Largest fully preserved dinosaur claw unearthed in Mongolia’s Gobi Desert

CALGARY

With distinctive two-fingered claws, the remains of a previously unknown species of dinosaur suggest it looked like a bizarre mix of sloth, giraffe and cult movie hero Edward Scissorhands, according to new research.

Paleontologists unearthed the fossil in Mongolia’s Gobi Desert, and the find is unique because the sheath of one of the digits is intact. Made of keratin (the same material as fingernails), the sheath reveals that the claw itself was much longer than the underlying bones. It is the largest claw of its kind found fully preserved in this way, researchers say.

“It’s close to a foot in size,” said paleontologist Darla Zelenitsky, an associate professor at the University of Calgary in Canada and coauthor of a study on the discovery published in the journal iScience. “This is by far the biggest claw preserved for a dinosaur that has that keratinous sheath on it.”

The dinosaur has been given the scientific name Duonychus tsogtbaatari, in honor of Mongolian paleontologist Khishigjav Tsogtbaatar. The genus name Duonychus means “two claws” in Greek.

Duonychus tsogtbaatari was part of an awkward-looking group of dinosaurs known as therizinosaurs, which were part of the theropod family that includes Tyrannosaurus rex. Therizinosaurs, however, were plant-eaters or omnivores — not apex predators.

The newly discovered dinosaur stood about three meters tall and would have weighed 260 kilograms. It likely used its curved claws to reach vegetation, and it could have grasped branches up to 10 centimeters in diameter, according to the study.

As well as two claws, the paleontologists also found fossilized parts of the prehistoric creature’s backbone, tail, hips, arms and legs. The fossil was discovered by staff at Mongolia’s Institute of Paleontology, part of the Mongolian Academy of Sciences, several years ago, Zelenitsky said.

Besides grasping, the two-fingered hands may have been used for display or as formidable weapons when needed, Zelenitsky said.

“They weren’t predators, but they could defend themselves with those claws. They were big and very sharp,” she said.

The best comparison for the distinctive digits among living animals would be the claws of a sloth, used for hanging onto tree branches, Zelenitsky added.