Researchers specializing in paleontology have recently brought to light a novel collection of fossils dating back to the Triassic period, discovered at the Quebrada Santo Domingo locale within the Northern Precordillera Basin, situated in the northwestern region of Argentina. Among these significant findings are a remarkably preserved, almost complete skeleton of a previously uncatalogued sauropodomorph dinosaur species, alongside various specimens representing cynodonts, rhynchosaurs, and aetosaurs.
Huayracursor jaguensis. Image credit: Jorge Blanco.
This newly identified species inhabited the geographical area now known as Argentina during the Carnian stage of the Late Triassic epoch, approximately 230 million years in the past.
Designated as Huayracursor jaguensis, this dinosaur is recognized as an early and rudimentary representative of the Sauropodomorpha evolutionary lineage.
The ancient creature possessed a notably elongated neck and attained a greater size compared to the majority of its contemporaries.
Dr. Martin Hechenleitner, a paleontologist affiliated with the Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja and CONICET, along with his colleagues, stated, “The Carnian epoch (spanning from 237 to 227 million years ago) constitutes a pivotal period in the evolution of tetrapods, providing the earliest documented evidence for numerous significant evolutionary branches, including dinosaurs.”
He further elaborated, “Subsequent to the Carnian pluvial event, dinosaurs underwent substantial diversification, swiftly solidifying their dominance throughout the remainder of the Mesozoic Era.”
“The majority of early fossil records originate from a limited number of thoroughly studied geological sites in South America, specifically within the Ischigualasto-Villa Unión Basin in western Argentina and the Paraná Basin in southern Brazil.”
“These discoveries have yielded a rich array of early dinosaur types, encompassing ornithischians, herrerasaurids, theropods, and sauropodomorphs.”
“Although sauropodomorphs exhibit the greatest taxonomic variety, nearly all of them were characterized as small, short-necked, bipedal forms, with only fragmentary exceptions.”
“Despite advancements in our comprehension of Carnian tetrapod faunas, no assemblages containing dinosaurs have been unearthed beyond the traditionally recognized geological regions.”
Selected bones of the Huayracursor jaguensis holotype. Image credit: Hechenleitner et al., doi: 10.1038/s41586-025-09634-3.
Dr. Hechenleitner and his research associates identified the fossilized remains of Huayracursor jaguensis and several other Triassic fauna within the Santo Domingo Formation at Quebrada Santo Domingo. This site is a remote location in the Andes Mountains of the La Rioja province, situated in northwestern Argentina.
The research team reported, “This newly discovered fauna represents the first evidence recovered from the recently designated Northern Precordillera Basin.”
The paleontologists further noted, “Current discoveries encompass hyperodapedontine rhynchosaurs, traversodontid and probainognathian cynodonts, aetosaurs, and a minimum of two sauropodomorph dinosaur species, all indicative of a Carnian age.”
“Among the sauropodomorphs, Huayracursor jaguensis offers the earliest confirmation of concurrent increases in body mass and neck length within Sauropodomorpha, suggesting that these defining characteristics emerged at the very inception of dinosaur evolution.”
“This finding significantly expands the known diversity and geographical distribution of early dinosaur populations, thereby enhancing our understanding of sauropodomorph development during the Carnian period.”
The scientific description of the Huayracursor jaguensis discovery is detailed in a research publication featured in the esteemed 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
