Late Miocene Vertebrates

The development of Eastern Alpine continental environments is closely related to the uplift of the Alps and to the changing history of the Mediterranean and the Paratethys Seas. In Austria a number of sedimentary basins subsided during the Miocene. After a last highstand in the Middle Miocene (12 million years ago) the Paratethys retreated to eastern regions. This process caused salinity changes and ultimately freshwater conditions in the Late Miocene (10 million years ago). Up to the Late Miocene the former marine ecosystems were successively replaced by terrestrial ones. New habitats for animal communities developed, including riparian forests, floodplain meadows, swamps accompanying rivers and lakes, and more open landscapes. The Late Miocene was a time of major paleogeographic reorganisations and changes in environmental and climatic conditions. This project focuses on the evolution and migrations of vertebrates 12 - 8.5 million years before present. Systematic and taxonomic investigations will be carried out on different vertebrate groups: freshwater fishes, amphibians, reptiles, small mammals and ruminants. At least 15 vertebrate faunas from the Molasse, the Vienna, the Styrian and the Pannonian Basins will be investigated. They represent different ecosystems and / or different ages. The main goals of the proposed project are: Reconstruction of the Eastern Alpine climate and of the development of aquatic and terrestrial ecosystems during the Late Miocene. Correlation of West- and Southwest versus Central versus Eastern Europe. Evaluation of biostratigraphy and correlation of continental biochronologies and the GPTS (Geomagnetic Polarity Time Scale) for the Late Miocene. Development of a data base for localities and small vertebrates from the Austrian Miocene; this data base will elaborate on the NOW data base (Neogene of the Old World). The proposed project is firmly anchored in a multidisciplinary approach, and is understood as a contribution to the Austrian FWF-Project cluster "Changes in Eastern Alpine Miocene Ecosystems and their Geodynamic Control", and as a contribution to the international project "Environments and Ecosystem Dynamics of the Eurasian Neogene (EEDEN)".

A tropical sea - brackish lake - fluvial wetlands - open landscapes: this is the Miocene metamorphosis of the Paratethys Sea and its environments in the Vienna Basin 16 - 8 million years ago. The development of Eastern Alpine continental environments is closely related to the uplift of the Alps and to the changing history of the Mediterranean and the Paratathys Seas. 12 million years ago, the Paratathys Sea successively changed from marine to brackish and freshwater conditions and finally disappeared from the Vienna Basin. A fluvial system followed the receding shore. It crossed the basin from NW towards SE and established a vast floodplain within the flat basin, whereas stagnant lakes developed along the eastern slopes of the Alps. These forested wetlands, swamps and floodplains were inhabited by species-rich vertebrate assemblages, e.g. pigs, moshids, tragulids, three-toed horses, the tapir, chalicotheres, rhinos, different proboscideans, and even apes. Among smaller mammals, climbing and gliding species dominated; they favoured mixed forests with dense bushes and included gliding squirrels, dormice and eomyids. Finally (9 million years ago), the stable warm and humid conditions changed to increasing seasonality (most probably dry/wet seasons). The forested wetland environments were partly replaced by more open landscapes (8 million years ago), as indicated by huge herds of antelopes, gazelles and three-toed horses, the first giraffes and porcupines, and the dominance of ground-dwelling mice and hamsters, which made up more than 90% of rodents (based on individual numbers). These environmental reconstructions stem from field activities in the Vienna, Molasse and Styrian Basins (2002- 2004). From 25 vertebrate faunas, almost 300 species (fishes, amphibians, reptiles, birds and mammals) were identified and fully elaborated by a team of 11 national and international co-operators. Parts of the data are presented in the WINE- and NOW-databases, others will follow soon. Furthermore, a database on SEM-images from 3000 investigated rodent teeth was compiled. Some conclusions of the project: There are many more identities in mammal species from the early Late Miocene of Austria, SW-Europe (Northern Spain) and E-Europe (Ukraine) than originally thought. Furthermore, a far- distance correlation - Central Europe versus Siberia versus Mongolia + China - hint at similar climatic and paleoenvironmental conditions between southern Siberia and Europe in the Middle Miocene, whereas there are major differences between Siberia and Mongolia + parts of China (Central Asian endemic bio-provinces).