230-Million-Year-Old Dinosaur Fossil Discovery Redefines Sauropod Evolution Timeline
October 16, 2025
A groundbreaking discovery of a 230-million-year-old dinosaur fossil named Huayracursor jaguensis from Argentina has reshaped our understanding of dinosaur evolution, indicating that the development of long-necked sauropods began earlier than previously believed.
This herbivorous dinosaur, living at the end of the Triassic period, was about two meters long and weighed roughly 18 kilograms, showcasing early adaptations that hint at the gradual evolution of the iconic sauropod body plan.
The fossil, which includes a nearly complete skeleton with parts of the skull, the entire spine to the tail, and most limb bones, was discovered in the Andes mountain range and published in the journal Nature, underscoring its scientific significance.
Huayracursor's anatomical features suggest early experimental adaptations related to ecological strategies such as foraging and browsing, providing clues about the evolution of neck elongation and gigantism in sauropods.
This discovery bridges a crucial gap in dinosaur evolution, showing an intermediate stage in body size and neck elongation that links small-bodied Carnian sauropodomorphs to larger, long-necked genera of the Norian stage.
The find also offers valuable insights into the ecosystem's complexity during the Late Triassic, where early dinosaurs coexisted with herbivorous aetosaurs, rhynchosaurs, and cynodonts, revealing intricate trophic interactions.
The fossil's geological context provides a detailed temporal framework for studying evolutionary rates and biotic interactions during a period marked by climatic fluctuations and faunal turnovers.
This discovery challenges existing timelines of dinosaur development, suggesting that the origins of giant sauropods like Argentinosaurus and Patagotitan may trace back over 100 million years earlier to smaller ancestors.
The find expands the known geographic distribution of dinosaur faunas in Gondwana, demonstrating that diverse ecosystems existed across different regions, not just in well-studied basins like Ischigualasto and Paraná.
Named Huayracursor in homage to the wind and Jaguensis after the nearby ancient village, this species highlights the cultural connection to its Argentine origins.
Discovered in 2018 at an altitude of 3,000 meters in La Rioja province by a team from CONICET, the site’s challenging environment with high altitude and extreme weather conditions underscores the region’s significance for paleontological research.
The discovery, led by a team from CONICET and published in Nature, emphasizes the importance of South American fossil sites like the Ischigualasto Formation for understanding early dinosaur evolution and diversification.
Summary based on 10 sources
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Sources

New Scientist • Oct 15, 2025
Dinosaur fossil rewrites the story of how sauropods got long necks
Phys.org • Oct 16, 2025
One of world's oldest dinosaurs discovered in Argentina
BIOENGINEER.ORG • Oct 16, 2025
Long-Necked Early Dinosaur Unearthed in Andes