Animals that Start with G - Listed With Pictures, Facts
Giant Ancient Lizard Covered In Thick Armor And Spikes Found: 'Bizarre'
A giant ancient lizard covered in thick armor and spikes has been discovered by scientists in Australia.
The turtle-like creature is "one of the most bizarre lizards found in recent times," said the authors of a study published in the journal Proceedings of the Royal Society B.
The now-extinct species, which forms part of the skink family, lived in the Pleistocene, the geological epoch that lasted from around 2.58 million to 11,700 years ago.
Skinks, a group of lizards that are found all over the world, are commonly recognized for their shiny, overlapping scales. There are more than 1,700 known species of skink today.
An artist's reconstruction shows a pair of Tiliqua frangens, with a small garden skink measuring 4 inches long in the corner for scale. The new species is by far the largest skink recorded to date. Katrina KennyMost skinks weigh less than 2 grams (0.07 ounces) and measure less than 10 centimeters (3.9 inches) in length.
But the newly discovered species is by far the largest skink recorded to date. In fact, it would have been more than a thousand times heavier than a typical skink, weighing roughly 2.4 kilograms, or 5.2 pounds, the researchers said.
The "gigantic" skink was at least 60 centimeters (2 feet) in length, whereas the longest living skinks today reach only around 35 centimeters (1.1 feet) when measuring between the nose and the vent at the start of the tail.
The new species, named Tiliqua frangens, most closely resembles Australia's shingleback lizards, a species of blue-tongued skink. But T. Frangens was more than twice as long and heavy as any of the largest living skinks today.
"The body size is huge compared to any other skink that we've ever known," Kailah Thorn, an author of the study who is affiliated with the Western Australian Museum, told Newsweek.
The fossils documented in the study show that the wide, heavy-set body of this creature was completely covered in "extremely thick, spikey armor," the authors said.
"The fossils preserve bones from within [the animal's] scales that acted as an external armor plating, and these bones have spikes on them," Thorn said.
She continued: "With the heavy armor plating, it's most likely that they foraged for plants out in the open during the day, much like living shingleback lizards in Australia and terrestrial tortoises in Africa and North America now. We can tell from the short and stocky limb bones that they moved slowly and had less maneuverability."
Compared with other groups, the fossil record of lizards and snakes has been poorly documented, even though there are more species of these animals than any other order of land vertebrates.
The identification of T. Frangens as a new species, by contrast, was based on the fossils of many individuals, spanning babies to adults. As a result, the study's authors have been able to learn a lot about the creature's growth and development, ecology and evolutionary relationships.
The species had been described on two separate previous occasions as two different species. Each of those descriptions was based on a single bone, and the scientists involved could not match them to the one animal. So it was named twice—Aethesia frangens and Tiliqua laticephala.
But beginning in 2016, excavations conducted by the study's authors at the Wellington Caves in New South Wales, Australia—as well as investigations of museum collections—unearthed new fossil materials that enabled the team to re-describe T. Frangens as a single new species.
"Now that we have so many more pieces, we know that they all fit together and represent one very unique animal," Thorn said.
The researchers found multiple pieces of this giant skink during the cave excavations. They also uncovered fossils belonging to the same species that were already stored in various museum collections but had not been described until now.
"The fossils are different pieces of the lizard's skeleton," Thorn said. "A lizard skull naturally breaks into multiple pieces, which makes them very difficult to reconstruct. All the material recovered from the new dig, as well as what I managed to find from the Queensland Museum, Australian Museum and Melbourne Museum paleontology collections, together represent most of the skull and some of the limbs and body of this species."
Given the number of different bones that the researchers found, the study's authors said that T. Frangens is now the most completely known Australian fossil lizard.
"We can now recognize more parts of this animal than any other Australian fossil lizard," Thorn said.
The researchers have most of the head, the humerus (upper arm), the tibia (lower leg) and a few important back bones (from the neck and between the hips), she said, as well as chunks of the armor plating preserved.
"We also have bones from young individuals, so we can see how big these animals were when they were born—blue-tongues give birth to live young, they don't lay eggs—and how they changed shape as they grew," Thorn said.
The oldest T. Frangens fossils that the researchers documented could be up to 2 million years old, she said. The youngest ones, meanwhile, have been dated to around 47,000 years before the present.
"This animal went extinct at the same time, and possibly for similar reasons, as the other Australian Pleistocene megafauna," Thorn said.
Looking at the palaeoclimate record, as well as examining other well-known fossil species from the same excavations, can yield information about the area in which these animals were living, according to Thorn.
"These lizards most likely lived in a temperate open woodland with patches of bluebush and saltbush plants—similar to modern shingleback habitat," she said.
The new findings highlight the fascinating ancient megafauna that once called this part of southeastern Australia home.
"Wellington Caves was the first site that Europeans uncovered megafauna fossils over 100 years ago, and we are still finding new giant fossil species there now," Thorn said. "There are other giant skink fossils in Australia, but we know very little about them because very few people work on fossil lizards here."
Extinct Lizard Was A Bizarrely Supersized Version Of Modern Skinks
Artist's impression of the extinct skink Tiliqua frangens. In the bottom right, a typical modern skink is shown for comparison
Kailah Thorn, Western Australian Museum
A giant skink with spiky armour and powerful jaws roamed inland Australia until about 47,000 years ago, according to newly discovered fossils.
In 2009 and 2013, scientists described two mysterious fossils – part of a jaw and skull – found in Wellington caves in New South Wales. They looked like they belonged to skinks – a type of lizard – but were unusually large.
Now, a more recent excavation at the same site has unearthed dozens of similar fossils. An analysis led by Kailah Thorn at the Western Australian Museum in Perth has revealed that they all belong to the same extinct species – a skink called Tiliqua frangens – that was about 1000 times heavier than typical skinks alive today.
The giant skink's closest living relative is Tiliqua rugosa, also known as the shingleback skink, which is found in dry, inland areas of New South Wales and other parts of southern Australia.
By comparing the two species' body measurements, Thorn and her colleagues estimated that the extinct skink would have weighed about 2.3 kilograms. Most living skinks only weigh about 2 grams, with the heaviest, the shingleback, reaching 1 kilogram.
The excavation uncovered a range of fossils of the giant skink aged 47,000 years and older, including teeth and parts of its skull, bony armour, spine and leg bones.
These showed that it had a deep, broad skull, along with powerful jaws and a coat of thick, spiky armour.
It probably wasn't very fast because it had short, squat legs, but this wouldn't have mattered because its armour would have provided protection from predators, says Thorn.
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The shape of its teeth suggests that, like modern-day shinglebacks, it mostly ate plants. It may have needed strong jaws because it "ate something tough, like tough plant fibre or maybe a tough fruit or nut that dried out in summer", she says.
Thorn and her colleagues have since found other fossils of the species sitting unidentified in old museum collections. These show that it was distributed across inland New South Wales and south-east Queensland, places that were likely to have been dry and open.
The skink lived at the same time as other giant creatures in Australia – including giant kangaroos, wombats and "marsupial lions" – collectively known as megafauna. The skink and other megafauna are thought to have gone extinct more than 40,000 years ago due to the arrival of people or climate change.
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