Jurassic dinosaurs of Transbaikalia and prospects of searching for them in Mongolia

Three Transbaikalian localities of dinosaur remains confined to concretions of the Tarbagatai Coal Field, coal deposits of the Arbagarskaya deposits, and tuffaceous sedimentary deposits of the Ukureiskaya Formation of the Olov Depression (Kulinda locality) are considered. In concretions, dinosaur fossils co-occur with fragmentary and complete skeletons of Salmo and Palaeoniscidae and tuffaceous sedimentary beds of volcanic lakes have yielded fossils of temporary inhabitants, such as notostracans, conchostracans, izophlebiid dragonflies, ostracods, and plants with index species of the Late Jurassic Unda–Daya Assemblage. These characteristics can be used in searching for Jurassic dinosaur burials in Mongolia. The horizons with concretions are known in the Tormkhon, Tevsh, Unduruhin, Anda-Khuduk, and Ulanereg formations. Remains of notostracans and izophlebiid dragonflies were recorded in the Ulugei Formation and terrigenous deposits of the Khalgyn-Ula locality and mass burials of large izophlebiid dragonflies and Palaeoniscidae have occur in the Dorogot Formation.