Oligo-Miocene faunal dispersal in the Indian Ocean region

At present-day, the center of maximum marine biodiversity is located in the tropical waters of the Indo-Australian Archipelago in the central Indo-Pacific. However, the origin of this marine species richness is largely unknown. Recent molecular genetic and palaeontological data indicate that the role of Pleistocene sea level changes in the formation of the biodiversity center may be less important than previously thought and that the enormous richness of underwater life has evolved through millions of years by immigration, displacement and local evolution of species controlled by the displacement of major tectonic plates and global climate fluctuations. Some modern day typical Indo-Pacific faunal elements (Tridacna giant clams, Acropora corals) originated in the area of the present Mediterranean Sea during the Eocene Epoch (~56<U+2012>34 Ma) and spread over the Indian Ocean region not until the Oligocene and Miocene (~34<U+2012>5 Ma). Due to the often incorrect taxonomic identification and unprecise age-estimates of the sparse fossil record only few information exist concerning the biogeography of the early Indian Ocean and its relationships with the Mediterranean region. In particular the Gulf of Bengal must be classed as palaeontological Terra incognita. The FWF-project Closing the gap Oligocene<U+2012>Miocene patterns of faunal dispersal and biodiversity in the Indian Ocean aims at a better understanding of the origin and changing patterns of Indo-Pacific marine biodiversity in the context of global tectonic and climatic changes. To close the knowledge gap in the NE Indian Ocean it is intended to create a modern taxonomic dataset, which includes different groups of marine organisms (gastropods, bivalves, echinoids, decapods, corals, benthic foraminifers) and offer a high level of temporal resolution (at least chronostratigraphic stages). For this purpose it is planned to sample key localities in Sri Lanka, NE India and Myanmar, which document the critical late Oligocene to middle Miocene time interval, when large-scale plate movements interrupted the marine gateways to the Mediterranean basins and the emergence of the Indo-Australian Archipelago. The integration of various palaeontological, sedimentological and stratigraphic informations will allow identifying local processes possibly overprinting the regional or global signals. The superordinate objective of the project is a comprehensive study that will integrate the palaeontological, sedimentological and stratigraphic results with comparable data sets from the central and eastern Mediterranean, Iran, Oman, western India and Tanzania, which were generated in previous FWF-projects by the working group. The high temporal and resolution and spatially precise biogeographical division intended will not only allow correlating changes in species distribution and richness to palaeoclimatic, palaeoceanographic and tectonic events in the studied late Oligocene to middle Miocene time interval but may also provide valuable information to evaluate the differential responses of recent shallow marine ecosystem in the Indo-Westpacific region to current global change.

No additional funding sources recorded.