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Keywords:

  • Biodiversity hotspot;
  • centre of origin;
  • coral reef;
  • Coral Triangle;
  • DEC model;
  • dispersal;
  • evolution;
  • Indo-Australian Archipelago;
  • Lagrange ;
  • survival

Abstract

Aim

To use recently published phylogenies of three major reef fish families to explore global patterns of species origin and dispersal over the past 65 million years. The key questions are: when and where did reef fishes arise, and how has this shaped current biodiversity patterns?

Location

Biogeographic reconstructions were performed on globally distributed reef fish lineages. Patterns of lineage origination and dispersal were explored in five major biogeographic regions: the East Pacific, the Atlantic, the Indian Ocean, the Indo-Australian Archipelago hotspot, and the Central Pacific.

Methods

A dispersal, extinction and cladogenesis (DEC) model implemented in Lagrange was used to infer the most likely biogeographic scenarios at nodes on chronograms of three diverse reef fish families (Labridae, Pomacentridae, Chaetodontidae). For the terminal branches ANOVA was used to compare patterns of origination on a regional and global scale. Patterns of origination and dispersal were examined within discrete time periods for the five biogeographic regions.

Results

Temporal examination of hypothetical ancestral lineages reveal a pattern of increasing isolation of the East Pacific and Atlantic regions from the Eocene, and the changing role of the Indo-Australian Archipelago from a location of accumulating ranges in the Palaeo/Eocene, a centre of origination in the Miocene, to extensive expansion of lineages into adjacent regions from the Pliocene to Recent.

Main conclusions

While the East Pacific and Atlantic have a history of isolation, the Indo-Australian Archipelago has a history of connectivity. It has sequentially and then simultaneously acted as a centre of accumulation (Palaeocene/Eocene onwards), survival (Eocene/Oligocene onwards), origin (Miocene onwards), and export (Pliocene/Recent) for reef fishes. The model suggests that it was the proliferation and expansion of lineages in the Indo-Australian Archipelago (the Coral Triangle) during the Miocene that underpinned the current biodiversity in the Indian and Pacific Oceans.