Tiger shark feeding on sirenian - first fossil evidence from the middle Miocene of the Styrian Basin (Austria)

Based on a shark-bitten partial skeleton of an immature sirenian (Metaxytherium cf. medium) from the middle Miocene of the Styrian Basin (Austria), we report on the oldest predator-prey interaction between tiger sharks and dugongs. The bite mark-bearing ribs and vertebrae are associated with seven teeth of Galeocerdo aduncus, which are otherwise rare in the fossil record of the Styrian Basin. The unique tooth morphology of the genus Galeocerdo is reflected by an unambiguous pattern of bite marks, which is repeatedly detected on one rib fragment. Similar bite marks were reproduced experimentally by using clay instead of bone. The obtained pattern is consistent with the observed bite marks on the sirenian rib fragment, which demonstrates that tiger sharks fed upon the Metaxytherium carcass. Furthermore, we also report on the first record of the angel shark Squatina sp. within the Styrian Basin.