Abstract: When discussing marine biodiversity there is a general consensus that there is a single large marine biodiversity hotspot spanning the Indo-Pacific. Known as the Indo-Australian Archipelago (IAA) biodiversity hotspot, it forms a gradient in species richness driven by the diversity found on tropical coral reefs. At its centre, this hotspot hosts over 500 species of coral and 5000 species of fish. The IAA hotspot has several characteristics that have confounded our understanding of its genesis and how this pattern is maintained across two-thirds of the world’s oceans. By examining the phylogenetic origins and biogeographic evolution of reef associated fishes, I explore the features of the IAA hotspot that I find most intriguing: i) Areas of species richness are decoupled from areas of endemism; ii) The IAA hotspot is associated with both latitudinal and longitudinal clines in species diversity; and iii) Provinces can be delineated across the Indo-Pacific gradient in the absence of definitive barriers to gene flow. By examining the roles played by processes of speciation, extinction and dispersal we can begin to understand how macroevolutionary patterns are formed on deep and shallow time scales.

Dr Peter Cowman is originally from Ireland, where he completed his undergraduate degree in Marine Science at the National University of Ireland, Galway. He received his PhD from James Cook University in 2012, where he studied the evolutionary origins of coral reef fishes. His work on the phylogenetic reconstruction of diverse reef fish families has provided a framework which has allowed him to explore patterns of origination, trophic evolution and ancestral biogeography across the global tropics. His work has highlighted the importance of coral reef association in the diversification of associated fish lineages and its potential to act as a refuge from extinction. In 2012, he joined the Macroevolution and Macroecology group at the Australian National University in Canberra as a Postdoctoral Fellow. There, he worked on the links between molecular rates of evolution, life history traits and diversification in flowering plants and fishes. In 2014, he was awarded the Donnelley Postdoctoral Fellowship by the Yale Institute for Biospheric Studies at Yale University, USA. In the Department of Ecology and Evolutionary Biology at Yale, he is currently working on reconstructing the Fish Tree of Life, molecular rate variation among basal fish lineages and the links between biodiversity, ancestral biogeography and patterns of molecular evolution.