Monograph: Theropod dinosaurs from the Late Jurassic of Tendaguru (Tanzania)

The Tendaguru Formation of south-eastern Tanzania has yielded the only diverse theropod fauna known from the Late Jurassic of Gondwana. Theropod remains have been recovered mainly from two members of the formation, the Middle and Upper Dinosaur members, which span from the Kimmeridgian to the latest Tithonian or earliest Cretaceous. Here, four of the described taxa and additional isolated remains from this formation are reviewed and evaluated. Labrosaurus(?) stechowi Janensch, and Megalosaurus(?) ingens Janensch, are based on isolated teeth that do not show any unique derived characters, so these taxa are regarded as nomina dubia. Nevertheless, the teeth show character combinations indicative of ceratosaurid and carcharodontosaurid relationships, respectively. Ceratosaurus? roechlingi Janensch was based on associated fragmentary remains, which probably represent more than a single taxon. None of the type material shows diagnostic characters, so the species is a nomen dubium, and a middle caudal vertebra with possibly ceratosaurid affinities is designated as the lectotype. Allosaurus(?) tendgurensis Janensch is based on an isolated, poorly preserved basal tetanuran tibia, which cannot be diagnosed, so the species is also a nomen dubium. A new taxon, Veterupristisaurus milneri gen. et sp. nov., is based on diagnostic caudal vertebrae from the Middle Dinosaur Member. These elements show carcharodontosaurid synapomorphies and, within this clade, share a unique derived character with the genus Acrocanthosaurus. In total, theropod material from the Tendaguru Formation indicates the presence of at least seven different species of theropods, including the ceratosaurian Elaphrosaurus bambergi Janensch, a probable ceratosaurid, a small abelisauroid, a probable abelisaurid, a small, noncoelurosaurian tetanuran, a possible megalosauroid and a carcharodontosaurid. Theropod faunas from the Middle and Upper Dinosaur members might differ slightly, but are similar in general taxonomic composition. In broad systematic terms, the theropod fauna from Tendaguru shows greater similarities to Cretaceous Gondwanan theropod faunas than with contemporaneous fauna from the North American Morrison Formation, indicating that the complex evolutionary and biogeographical history of Cretaceous Gondwanan theropod faunas can only be understood in the light of their Jurassic origins.