Baby dinosaur fossil Australia’s smallest sauropod – at 4.2 tonnes!

A dinosaur discovered in Queensland is the smallest sauropod found in Australia. The 95-million-year-old “baby” has been nicknamed “Ollie” and is the first juvenile sauropod found in the country. Though still a child when he died, Ollie would have measured 11 metres in length and weighed an estimated 4.2 tonnes – as much as an adult elephant!

Sauropods were long-necked dinosaurs and are among the largest land animals of all time. Ollie is the third Diamantinasaurus matildae individual found and his species was part of a group of sauropods called titanosaurs found mostly in Africa, South America and Australia. Though adult Diamantinasuarus would have reached about 15m and weighed 15 to 20 tonnes, other titanosaurs are thought to have grown to more than 35m and been as much as 100 tonnes in weight.

More on dinosaurs: Scientists claim fossil could be from the day dinosaurs went extinct

The announcement of Ollie as Australia’s smallest sauropod comes less than a year after researchers declared they had found Australia’s largest. That specimen, “Cooper,” found about 400km south of Ollie, was an Australotitan cooperensis which would have been 30m long, 6m high at the hip, and weighed up to 70 tonnes – more than 16 times Ollie’s size.

Ollie was discovered in 2012 by a sheep grazier near the western-Queensland town of Winton. The Winton Formation where Ollie was found is made up of sandstones, siltstones and claystones formed during the late Cretaceous period. What is now sheep and cattle grazing country, 90 million years ago would have been a dinosaur habitat made up of rivers, freshwater pools, swamps and coastal estuaries.

Diamantinasaurus like Ollie may have eaten conifers, angiosperms, ginkgoes, cycads, ferns and horsetails.

Samantha Rigby, a palaeontologist and masters student at Swinburne University in Melbourne, is the lead author of a paper published about Ollie this month in the Journal of Vertebrate Paleontology.

Palaeontologist Samantha Rigby with one of Ollie’s vertebrae. Supplied: Australian Age of Dinosaurs

“Even though we’re talking about a little baby, he’s not actually that small,” Rigby told the Australian Broadcasting Corporation (ABC). While an exact cause of death is unknown, researchers believe it is likely Ollie became stuck in mud near a watering hole and sank, leaving the fossils below the mud well preserved.

Dozens of fossils were excavated, including vertebrae, ribs, a scapula, a humerus, a thumb claw and a femur.

Ollie’s dorsal vertebra. Source: Journal of Vertebrate Paleontology

“Some of the bones in his body weren’t fused, so we know that (Ollie) was a juvenile,” Rigby says. “I spent a really long time comparing Ollie with all of the adult specimens here in Winton and we found that Ollie is not an exact copy of the adult.”

The find provides evidence for the unsurprising, but nonetheless important, fact that juvenile dinosaurs were not just small versions of adults. Like humans and other modern animals, their bodies would have changed as they grew.

“The limb bones of this juvenile titanosaur grew at a more rapid rate than its back and shoulder bones. The bones are also narrower in width when compared with the robust limb bones of an adult Diamantinasaurus. Ollie’s limbs were a lot more overgrown and as he grew up, he grew into his limbs. He would have looked a bit weird with really long legs and a small body,” she adds.

In other palaeontology news, giant dolphin-like marine reptiles which swam in oceans 200 million years ago while dinosaurs roamed the Earth have been found 2800m above sea level.

A paper released in the Journal of Vertebrate Paleontology today, examines the fossils unearthed in the Swiss Alps between 1976 and 1990. Over millions of years, the rising of the Alps has raised the ancient ocean floors to surprising heights, revealing three new ichthyosaur species in the new study.

The fossils include the largest ichthyosaur tooth ever found. The width of the tooth root is twice as large as any known aquatic reptile. The previous largest belonged to a 15m-long ichthyosaur. The new animal could have been more than 20m in length and weighed 80 tonnes, rivalling a sperm whale in size, researchers believe. “The tooth is particularly exciting,” explains lead author and Professor at the University of Bonn, Martin Sander. “Because this is huge by ichthyosaur standards: Its root was 60 millimetres in diameter – the largest specimen still in a complete skull to date was 20mm and came from an ichthyosaur that was nearly 18m long.”

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