A new dinosaur species has been discovered in Mongolia, challenging previous assumptions about theropod evolution. This species, named Duonychus tsogtbaatari, stands out because it only has two clawed fingers, unlike most of its relatives in the therizinosaur family, which typically have three. Found in the Gobi Desert, this rare fossil is offering scientists fresh insights into how these ancient creatures evolved and utilized their large claws.
The discovery of Duonychus was detailed in a study published in iScience, and it has sparked significant interest among paleontologists. Therizinosaurs are usually known for their massive claws and are often associated with plant-eating, two-legged dinosaurs. However, the fact that Duonychus has only two claws instead of three raises intriguing questions about how this dinosaur adapted to its environment and why it evolved in such an unusual way.
A Two-Clawed Dinosaur?
Therizinosaurs have long been recognized for their three clawed fingers, but Duonychus breaks this pattern. Darla Zelenitsky, a paleontologist at the University of Calgary and one of the study authors, said:
“To find a specimen with only two fingers/claws was surprising as this was so out of the ordinary for this group of dinosaurs.”
The fossil was discovered in the Bayanshiree Formation of southern Mongolia, where the hands were exceptionally well-preserved. This allowed scientists to examine the dinosaur’s anatomy in detail, including its claws.
What makes this find particularly special, as noted in the study published in the journal iScience, is that the claws still had remnants of a keratinous sheath, similar to human fingernails. This suggests that these claws were incredibly sharp and could have been used for various tasks.
Why Did Duonychus Have Only Two Claws?
One major question raised by this discovery is how Duonychus used its two claws. Yoshitsugu Kobayashi, the study’s lead author, explained that the dinosaur likely used its claws to grab and pull vegetation towards its mouth in a “hook-and-pull” motion.
“Based on the shape of its well-preserved claw and how it curved, Duonychus was likely using its hands to grab onto branches and pull vegetation closer, kind of like how chameleons do today,” he added.
This feeding strategy might have been more effective for Duonychus, giving it access to food that other therizinosaurs, with their three claws, may have struggled to reach. However, Kobayashi also suggests that the claws might have had other uses, such as defense, courtship, or even play.
What Does This Find Say About Theropod Evolution?
Kobayashi explained that Duonychus is the fifth known case of a theropod group evolving to lose a third finger. While this change may seem minor, it provides crucial insights into how these dinosaurs adapted to their environment. Losing a claw could have been beneficial for feeding or other behaviors, and it also highlights how evolution can take unexpected turns.
“While more fossils would help confirm this, all signs point to Duonychus representing a true evolutionary shift, not just a fluke,” he stated. “It’s a remarkable find that reshapes our understanding of therizinosaurs and theropod evolution as a whole.”
To better understand the reasons behind this change, scientists are now seeking additional specimens to validate and confirm this evolutionary pattern.
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