Title: ORIGIN AND MAINTENANCE OF REEF FISH BIODIVERSITY IN SEAMOUNTS AND OCEANIC ISLANDS OF THE SOUTH ATLANTIC

Abstract: In the Southwestern Atlantic, twelve species are considered endemic to the seamounts and islands of the Vitória-Trindade Chain (VTC). Endemic species exclusive to the islands are suggested to have undergone allopatric speciation after sea level made the seamounts connecting continental and insular populations uninhabitable by shallow water species. These island endemic species are small and have limited dispersal ability. Most of them are genetically and morphologically very similar to their mainland sister species, suggesting recent divergence. Others endemics are wide spread along deeper (mesophotic) ecosystems of VTC seamounts and islands, and also show evidence of recent divergence. However, simple isolation cannot explain the origins of these species. In addition, two species endemic to the shallow waters of the islands and two from mesophotic habitats along the chain are much older than most species (i.e.: paleo-endemics or relict species). We hypothesize that VTC seamounts became a refugia for coral reef fauna during Pleistocene climatic variations, preserving these relict lineages, probably due to environmental stability. Therefore, VTC islands and seamounts seem to be acting as both cradle and museums for reef fish biodiversity.

Authors: Pinheiro HT, Bernardi G, Simon T, Joyeux JC, Rocha LA

Presentation: Oral

Session: 28A

Date: 06/20/16

Time: 14:45

Location: 308 A/B

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