240-million-year-old reptile fossil found in Brazil sheds light on archosaur origins

AI digestMimile.ai EditorialJuly 17, 2026 at 09:00 PM

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240-million-year-old reptile fossil found in Brazil sheds light on archosaur origins

Researchers in Brazil discovered a new reptile species, Silescelida acristata, dating to about 240 million years ago. The fossil, found in Rio Grande do Sul state, helps clarify the early evolution of archosauriforms, the group that gave rise to dinosaurs, crocodiles, and birds.

The Discovery

The fossil of Silescelida acristata was unearthed in Dona Francisca, central Rio Grande do Sul, within the UNESCO Quarta Colônia Geopark. The species lived during the Middle Triassic Period, shortly after the Permian–Triassic extinction event 252 million years ago. The specimen preserves mainly limb bones, including a femur that indicates a semi-erect posture.

Evolutionary Significance

Silescelida acristata belongs to a lineage closely related to the ancestors of archosaurs, which include dinosaurs, crocodiles, and birds. Its semi-erect stance allowed more efficient locomotion, reducing drag. The study, published in Scientific Reports, was conducted by researchers from CAPPA/UFSM, UFRGS, and PUCRS.

What's Next

Further excavations at the Quarta Colônia Geopark may yield additional specimens. It remains unclear how Silescelida acristata fits into the broader archosauriform family tree.

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240-million-year-old reptile fossil found in Brazil sheds light on archosaur origins

phys.org

Phys.org

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240-million-year-old reptile fossil found in Brazil sheds light on archosaur origins

The Discovery

Evolutionary Significance

What's Next

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