Pathologies of non-marine bivalve shells from the Late Triassic of Poland

Shells of Late Triassic non-marine bivalves from Lisowice (Lipie Slaskie clay pit, southern Poland), which co-occur with remains of several vertebrate taxa (mammal-like reptiles, carnivorous dinosaurs, pterosaurs, temnospondyl amphibians, hybodont sharks, dipnoan and ganoid fish), bear evidence of pathologies. Distribution, dimension and shape of some of these injuries (radiate tooth marks) closely match the dental morphology of lungfish (here probably represented by the genus Ceratodus). Thus, we interpret these pathologies as evidence of unsuccessful predatory attack on bivalves by this fish. This interpretation is also consistent with modern examples of such behaviour among lungfish. The feasibility that other culprits caused other pathologies (shell scarring and wedges) on the bivalves analysed is also discussed. Discovery of these traces constitutes important evidence of predator prey interaction, which provides 'fingerprints' of trophic structure within this Late Triassic freshwater ecosystem.