Paleontologists have discovered a new group of Triassic fossils at the Quebrada-Santo Domingo site in the Northern Precordillera basin in northwestern Argentina. Their discoveries include a nearly complete skeleton of a previously unknown species of sauropodomorph dinosaur, as well as several cynodonts, rhynchosaurs, and aetosaurs.
The newly discovered species lived in what is now Argentina during the Carnian period of the Late Triassic, about 230 million years ago.
Named Huyracursor jaguensisthis dinosaur was an early and primitive member of the clade Sauropodomorpha.
The ancient animal had a significantly longer neck and was larger than most of its contemporaries.
“The Carnian Age (237 to 227 million years ago) marks a decisive interval in the evolution of tetrapods, representing the earliest records of the largest tissues, including dinosaurs,” said Dr. Martin Hechenleitner, paleontologist at the Central Regional Research Center Centífis y Transferencia Tecnollógica de la Rioja and Conicet, and his colleagues.
“After the Carnian pluvial episode, dinosaurs experienced significant radiation, quickly establishing their dominance for the remainder of the Mesozoic era.”
“Most of the early records come from a small number of well-studied sites in South America, the Ischigualasto-Villa Union Basin of western Argentina and the Paraná Basin of southern Brazil.”
“These sites were home to a variety of early dinosaurs, including ornithischians, herrerasaurids, theropods and sauropodomorphs.”
“Although sauropodomorphs are the most taxonomically diverse, almost all of them (with fragmentary exceptions) were small, short-necked bipedal forms.”
“Despite progress in our understanding of the tetrapod fauna of the Carnian Islands, no dinosaur communities have emerged outside of traditional units.”
Selected Bones Huyracursor jaguensis holotype. Image credit: Hechenleitner etc.., two: 10.1038/s41586-025-09634-3.
Dr. Hechenleitner and co-authors discovered fossilized remains Huyracursor jaguensis and several other Triassic animals Santo Domingo Formation in Quebrada Santo Domingo, a remote place in the Andes province of La Rioja, in northwestern Argentina.
“This new fauna is the first to be discovered in the recently identified Northern Precordillera basin,” the paleontologists said.
“Current finds include hyperodapedontine rhynchosaurs, traversodontid and probainognathine cynodonts, aetosaurs, and at least two sauropodomorph dinosaurs, indicating a Carnian age.”
“Among the sauropodomorphs Huyracursor jaguensis provides the earliest evidence of synchronous increases in body mass and neck elongation in sauropodomorphs, suggesting that these key traits arose at the dawn of the dinosaurs.”
“This find expands the known diversity and geographic range of early dinosaur faunas and expands our understanding of the evolution of sauropodomorphs during the Carnian era.”
Opening Huyracursor jaguensis described in paper in the magazine Nature.
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EM. Hechenleitner etc.. An early long-necked dinosaur from a recently discovered Upper Triassic basin in the Andes. Naturepublished online October 15, 2025; doi: 10.1038/s41586-025-09634-3
