Brazilian fossil finds and turtle study reshape understanding of reptile evolution

Researchers in Rio Grande do Sul, Brazil, identified a new 240‑million‑year‑old reptile species, Silescelida acristata, from Triassic rocks in the municipality of Dona Francisca. The discovery, published in Scientific Reports, adds a semi‑erect, four‑legged predator to the record of early archosauriforms and extends the known geographic range of the rare Euparkeriidae group beyond Africa, Asia and Europe.

A separate study published in Current Biology, led by scientists from the American Museum of Natural History, examined 226 fossil specimens using high‑resolution X‑ray tomography. The analysis argues that turtles share a closer common ancestor with crocodiles and birds—members of the arcossauromorph clade—rather than with the previously favored early reptile Eunotosaurus. Supporting evidence includes the presence of a laterosphenoid bone, specific foot bone morphology, and a distinctive stapes structure.

Both findings challenge longstanding views on the evolutionary pathways of major reptile groups, highlighting the complexity of early vertebrate diversification and underscoring Brazil’s and the United States’ contributions to paleontological research.