A rare fossil unearthed in Mongolia's Gobi Desert has led to the identification of a new dinosaur species, Duonychus tsogtbaatari, belonging to the Therizinosaurus family - a group of plant-eating dinosaurs that once evolved from meat-eating ancestors.
The species, discovered by an international team of scientists, is notable for its unusually large, curved claws - each nearly 30 centimeters (about one foot) in length - and a rare keratin sheath that once covered them. This marks the first known instance of such a sheath found in a Therizinosaur.
Weighing an estimated 260 kilograms, Duonychus tsogtbaatari was a medium-sized, bipedal dinosaur. Researchers believe its enormous claws were used for multiple purposes, including feeding on vegetation, digging, self-defense, and even mating displays.
The fossil was discovered in the Bayanshiree Formation, a geological layer dating back between 100 and 66 million years ago - near the end of the Cretaceous period. The Cretaceous is known as the final chapter in the Age of Dinosaurs, preceding the mass extinction event that wiped out nearly three-quarters of life on Earth.
Therizinosaurs represent an unusual offshoot of the theropod clade, which traditionally includes fast-moving, carnivorous species like Tyrannosaurus rex. Unlike their theropod cousins, Therizinosaurs evolved long necks, bulky bodies, large claws, and feathered coats, with many species inhabiting regions of present-day Asia and North America.
The presence of only two fingers on Duonychus may recall the structure of the T. rex, but scientists emphasize this trait emerged independently and was the result of convergent evolution rather than shared ancestry.
The Gobi Desert
The Gobi Desert has long been a fertile ground for paleontological discovery. Recognized by UNESCO as the largest dinosaur fossil repository in the world, it continues to yield significant finds that reshape scientists’ understanding of prehistoric life.
Dinosaurs first appeared around 230 million years ago during the Triassic period and rose to dominance throughout the Jurassic. The Cretaceous period, which spanned from 145 to 66 million years ago, saw the emergence of advanced species such as Velociraptor, Triceratops, and T. rex.
Dinosaurs once ruled all continents, including regions that were far warmer and wetter than today. They ranged from swift predators to massive herbivores, some stretching dozens of meters in length and weighing many tons.
The age of the dinosaurs came to an end approximately 66 million years ago when a massive asteroid struck near the Yucatán Peninsula. The resulting climatic upheaval led to a global extinction event, wiping out most species, including all non-avian dinosaurs.
Fossil discoveries continue to shed light on this ancient era. The Duonychus specimen joins a growing list of recent finds that enhance the scientific community’s understanding of dinosaur evolution, behavior, and eventual extinction.