Enter OTP to View Content
Evolutionary Lineage of Archosauria
| Category | Description | Examples |
|---|---|---|
| Archosauria (Common Ancestor) | Archosaurs, a group of reptiles from the early Triassic (~250 million years ago), are the common ancestor of crocodilians, pterosaurs, and dinosaurs. | None |
| Branches | ||
| Crocodylomorpha (Crocodilians) | Crocodiles and their relatives diverged early (~230 million years ago). Evolved independently but retained traits of their ancient archosaur ancestors. | Crocodiles, Alligators |
| Ornithodira | This lineage gave rise to both pterosaurs and dinosaurs. | None |
| Pterosauria (Pterosaurs) | Diverged from the common ancestor of dinosaurs in the Triassic (~228 million years ago). | Pteranodon: A flying reptile (~6-meter wingspan) from the late Cretaceous. |
| Dinosauria (Dinosaurs) | Appeared ~230 million years ago, divided into two major clades: | |
| A. Ornithischia (“Bird-Hipped Dinosaurs”) | Herbivorous dinosaurs with pelvises resembling modern birds. | |
| Triceratops: Lived in the late Cretaceous (~68-66 million years ago). It had three horns and a bony frill. Adapted for defense and display. | Triceratops | |
| Stegosaurus: Lived in the Jurassic (~155-150 million years ago). Featured large, bony plates for thermoregulation or display. | Stegosaurus | |
| B. Saurischia (“Lizard-Hipped Dinosaurs”) | Further divided into two groups: | |
| 1. Sauropodomorpha (Long-Necked Dinosaurs) | Long-necked herbivorous dinosaurs. | Brachiosaurus: A giant, long-necked herbivore from the Jurassic (~154-153 million years ago). |
| 2. Theropoda (Bipedal Predators + Birds) | Bipedal carnivores, including the ancestors of modern birds. | |
| Tyrannosaurus rex: Apex predator of the late Cretaceous (~68-66 million years ago), with a massive skull and strong legs. | Tyrannosaurus rex | |
| Archaeopteryx: Lived in the late Jurassic (~150 million years ago). A transitional species with feathers, clawed wings, and teeth. | Archaeopteryx | |
| Modern birds: Evolved from small, feathered theropods during the Jurassic and Cretaceous periods. | Various modern bird species |
