Paleontologists Discover New Species of Triassic Long-Necked Dinosaur

Oct 16, 2025 by Enrico de Lazaro

Paleontologists have unearthed a new assemblage of Triassic fossils at the Quebrada Santo Domingo site of the Northern Precordillera Basin in northwestern Argentina. Their discoveries include a nearly complete skeleton of a previously unknown sauropodomorph dinosaur species as well as several cynodonts, rhynchosaurs, and aetosaurs.

Huayracursor jaguensis. Image credit: Jorge Blanco.

Huayracursor jaguensis. Image credit: Jorge Blanco.

The newly-discovered species lived in what is now Argentina during the Carnian age of the Late Triassic epoch, about 230 million years ago.

Named Huayracursor jaguensis, this dinosaur was an early and primitive member of the clade Sauropodomorpha.

The ancient animal had a considerably longer neck and was larger than most of its contemporaries.

“The Carnian age (237 to 227 million years ago) marks a crucial interval in tetrapod evolution, preserving the earliest records of several major clades, including dinosaurs,” said Dr. Martin Hechenleitner, a paleontologist at the Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja and CONICET, and colleagues.

“Following the Carnian pluvial episode, dinosaurs experienced significant radiation, rapidly establishing their dominance for the remainder of the Mesozoic Era.”

“Most early records come from a small number of well-studied localities in South America, in the Ischigualasto-Villa Unión Basin in western Argentina and the Paraná Basin in southern Brazil.”

“These sites have yielded diverse early dinosaurs, including ornithischians, herrerasaurids, theropods and sauropodomorphs.”

“Although the sauropodomorphs are the most taxonomically diverse, almost all were (with fragmentary exceptions) small, short-necked, bipedal forms.”

“Despite advances in our understanding of Carnian tetrapod faunas, no dinosaur-bearing assemblages have emerged outside traditional units.”

Selected bones of the Huayracursor jaguensis holotype. Image credit: Hechenleitner et al., doi: 10.1038/s41586-025-09634-3.

Selected bones of the Huayracursor jaguensis holotype. Image credit: Hechenleitner et al., doi: 10.1038/s41586-025-09634-3.

Dr. Hechenleitner and co-authors discovered the fossilized remains of Huayracursor jaguensis and several other Triassic animals in the Santo Domingo Formation at Quebrada Santo Domingo, a remote locality in the Andes of La Rioja province, northwestern Argentina.

“This new fauna is the first to be recovered from the newly identified Northern Precordillera Basin,” the paleontologists said.

“Current findings include hyperodapedontine rhynchosaurs, traversodontid and probainognathian cynodonts, aetosaurs, and at least two sauropodomorph dinosaurs, indicating a Carnian age.”

“Among sauropodomorphs, Huayracursor jaguensis provides the earliest evidence of synchronous body mass increase and neck elongation in Sauropodomorpha, suggesting that these key traits emerged at the dawn of dinosaurs.”

“This finding expands the known diversity and geographic range of early dinosaur faunas and expands our understanding of sauropodomorph evolution in the Carnian age.”

The discovery of Huayracursor jaguensis is described in a paper in the journal Nature.

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E.M. Hechenleitner et al. A long-necked early dinosaur from a newly discovered Upper Triassic basin in the Andes. Nature, published online October 15, 2025; doi: 10.1038/s41586-025-09634-3

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