Patagonykus is a genus of theropod dinosaur from the Upper Cretaceous of Argentina. This alvarezsaur was discovered in exposures of the Portezuelo Member (Turonian-Coniacian) of the Rio Neuquen Formation in the Neuquen Province of Argentina. The holotype consists of an incomplete but well-preserved skeleton, lacking a skull, but including many vertebrae, the coracoids, a partial forelimb, pelvic girdle, and hindlimbs. Patagonykus ("Patagonian claw") has been classed with the Alvarezsauridae, a family which includes such taxa as the Mongolian Mononykus and the Argentinian Alvarezsaurus. Patagonykus is estimated to have been approximately two meters in length.