Fossils of one of oldest dinosaurs on planet found in La Rioja

An Argentine research team from the National Scientific and Technical Research Council (CONICET) has discovered the almost complete skeleton of a long-necked dinosaur that lived around 230 million years ago, at a dig more than 3,000 metres above sea level in the foothills of the Andes in La Rioja Province.

The species, named Huayracursor jaguensis, dates back to the Late Triassic, a period of profound change in terrestrial ecosystems marked by the emergence of the first dinosaurs and the early predecessors of mammals.

The find, made at Quebrada de Santo Domingo, an area rich in fossils, was published in the prestigious Nature journal. Over the past decade, the site has yielded remains of other Triassic species such as Rinconsaurus and Cynodontia, helping scientists reconstruct the origins of modern terrestrial fauna.

“The place where we worked is as inhospitable as it is fascinating: strong winds, low temperatures and spectacular landscapes,” explained Martín Hechenleitner, a CONICET researcher at CRILAR (Regional Centre for Scientific and Technological Transfer Research of La Rioja) and the study’s lead author. The name Huayracursor pays tribute to the wind, while jaguensis refers to the nearby town of Jagüé, located some 40 kilometres from the site.

The scientists estimate that Huayracursor is between 230 and 225 million years old, placing it among the oldest known dinosaurs. “For over half a century, fossils of that age were confined to Ischigualasto (San Juan), southern La Rioja and southern Brazil. This discovery opens a new window onto an almost unexplored geological basin,” highlighted Agustín Martinelli, a CONICET researcher at the “Bernardino Rivadavia” Argentine Museum of Natural Sciences.

The new dinosaur belongs to the primitive Sauropodomorpha group, predecessors of the giant herbivores such as Argentinosaurus and Patagotitan. According to analyses, it is part of the Bagualasauria group, along with species that lived around the same time in southern Brazil.

“The remarkable thing about Huayracursor is that it combines a much longer neck and larger size than most of its contemporaries,” said Hechenleitner. “This shows that those traits appeared very early in the group’s evolution.”

Researchers recovered part of the skull, a complete vertebral series extending to the tail, and nearly complete front and rear limbs. Thanks to this exceptional state of preservation, they believe the fossil will serve as a key reference point for studying the early evolution of dinosaurs.

Despite its link to the Jurassic giants, Huayracursor was small — around two metres long and weighing roughly 18 kilogrammes.

The research team also included CONICET scientists Sebastián Rocher (UNLaR), Lucas Fiorelli (CRILAR), Jeremías Taborda (CICTERRA) and Julia Desojo (UNLP).

– TIMES/PERFIL