Taphonomical and palaeoecological investigation of the Late Cretaceous (Maastrichtian) Tuştea vertebrate assemblage (Romania; Haţeg Basin) - insights into a unique dinosaur nesting locality

According to the synthesis of all available field data two outstanding fossiliferous levels can be identified within the Tuştea locality, where Megaloolithus eggs and hadrosauroid hatchling material are preserved together, recognized here as two superposed nesting grounds. Such co-occurrence was considered controversial, since there is a long-standing and quasi-general consensus that eggs of the Megaloolithus oogenus were laid by titanosaurian sauropods. We present several alternative scenarios to account for the co-occurrence of Telmatosaurus hatchling remains and megaloolithid eggs in the nesting horizons and explore these alternative hypotheses by weighing the arguments supporting or contradicting them. The burden of evidence derived from our sedimentological, taphonomical and palaeoecological investigations at Tuştea is still in favour of the autochthony of the hatchlings, preserved within their own nesting grounds, whereas there is no such support for a titanosaurian origin of the Tuștea megaloolithid eggs.