Reconstructing the origin of the Indo-Malayan marine biodiversity hotspot - First glimpses from the fossil record

Reconstructing the origin of the Indo-Malayan marine biodiversity hotspot – First glimpses from the fossil record Reich, Sonja, Wesselingh, Frank P., Renema, Willem NCB Naturalis, P.O. box 9517, 2300 RA Leiden, the Netherlands sonja.reich@ncb.naturalis.nl Shallow marine biota including scleractinian corals, mangrove trees, fish, molluscs and crustaceans reach their global peak diversity in the Indo-Malayan region broadly covering Malaysia, the Philippines, Indonesia, and Papua New Guinea. The Indo-Malayan biodiversity hotspot developed in the Middle Cenozoic. In Miocene times many of the shallow marine habitats reached diversity levels similar or even exceeding those of today’s. However, the exact timing of diversification as well as the driving processes are still incompletely understood and there is only sparse fossil data to investigate diversification patterns. The THROUGHFLOW-Project, a Marie-Curie Initial Training Network, aims to fulfill the crucial need for new fossil data in the region and to investigate the history of the marine biodiversity hotspot in Indonesia. By combining a variety of palaeontological and geological projects in this multidisciplinary network we aim to document the diversification of shallow marine biota and to investigate settings and processes involved. Fossil groups under study include molluscs, bryozoans, larger and smaller benthic foraminifers, coralline algae, and corals. Fossils are collected and studied within a rigorous time-depositional framework that is initiated by stratigraphers, geochemists and sedimentologists of our team. Most of our work is carried out in East Kalimantan where a good succession of predominantly Miocene fossiliferous deposits is found. The time period includes a major regional plate tectonic reorganization at the onset of the Miocene and the Mid Miocene climate optimum. In this presentation initial insights from the 2010 and 2011 field campaigns are presented. In various places we recovered exquisitely preserved fossils of corals, molluscs, and other groups. As an example, initial insight of seagrass faunas from successive stratigraphic intervals are shown. They show the presence of high diverse communities already throughout the Early Miocene.