Fossils unearthed during construction of a water pipeline in the Gobi Desert of Mongolia have revealed one of the oddest members of a rather strange group of dinosaurs, a creature whose two-fingered hands sport a pair of menacing curved claws.

Paleontologists unearthed the fossil in Mongolia’s Gobi Desert, and the find is unique because of a sheath preserved on one of the digits, which reveals the claw’s true length.

The species, named Duonychus tsogtbaatari, belongs to a group of two-legged dinosaurs called therizinosaurs that lived in central and eastern Asia as well as in western North America during the Cretaceous period around 90 million years ago, researchers say.