Terrestrial vertebrates from the Sarmatian (late Serravallian) of the Central Paratethys – the fossil site of Gratkorn (Styrian Basin, Austria)

Abstract

The Paratethys Sea represents a huge landlocked water body of western Eurasia, which evolved during the Cenozoic era from open to restricted marine conditions towards brackish and lacustrine basins (Rogl and Steininger 1983). Due to the endemic evolution of Paratethyan biota and the tectonics of the Alpine orogeny, chronostratigraphic correlations and basin evolution are still partly a matter of debate and a subject of intense scientific research. Despite the mainly marine or lacustrine sedimentation (Steininger et al. 1985), fossils of continental biota are not rare in deposits in the Paratethyan realm. Notably, terrestrial vertebrates have been known for a long time (e.g. Eichwald 1835), but well-documented excavations and faunas are rare or absent from many stratigraphic stages and basins. This is especially true for the Sarmatian regional stage when the Paratethys was becoming isolated from the world oceans (Piller et al. 2007). This chronostratigraphic stage is crucial, because the Sarmatian sensu stricto (=Volhynian and early Bessarabian) represents the last period with a uniform marine biofacies in the entire Paratethys, extending from the Styrian Basin in the west to the Lake Aral in the east (Steininger and Wessely 2000). While the deposits cover a huge area, terrestrial biota are still a rarity, and those from the early to late Sarmatian transition (Volhynian–Bessarabian transition) virtually unknown. The discovery of the Gratkorn fossil site due to geologic mapping in 2005 gives a unique opportunity to study continental ecosystems of this specific time horizon (12.2– 12.0 Ma, early to late Sarmatian transition). Systematic palaeontologic excavations starting in 2006 have been carried out in a cooperation between the Universalmuseum Joanneum (Graz), the Ludwig Maximillians Universitat Munchen, and the Eberhard Karls Universitat Tubingen. Besides abundant fossils of plants (leafand carpoflora), molluscs (gastropods and mussels), and arthropods (insects, ostracodes, and crabs), more than 1,500 specimens of vertebrates have so far been excavated. These fossils cover all major groups of vertebrates, namely fishes, amphibians, reptiles, birds, and mammals, rendering Gratkorn a benchmark locality for continental biota from the Sarmatian of the Central Paratethys. This special issue is dedicated to Prof. Dr. Friedrich Franz Steininger on the occasion of his 75th birthday in 2014, and in honour of his noteworthy scientific contributions to chronostratigraphy, palaeogeography, and biofacies of the Paratethys Sea. Twelve publications have been brought together summarising the first nearly 10 years of research at Gratkorn. They deal with the geology of the Gratkorn locality, the vertebrate taphonomy, and selected aspects of vertebrate taxonomy and ecology. Further scientific contributions to Gratkorn, e.g. the macro-flora and the carnivore mammals, are in preparation and will shortly be published in a forthcoming issue of Palaeobiodiversity and Palaeoenvironments. This article is a contribution to the special issue “The Sarmatian vertebrate locality Gratkorn, Styrian Basin.”