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Eoraptor
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Illustration of Eoraptor, a small, slender, bipedal dinosaur from the late Triassic period, shown next to a modern bird for scale. Eoraptor has a long tail, sharp teeth, and measures about one meter (three feet) in length, highlighting its primitive features and its significance as a possible model for the common ancestor of all dinosaurs.
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Eoraptor

dinosaur
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Illustration of Eoraptor, a small, slender, bipedal dinosaur from the late Triassic period, shown next to a modern bird for scale. Eoraptor has a long tail, sharp teeth, and measures about one meter (three feet) in length, highlighting its primitive features and its significance as a possible model for the common ancestor of all dinosaurs.
Eoraptor Eoraptor, late Triassic dinosaur. A more primitive contemporary of Herrerasaurus, this tiny carnivore is close to what the common ancestor of all dinosaurs is thought to look like.

Eoraptor was one of the earliest known dinosaurs, dating back to the Late Triassic period, approximately 230 million years ago. Discovered in Argentina, Eoraptor is considered a primitive theropod, a subgroup of dinosaurs that includes all flesh-eating species.12

Eoraptor was a small, bipedal dinosaur, measuring about 1.2 meters (4 feet) in length. Paleontologist Paul Sereno named Eoraptor lunensis and determined it was the most primitive dinosaur because it lacked specialized features found in later species. This discovery supported the theory that all dinosaurs evolved from small, carnivorous, bipedal ancestors.13

Theropods, like Eoraptor, were diverse, ranging from crow-sized to giants like Tyrannosaurus rex. They were characterized by their hind legs for locomotion and mobile hands for grasping prey. Birds are descendants of theropods, making them members of this group.1

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4 Britannica Sources
  1. theropod
  2. dinosaur - Dinosaur ancestors
  3. dinosaur - Tetanurae
  4. Paul Sereno

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