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Rare ‘Light-Footed’ Dinosaur Discovered in Australia for the First Time

A single vertebra spotted by a dig volunteer was identified as a strange, slender-necked dinosaur called an elaphrosaur

An artist’s rendering of what an elaphrosaur may have looked like. (Ruairidh Duncan)
smithsonianmag.com

A previously mysterious fossil found in Victoria, Australia, has been identified as a rare, beaked dinosaur called an elaphrosaur, according to new research. Paleontologists have dated the specimen, first uncovered by a volunteer digger, to the Early Cretaceous, roughly 110 million years ago.

The name elaphrosaur means light-footed lizard, reports Sian Johnson for ABC News. Members of this small group of dinosaurs have long, slender necks, short arms and slight builds overall, explains Stephen Poropat, a paleontologist at Swinburne University of Technology and the lead researcher on the new paper in a statement.

“As dinosaurs go, they were rather bizarre. The few known skulls of elaphrosaurs show that the youngsters had teeth, but that the adults lost their teeth and replaced them with a horny beak. We don’t know if this is true for the Victorian elaphrosaur yet—but we might find out if we ever discover a skull,” Poropat adds.

Their toothsome youth suggests they may have gone through some kind of dietary shift with age, Poropat tells John Pickrell of the Guardian. But as their lack of fearsome chompers in adulthood suggests, elaphrosaurs were probably omnivores despite being theropods, which are cousins to Tyrannosaurus rex and other famous bygone carnivores, Steve Bursatte, a paleontologist at the University of Edinburgh who was not involved in the research, tells the Guardian. This particular elaphrosaur was probably just shy of seven feet long from nose to tail, according to the statement.

Elaphrosaurs are “really rare,” Poropat tells the Guardian. The elaphrosuars are a sparse lineage with just three named species that have been discovered in Tanzania, China and Argentina. “This is the first record of the group in Australia, and only the second Cretaceous record worldwide,” Poropat says.

Bursatte says the discovery of this specimen in Australia “greatly expands the range of these animals... They were probably a widespread, and perhaps even global, group of dinosaurs, which we haven’t yet appreciated because of the scanty clues they left behind.”

dinosaur vertebra
A fossilized vertebra, discovered by a volunteer digger in 2015 near Victoria, Australia, and subsequently identified as a type of dinosaur called an elaphrosaur. (Stephen Poropat )

The fossil at the center of the new research, published earlier this month in the journal Gondwana Research, was first unearthed by dig volunteer Jessica Parker in 2015, per the statement. Parker spotted a “strange, delicate bone” roughly two inches long at a Cretaceous fossil bed known as Eric the Red West, near Cape Otway in Victoria.

Researchers initially pegged the fossil as a vertebra belonging to a pterosaur, a type of flying reptile, but closer examination revealed its surprising identity.

The slender, swift-footed elaphrosaur is also unique among its brethren for when it lived. Its relatives Elaphrosaurus from Tanzania and Limusaurus from Chin date from the late Jurassic (160-145 million years ago), but the Australian elaphrosaur lived around 40 million years later during the Early Cretaceous.

At that time, around 110 million years ago, Australia was located inside the Antarctic Circle and the fossil bed at Eric the Red West was home to a swiftly flowing river bordered by lush plant life, Poropat tells ABC News.

"There were conifer trees, things like modern-day monkey puzzles. There were ferns and lots of flowering plants," he continues. The ancient riverbed has also preserved a jumble of bones from meat-eating dinosaurs, plant-eating dinosaurs, turtles and fish alongside the elaphrosaur, suggesting it was part of a diverse ecosystem.

The researchers are anxious to return to the Eric the Red West fossil bed soon, according to the statement, but their plans are on hold due to COVID-19 and had already been delayed once due to fire season.

Poropat praised the contribution of Parker, the volunteer who found the fossil. "As this story tells, one bone can change our understanding completely," he tells ABC News. "If it belongs to a group of animals that we didn't know was represented in Victoria, let alone Australia before, it can shape our understanding of the fauna."

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