Mononychus olecranus Perle et al., 1993 (preoccupied generic name) Mononykus (/məˈnɒnɪkəs/ mə-NON-ik-əs, sometimes /ˌmɒnoʊˈnaɪkəs/ MON-oh-NY-kəs; meaning "one claw") is a genus of alvarezsaurid dinosaur that lived during the Late Cretaceous in what is now Asia on the Nemegt Formation, about 70 million years ago.

It was lightly built with long, thin legs and highly reduced and specialized forelimbs that were likely used for foraging termite mounds or other insect colonies.

[12][13] For this reason it is possible Mononykus also had a facial disc of specialized feathers, similar to extant owls, that served to catch sound and direct it to the ears.

The purpose of these highly specialized arms is still a mystery, but some scientists have suggested they were used to break open termite mounds (like modern anteaters), and therefore it is possible that they fed primarily on insects.

[14] In a 2001 study conducted by Bruce Rothschild and other paleontologists, 15 foot bones referred to Mononykus were examined for signs of stress fracture, but none were found.