Wed, Jul 11, 2018 - Page 6 News List

Giant bones prompt rethink of Triassic period dinosaurs

AFP, BUENOS AIRES

A reconstruction of the sauropodomorph dinosaur Ingentia prima shows an improved avian-like respiratory system with developed cervical air sacs in a handout image provided on Monday.

Photo: Reuters

Giant dinosaurs lived on Earth much earlier than previously thought, according to a team of excavators in Argentina who discovered the remains of a 200 million-year-old species.

The species, baptized Ingentia prima, was about three times the size of the largest Triassic dinosaurs from its era.

It was discovered in the Balde de Leyes dig site in San Juan Province, 1,100km west of the capital, Buenos Aires.

The find was published on Monday in the specialist journal Nature Ecology and Evolution and revealed in Argentina by the National University of La Matanza’s Scientific Dissemination Agency.

“As soon as we found it, we realized it was something different. We found a shape, the first giant one among all the dinosaurs. That’s the surprise,” said Cecilia Apaldetti, a government and National University of San Juan researcher.

Excavators found several vertebrae from the neck and tail, as well as fore and hind leg bones.

The species “exhibits a growth strategy that was unknown until now and indicates that gigantism originated much earlier than was thought,” said Apaldetti, the study’s coauthor.

These were “herbivore dinosaurs, quadrupeds, easily recognizable by their very long neck and tail, and from the sauropod group,” she added.

Before this discovery, it was thought that gigantism developed during the Jurassic period, about 180 million years ago.

Coauthor Ricardo Martinez said he believes I. prima is from “a late Triassic period, possibly 205 million years” ago.

The Triassic period extended from about 250 million to 200 million years ago and the Jurassic from 200 million to 145 million years ago.

The team has been studying the Triassic period, when dinosaurs were just beginning to appear. The first ones were small, but as they evolved they tended towards gigantism to defend themselves against predators.

I. prima was the first dinosaur species to reach gigantism, and even though it was a long way from the 70 tonnes of the biggest sauropods at the end of the Cretaceous period (145 million to 66 million years ago), the speed of bone tissue accumulation was greater than that of species from its era and the biggest giants that lived in southern Argentina’s Patagonia, the scientists said.

Its bone fragments displayed cyclical and seasonal growth, with a different kind of tissue to other sauropods, which allowed it to grow very quickly, they said.

It is believed that the species grew to 8m to 10m tall — the specimen found was a growing youth measuring 6m to 7m — and weighed about 10 tonnes, equal to two or three African elephants.

Another of the species’ features was air cavities in its bones, making it lighter and promoting growth.

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