similar to semiarid and temperate to warm, dry woodlands or bushlands. The open environment allowed more cursorial (adapted for running) and large animals to occur, contrasting with the earlier conditions during the late Early Miocene, with its well-developed forests with tree-dwelling animals. Forests would then have been restricted to valleys of the cordillera mountain ranges, with few tree-dwelling species. This change happened progressively during the earlier Friasian stage. The transition towards more arid landscapes would have happened simultaneously with climate changes that corresponded to the Middle Miocene Climate Transition, a global cooling event which had a drying effect on continents. The Collón Curá Formation of Argentina has provided a wide assemblage of mammals, including at least 24 taxa such as the xenarthrans Megathericulus, Prepotherium, Prozaedyus, and Paraeucinepeltus, the notoungulate Protypotherium, the astrapothere Astrapotherium, the sparassodonts Patagosmilus and Cladosictis, the marsupial Abderites, the primate Proteropithecia, and rodents such as Maruchito, Protacaremys, Neoreomys, and Prolagostomus. In addition to the mammals that characterize sediments of this age, there are also a few fossils of birds, reptiles, amphibians, and fish. References External links Phorusrhacidae Extinct flightless birds Prehistoric bird genera Miocene birds of South America Colloncuran Neogene Argentina Fossils of Argentina Fossil taxa described in 2007 Prehistoric birds of South America