Atlantic reef fish biogeography and evolution

S. R. Floeter1,2*1National Center for Ecological Analysis and Synthesis, University of California, 735 State St., 300, Santa Barbara, CA, 93101, USA2Departamento de Ecologia e Zoologia, Lab. de Biogeografia e Macroecologia Marinha, Universidade Federal de Santa Catarina, Florianópolis, SC 88010-970, Brazil*S. R. Floeter, Departamento de Ecologia e Zoologia, Lab. de Biogeografia e Macroecologia Marinha, Universidade Federal de Santa Catarina, Florianópolis, SC 88010-970, Brazil.E-mail: floeter@ccb.ufsc.br,
L. A. Rocha33Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI, 96744, USA,
D. R. Robertson44Smithsonian Tropical Research Institute, Balboa, Unit 0948, APO AA 34002, Panama,
J. C. Joyeux55Departamento de Ecologia e Recursos Naturais, Universidade Federal do Espírito Santo, Vitória, ES, 29060-900, Brazil,
W. F. Smith-Vaniz66US Geological Survey, Florida Integrated Science Center, Gainesville, FL, 32653, USA,
P. Wirtz77Centro de Ciências do Mar, Universidade do Algarve, Faro, P-8000-117, Portugal,
A. J. Edwards88School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK,
J. P. Barreiros99Departamento de Ciências Agrárias, Universidade dos Açores, 9701-851, Portugal,
C. E. L. Ferreira1010Departamento de Biologia Marinha, Universidade Federal Fluminense, Niterói, RJ, 24001-970, Brazil,
J. L. Gasparini55Departamento de Ecologia e Recursos Naturais, Universidade Federal do Espírito Santo, Vitória, ES, 29060-900, Brazil,
A. Brito1111Dpto. Biología Animal (Ciencias Marinas), Universidad de La Laguna, La Laguna, Tenerife, Islas Canarias, 38206, Spain,
J. M. Falcón1111Dpto. Biología Animal (Ciencias Marinas), Universidad de La Laguna, La Laguna, Tenerife, Islas Canarias, 38206, Spain,
B. W. Bowen33Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI, 96744, USA and
G. Bernardi1212Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
1National Center for Ecological Analysis and Synthesis, University of California, 735 State St., 300, Santa Barbara, CA, 93101, USA, 2Departamento de Ecologia e Zoologia, Lab. de Biogeografia e Macroecologia Marinha, Universidade Federal de Santa Catarina, Florianópolis, SC 88010-970, Brazil, 3Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI, 96744, USA, 4Smithsonian Tropical Research Institute, Balboa, Unit 0948, APO AA 34002, Panama, 5Departamento de Ecologia e Recursos Naturais, Universidade Federal do Espírito Santo, Vitória, ES, 29060-900, Brazil, 6US Geological Survey, Florida Integrated Science Center, Gainesville, FL, 32653, USA, 7Centro de Ciências do Mar, Universidade do Algarve, Faro, P-8000-117, Portugal, 8School of Biology, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK, 9Departamento de Ciências Agrárias, Universidade dos Açores, 9701-851, Portugal, 10Departamento de Biologia Marinha, Universidade Federal Fluminense, Niterói, RJ, 24001-970, Brazil, 11Dpto. Biología Animal (Ciencias Marinas), Universidad de La Laguna, La Laguna, Tenerife, Islas Canarias, 38206, Spain, 12Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA.

Aim To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, how they relate to each other, and what processes have contributed to faunal enrichment.
Methods 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 evaluate the operation of the main biogeographical barriers and/or filters.
Results Phylogenetic (proportion of sister species) and distributional (number of shared species) patterns are generally concordant with recognized biogeographical 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 biogeographical barriers, and (3) stochastic accretion by means of 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 lead 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.
Main conclusions Our data set indicates that both historical events (e.g. Tethys closure) and relatively recent dispersal (with or without further speciation) have had a strong influence on Atlantic tropical marine biodiversity and have contributed to the biogeographical patterns we observe today; however, examples of the latter process outnumber those of the former.

(In Journal of Biogeography)