Oral Presentation Australian Society for Fish Biology Conference 2017

The biogeography of tropical reef fishes: endemism and provinciality through time (#99)

Peter Cowman 1 , Valeriano Parravicini 2 , Michel Kulbicki 3 , Sergio Floeter 4
  1. James Cook University, Townsville, QLD, Australia
  2. Ecole Pratique des Hautes Etudes, University of Perpignan, France
  3. Institut de Recherche pour le developpement (IRD), Laboratoire Arago,, Banyuls/mer, France
  4. Marine Macroecology and Biogeography Lab., Departamento de Ecologia e Zoologia, Universidade Federal de Santa Catarina, Florianopolis, Brazil

The largest marine biodiversity hotspot straddles the Indian and Pacific Oceans, driven by taxa associated with tropical coral reefs. Centred on the Indo-Australian Archipelago (IAA), this biodiversity hotspot forms the ‘bullseye’ of a steep gradient in species richness from this centre to the periphery of the vast Indo-Pacific region. Complex patterns of endemism, wide-ranging species and assemblage differences have obscured our understanding of the genesis of this biodiversity pattern and its maintenance across two-thirds of the world’s oceans. But time-calibrated molecular phylogenies coupled with ancestral biogeographic estimates have provided a valuable framework in which to examine the origins of coral reef fish biodiversity across the tropics. Herein, we examine phylogenetic and biogeographic data for coral reef fishes to highlight temporal patterns of marine endemism and tropical provinciality. The ages and distribution of endemic lineages have often been used to identify areas of species creation and demise in the marine tropics and discriminate among multiple hypotheses regarding the origins of biodiversity in the IAA. Despite a general under-sampling of endemic fishes in phylogenetic studies, the majority of locations today contain a mixture of potential paleo- and neo-endemic fishes, pointing to multiple historical processes involved in the origin and maintenance of the IAA biodiversity hotspot. Increased precision and sampling of geographic ranges for reef fishes has permitted the division of discrete realms, regions and provinces across the tropics. Yet, such metrics are only beginning to integrate phylogenetic relatedness and ancestral biogeography. Phylogenetic dissimilarity clustering of extant assemblages identifies a large Indo-West Pacific cluster, but also clusters distant Pacific island together based on peripherally isolated, but phylogenetically close lineages. Through time, clustering of estimated ranges reveals the dynamic nature of reef assemblages with provincial changes reflecting large scale tectonic rearrangement of the tropical belt.