechanisms may have played a key role in shaping
biogeographic patterns of recent evolution of trophic level in tropical
reef fishes.