Bonapartenykus (meaning "Bonaparte's claw", named after José Bonaparte) is a genus of alvarezsaurid theropod dinosaurs known from the Late Cretaceous (Campanian/Maastrichtian stage) Allen Formation of northwestern Patagonia, Argentina. The type species is B. ultimus. An adult female of B. ultimus has been discovered with two eggs that may have still been inside its oviducts, although some evidence suggests that the eggs may have been incubated in a nest. The size of the adult female has been estimated as at least 8.5 feet (2.6 m), and the weight of Bonapartenykus has been estimated as 100 pounds (45 kg). Its diet probably consisted of insects. Paleontologist Fernando Novas compared its bones to those of the ñandú, a modern-day Patagonian flightless bird.