Ecosystems recovered from mass extinction as the first dinosaurs and mammals appeared. Pangaea was a single giant landmass, and an end-Triassic extinction paved the way for dinosaur dominance.
Explore the Triassic Earth in 3D →From 234 to 232 million years ago, warming reshaped Pangaea’s water cycle. Geological records and climate models suggest stronger rainfall in parts of eastern Pangaea and polar regions, but drier continental interiors. Conditions varied across places and time during this pluvial episode; rain did not fall continuously worldwide.
Unquestioned early dinosaur fossils date to about 230 million years ago, in the Late Triassic, but already represent several lineages. A 2025 analysis accounting for missing fossil records suggested an earlier origin in low-latitude Gondwana. That proposed birthplace remains a model-based hypothesis, not a fossil-confirmed location.
Around 225 million years ago, small cynodont relatives combined mammal-like traits in different ways. A 2024 CT study showed a mammalian-style jaw joint arose independently in one lineage. Such relatives and early mammaliaforms should not all be equated with crown mammals: the common ancestor of living mammals and its descendants.
A Triassic impact left a vast crater in present-day Québec; studies also place its age near 215.4 million years. Today’s ring-shaped lake is much younger: damming joined earlier lakes into a reservoir, revealing the ancient crater’s outline.