Researchers have welcomed the finding of a massive marine reptile's skeleton in Australia that is 100 million years old as a significant discovery that could reveal important information about prehistoric life.

Three amateur paleontologists discovered the remains of the 6-meter (19-foot) tall juvenile long-necked plesiosaur, commonly known as an elasmosaur, in August 2022 on a cattle station in the western Queensland outback.

Espen Knutsen, senior curator of palaeontology at the Queensland Museum, compared the find to the 1799 rediscovery of the Rosetta Stone, an ancient Egyptian granite block that assisted researchers in deciphering hieroglyphics.

"We have never found a body and a head together and this could hold the key to future research in this field," Knutsen said in a statement that confirmed the discovery on Wednesday. He added that it could give paleontologists more insight into the origins, evolution, and ecology of the cretaceous period in the area.

"Because these plesiosaurs were two-thirds neck, the head would often be separated from the body after death, which makes it very hard to find a fossil preserving both together," he said.

The "Rock Chicks"—Cassandra Prince, Cynthia Prince, and colleague fossil hunter Sally, who only goes by her first name—are a group of amateur paleontologists who made the discovery.

Around 150 million years ago, the Eromanga Sea, which had waters that were 50 meters deep, covered a major portion of rural Australia and was home to elasmosaurs, which grew to a length of 8 to 10 meters.

When an elasmosaur died, according to Knutsen, its rotting body would expand with gas and rise to the water's surface. Additionally, the head would frequently break off when predators scavenged the cadaver, making full-body discoveries uncommon.

He continued by saying that the most recent discovery, a young specimen, will clarify how the body structure of elasmosaurs altered from infancy to adulthood.

We're going to look at the chemistry of its teeth, and that can tell us a lot about its ecology in terms of habitat, whether it was traveling throughout its life or whether it was sort of sticking in the same habitat, as well as its food, he said.

Plesiosaurs and ichthyosaurs, two extinct sea reptiles that lived in the same time period as dinosaurs, are not considered to be dinosaurs. Plesiosaurs descended from land-dwelling predecessors who were forced to occasionally rise for air since they lacked gills. How long they could submerge is still a mystery.

It's the most significant prehistoric discovery to have recently been made in Australia.

In June 2021, experts determined that the Queensland fossilized skeleton found in 2007 represented the largest dinosaur ever found in Australia. The dinosaur, known as "Cooper," was the length of a basketball court and stood about two floors tall.

Two months later, researchers learned that 105 million years ago, a species of flying "dragon" flew across Australia. Researchers referred to the pterosaur as a "fearsome beast" that dined on young dinosaurs.