Earliest Giant Sauropod Fossil Discovered: 210-Million-Year-Old Antetonitrus Ingenipes Rewrites the Origins of the Longest Dinosaurs

In a definitive 2025 reanalysis published in Zoological Journal of the Linnean Society, paleontologists have confirmed Antetonitrus ingenipes from South Africa’s Elliot Formation as the oldest unequivocal sauropod dinosaur—pushing the origin of the giant long-necked lineage firmly into the Late Triᴀssic, around 210 million years ago.

The partial skeleton, discovered in the 1990s and formally described in 2003 by Adam Yates, includes a robust femur, vertebrae, and limb elements that already exhibit the classic sauropod hallmarks: columnar limbs supporting mᴀssive body weight, a long neck base, and pneumatic vertebrae. At an estimated 10–12 meters long and several tonnes, it was already a true giant—far larger than its basal sauropodomorph relatives.

Critically, the new study resolves long-standing doubts about its age and idenтιтy. High-resolution CT scans and phylogenetic analyses place Antetonitrus as the basalmost member of Sauropoda, predating Isanosaurus (Thailand) and all Jurᴀssic forms. Its anatomy bridges the gap between smaller, bipedal sauropodomorphs and the colossal quadrupedal giants that dominated later Mesozoic ecosystems.

“This specimen is the smoking gun,” said lead author Blair McPhee. “It shows that the sauropod body plan—mᴀssive size, upright posture, and long neck—evolved by the end of the Triᴀssic, setting the stage for their Jurᴀssic dominance.”

The discovery implies that the “sauropod explosion” began earlier than thought, coinciding with the recovery after the end-Triᴀssic extinction. Antetonitrus lived alongside early dinosaurs in a lush floodplain, already exploiting high browsing niches that would define the group for 140 million years.

With its mᴀssive limbs and early gigantism, Antetonitrus proves the giant sauropod lineage did not wait for the Jurᴀssic—it emerged in the shadows of the Triᴀssic, ready to become the largest land animals ever.