New species of long-necked dinosaur discovered in mountains of Argentina
Paleontologists may have discovered when plant-eating dinosaurs evolved their long necks after a new species of sauropodomorph was found in Argentina.
The fossils of the new dinosaur species, named Huayracursor jaguensis, were found in the Santo Domingo Formation in the Andes of La Rioja province in northwestern Argentina, according to a paper Thursday in Nature.
H. jaguensis likely lived during the Late Triassic period, between 201 million and 237 million years ago.
Its neck bones show signs of extensions that may have resulted in the evolution of long-necked sauropodomorphs that were found in the region in later periods, the researchers said.
Drastic ecosystem changes took place during the Late Triassic, which led to a rise in diversification in several animal groups, including dinosaurs, early mammal relatives and a group that includes crocodiles, according to the paper.
Much of the evidence of early evolution in dinosaurs has been discovered in South America. Most of the key discoveries were made in Ischigualasto-Villa Unión Basin in western Argentina and the Paraná Basin in southern Brazil.
"This new fauna is the first to be recovered from the newly identified Northern Precordillera Basin," the researchers wrote.
However, H. jaguensis was discovered in a "distinct" region -- in the Andes mountain range about 2 miles above sea level.
Sauropodomorphs are herbivores known for their large size and long necks. The clade includes "brontosaurs," the well-known sauropod.
The earliest known Sauropodomorphs weighed about 22 pounds and had relatively short necks, but their body mass and neck elongation increased in their early evolution, suggesting that these key traits "emerged at the dawn of dinosaurs," according to the paper.
H. jaguensis is estimated to have measured at nearly 5 feet long and weighed about 40 pounds. It had a shorter neck compared to later sauropodomorphs, but its cervical vertebra showed signs of elongation.
The finding of H. jaguensis expands what researchers know about the diversity and geographic range of early dinosaurs, the researchers said.
