Mammals that coexisted with dinosaurs

Seven fossil sites of Mesozoic mammals have been discovered in Russia: four in Western Siberia (one Middle Jurassic and three Early Cretaceous), one in European Russia (Middle Jurassic), one in Transbaikalia (Early Cretaceous), and one in the Far East (Late Cretaceous). The specimens represent most of the ancient mammal groups known to have lived in the northern hemisphere. The finds suggest that, with further exploration, Russia may become a major source of data on Mesozoic mammals.