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Opal-filled fossils reveal new dinosaur species



In a dazzling discovery, fossils brought from a mine at Wee Warra near the Australian outback city of Lightning Ridge are among the newly named dinosaur species Weewarrasaurus pobeni . The animal, about the size of a Labrador Retriever, walked on its hind legs and had beaks and teeth to nibble the vegetation.

A species known as ornithopod dinosaur, Weewarrasaurus moved into flocks or small groups for protection. The fossil contributes to the growing evidence that the herbivorous fauna of the southern hemisphere consisted of quite different living beings than the Cretaceous herbivores of North America, such as the numerous horned relatives of Triceratops and the Hadrians of duck brood.

But perhaps the most striking feature of this fossil, described today in an article published in the journal PeerJ is that it is made up of Opal, a precious gemstone that makes up this part of the state of New South Wales is known.

The right lower jaw of Weewarrasaurus shows the rainbow colors of opal in the fossil.

"As a paleontologist, I am interested in anatomy ̵

1; the bone and in this case the teeth," says lead author Phil Bell of the University of New England in Armidale, New South Wales.

"But if you work in Lightning Ridge," Bell says, "You can not ignore th The fact that some of these things are preserved in spectacular opal, these are all the colors of the rainbow. "

Like No Place on Earth

Hundreds of small mines make up this dry landscape 450 miles northwest of Sydney. Dinosaur fossils are rarely found here. Bell says it's a miracle to have a fossilized jaw exposed with teeth. (See photos of an opal mining community that lives underground in South Australia.)

"It's a truly unique area," he adds. "There is no place in the world where dinosaurs are preserved in beautiful opal." This almost 100-million-year-old specimen was hewn out of the colorful gemstone that formed out of the concentration of silicic acid over the eons. Rich underground solutions.

The fossil was found in 2013 by Adelaide opal trader Mike Poben, for whom the new species was named. He had bought a bag of coarse opal from the miners and searched him for fossils, as he always does. An unusual piece caught his eye.

"A voice in the back of my head said teeth," he recalls. "I thought, oh my god, if I have teeth here, this is a jawbone."

Poben clung to the possibly toothy specimen and sent out the remaining opal with a so-called runner whose job it was drive around Lightning Ridge and try to find a buyer. After nine days, the runner returned the bag unsold, and Poben took a closer look at the contents.

"I found another piece of bone, smaller with sockets, turned it over and then things really started to explode in my head. "He says," As I stringed the pieces together, I realized I had two pieces from the same jaw bone. "

Bell, the paleontologist who would literally describe the dinosaur, says his own jaw is the first time Poben then donated the fossil to the Australian Opal Center, a Lightning Ridge Museum with the world's largest collection of opalescent fossils.

Dinosaurs of the Southern Supercontinent

Weewarrasaurus contributes to a fast-growing range of dinosaurs from the eastern part of the southern supercontinent of Gondwana, although there are fewer than 20 Australian dinosaurs, this is the fourth species described since 2015, including a sauropod, Savannasaurus, an Ankylosaurus, Kunbarrasaurus and another small Ornithopod , Diluvic cursor .

What is today a dry, dusty environment littered with bushy vegetation could not have been any different at the time when Weewarrasaurus lived there. In the middle of the Cretaceous, Lightning Ridge was a lush area of ​​lakes and waterways on the edge of the prehistoric Eromanga Sea.

At that time he was also 60 degrees south, much closer to the Antarctic Circle. Lightning Ridge would have been about as close to the South Pole as the Finnish capital Helsinki today at the North Pole. The area had a temperate climate that rarely dropped below 40 degrees Fahrenheit, but experienced long, dark winters with days when the sun rose only briefly above the horizon.

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"Fossils from the ridge help enlighten the faunas of the eastern Gondwanaland," which at that time covered perhaps a fifth of the world's land surface 96 to 100 million years ago, says paleontologist Ralph Molnar with the Museum of Northern Arizona Flagstaff.

When humans think about chalk dinosaurs, Western American species usually dominate the picture. But "the Tyrannosaurus Ceratopsian Hadrosaur Fauna" seems to be something special for North America and Asia, "says Molnar, who previously lived in the Queensland Museum, where he was involved in the discovery of Muttaburrasaurus in 1981. Australia

In contrast, the dinosaur fauna of the southern hemisphere had a completely different composition, and even between South America (then Western Gondwana) and Australia, the differences come into focus.

"A specific difference from South America is the abundance and the diversity of small ornithopods in Australia. "

An abundance of ornithopods

Fossil fragments show that there were up to three species of small ornithopods in Lightning Ridge, reports Bell's team in the newspaper, while four others from the state Victoria are known.

In North America, small ornithopods lived alongside larger horned Ceratopsian s and hadrosaurs who are "on the evolution ladder when it comes to chewing the vegetation," says Bell. Small ornithopods such as Thescelosaurus may have had difficulty moving here and have never been an essential feature of ecosystems. Triceratops and their relatives, however, never arrived in Australia together with the duckbill-less species.

"Here, small ornithopods had a free range to feed as much vegetation as they wanted in many different ways," says Bell.

"The new discoveries can help us to understand the relationships, possible migrations, and the relationship between the small bipedal herbivorous dinosaurs of South America, Antarctica, and Australia during the Cretaceous," says Penelope Cruzado-Caballero, an expert on herbivorous dinosaurs at the National University of Río Negro in Argentina.

While today's continents that made up Gondwana had already dispersed, their team in Antarctica found fossils of related ornithopods, and Argentina "tells us that during the Cretaceous, there were bridges that at least temporarily interconnected these continents "she says. "Did the South American fauna migrate through the Antarctic to Australia, where the Australian ornithopods originated? Or was it the other way around? "

New fossils can help fill these gaps in knowledge, and Bell and his team are now even working on a number of other opalescent specimens that could be termed new species in the coming years. 19659033]
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