ABSTRACT

The aim was to understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, what processes
have contributed to faunal enrichment, and how they relate to each other. The distributions of 2605 species of reef fishes were compiled
for 25 areas of the Atlantic and southern Africa. Maximum parsimony and distance analyses were employed to investigate biogeographical
relationships among those areas. A collection of 26 phylogenies of various Atlantic reef fish taxa was used to assess patterns of origin and
diversification relative to evolutionary scenarios based on spatio-temporal sequences of species splitting produced by geological and
palaeoceanographic events. We present data on faunal (species and genera) richness, endemism patterns, diversity buildup (i.e.
speciation processes), and discuss the operation of the main biogeographic barriers and/or filters. The phylogenetic (proportion of sister
species) and distributional patterns (number of shared species) are generally concordant with recognized biogeographic provinces in the
Atlantic. The highly uneven distribution of species in certain genera appears to be related to their origin, with highest species richness in
areas with the greatest phylogenetic depth. Diversity buildup in Atlantic reef fishes involved (1) diversification within each province, (2)
isolation as a result of biogeographic barriers, and (3) stochastic accretion via dispersal between provinces. The timing of divergence
events is not concordant among taxonomic groups. The three soft (non-terrestrial) inter-regional barriers (mid-Atlantic, Amazon, and
Benguela) clearly act as “filters” by restricting dispersal but at the same time allowing occasional crossings that apparently leads to the
establishment of new populations and species. Fluctuations in the effectiveness of the filters, combined with ecological differences
among provinces, apparently provide a mechanism for much of the recent diversification of reef fishes in the Atlantic. Our dataset indicates
that both historical events (e.g. Tethys closure) as well as relatively recent dispersal (with or without further speciation) have had a strong
influence on Atlantic tropical marine biodiversity and have contributed to the biogeographic patterns we observe today, however, examples
of the latter process outnumber the former.

Luiz, O. J., Madin, J. S., Robertson, D. R., Rocha, L. A., Wirtz, P. & Floeter, S. R. 2012. Ecological traits influencing range expansion across
large oceanic dispersal barriers: insights from tropical Atlantic reef fishes. Proceedings of the Royal Society of London, 279: 1033–1040. 
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Floeter, S. R., Rocha, L. A., Robertson, D. R., Joyeux, J. C., Smith-Vaniz, W. F., Wirtz, P., Edwards, A. J., Barreiros, J. P., Ferreira, C. E. L., 
Gasparini, J. L., Brito, A., Falcón, J. M., Bowen, B. W. & Bernardi, G. 2008. Atlantic reef fish biogeography and evolution. Journal of 
Biogeography, 35: 22–47. {PDF}