T. rex

# Evolutionary Timeline of T. rex Tyrannosaurus rex, one of the most iconic dinosaurs, evolved over millions of years from small, agile theropods to a massive apex predator. Its lineage traces back to early dinosaurs in the Triassic period, with key transitions driven by environmental changes like shifting climates, continental drift, and competition for resources. Major pressures included the need for efficient hunting in diverse ecosystems and adaptations to larger body sizes amid abundant prey during the Cretaceous. ### Key Milestones: - **Late Triassic (~230 million years ago):** Emergence of early theropods like *Coelophysis*, small bipedal ancestors with basic predatory traits. - **Jurassic Period (~150 million years ago):** Rise of larger theropods such as *Allosaurus*, introducing stronger jaws and improved locomotion under competitive pressures from other dinosaurs. - **Early Cretaceous (~125 million years ago):** Appearance of early tyrannosauroids like *Guanlong*, with developing tyrannosaurid features amid forested environments and evolving prey. - **Late Cretaceous (~80-66 million years ago):** Evolution of full tyrannosaurids, including *Tyrannosaurus rex*, driven by open plains, megaherbivore abundance, and climatic stability before the mass extinction event.