Mesozoic that would move into their current positions during the next era. The climate of the Mesozoic was varied, alternating between warming and cooling periods. Overall, however, the Earth was hotter than it is today. Dinosaurs appeared in the Late Triassic and became the dominant terrestrial vertebrates early in the Jurassic, occupying this position for about 135 million years until their demise at the end of the Cretaceous. Birds first appeared in the Jurassic, having evolved from a branch of theropod dinosaurs. The first mammals also appeared during the Mesozoic, but would remain small—less than 15 kg (33 lb)—until the Cenozoic.
Middle Triassic there were ferns and mosses. Small dinosaurs began to appear like "Nyasasaurus" and the ichnogenus "Iranosauripus". Middle Triassic In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided. It spans the time between Ma and Ma (million years ago). The Middle Triassic is divided into the Anisian and Ladinian ages or stages. Formerly the middle series in the Triassic was also known as Muschelkalk. This name is now only used for a specific unit of rock strata with approximately Middle