Triassic Period Dinosaurs

Also Read: Jurassic Dinosaurs , Cretaceous Dinosaurs

Read 59+ Triassic Dinosaurs from the Early Triassic, Middle Triassic to the Late Triassic.

Each entry shows the exact time span, diet, and estimated size.

Click any name to open that species page, where you can read a full description, fossil history, size estimates / Comparisons, and source references.

For Detailed Time Period Refer to Time Period Page.

Dinosaur Diversity in the Triassic Period

Dinosaurs evolved from early archosaurs in the Triassic, at a time when archosaurs (the reptile group that includes dinosaurs, crocodilians, and pterosaurs) were replacing the previously dominant mammal-like reptiles.

These were small, bipedal creatures that likely hunted insects and small vertebrates. By the Late Triassic, dinosaurs had diversified into distinct lineages.

Theropods (carnivorous dinosaurs): Early theropods included genera like Herrerasaurus and Coelophysis. These two-legged predators had sharp teeth and claws, making them effective hunters in Triassic landscapes. They were generally small to medium in size compared to later Jurassic theropods.

Sauropodomorphs (herbivorous dinosaurs): Early sauropodomorphs like Plateosaurus (and related prosauropods) were among the first large herbivores. They had elongated necks for reaching vegetation and leaf-shaped teeth for browsing ferns and conifers. By the end of the Triassic, some basal sauropodomorphs (such as Riojasaurus) were already over 9 m long, foreshadowing the giant sauropods of later periods.

Ornithischians: True ornithischian dinosaurs (another major group) appear in the Late Triassic, though they were not yet dominant. Some early ornithischians or ornithischian relatives likely existed by the Norian age but remain poorly known.

End of the Triassic and Rise of the Dinosaurs

The Triassic Period ended with a major mass extinction around 201.3 million years ago (the Triassic–Jurassic extinction event). This crisis is thought to have been triggered by massive volcanic eruptions of the Central Atlantic Magmatic Province (CAMP), which released huge amounts of CO₂ and sulfur into the atmosphere.

The resulting climate change (global warming, acid rain, and ocean acidification) caused the collapse of many marine and terrestrial ecosystems. Sea levels rose and many marine invertebrates (like conodonts) disappeared.

On land, the extinction decimated most Triassic reptile groups. Virtually all non-dinosaurian archosaurs (such as rauisuchians, aetosaurs, and large croc-line archosaurs) went extinct.

Dinosaurs (and some early pterosaurs and crocodile-line archosaurs) were among the few survivors. With their competitors gone, dinosaurs faced little ecological opposition. This cleared ecological “playing field” allowed dinosaurs to radiate in the Jurassic, where they rapidly became the dominant land animals

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