Taphonomy of the prosauropod dinosaur Sellosaurus, and its implications for carnivore faunas and feeding habits in the Late Triassic

The Stubensandstein (Upper Triassic, Norian) is a complex system of fluvial deposits in southwest Germany and yields one of the most diverse records of fossil vertebrates from the European continental Triassic. Taphonomic data from 17 partial skeletons of the prosauropod dinosaur Sellosaurus gracilis are presented, with emphasis on a recently rediscovered field sketch of one particular specimen. The preservational states and burial postures of individuals forming a practically monospecific prosauropod assemblage indicates in-situ preservation of single specimens, most likely by miring in unconsolidated fluvial sands covered by floodplain deposits. Shed teeth of carnivores and the mode of preservation suggest that one of the prosauropod carcasses was scavenged. At least two different types of predators, several individuals of a large indeterminate primitive archosaur and a phytosaur, left traces of their activities during scavenging on the carcass. The prosauropod-carnivore tooth assemblage provides the first evidence that deep-snouted phytosaurs with heterodont dentitions were capable of manipulating and feeding on large terrestrial prey. Moreover, scavenger–prey assemblages in the Norian of central Europe support the hypothesis that large carnivorous basal archosaurs (as represented for example by rauisuchians) were replaced by theropod dinosaurs in the Late Triassic.