Bonapartenykus is an extinct genus of alvarezsauroid dinosaur that lived during the Late Cretaceous (Campanian–Maastrichtian) of what is now the Allen Formation of the Río Negro Province, Argentina. The genus contains a single species, Bonapartenykus ultimus, known from a partially articulated, incomplete skeleton that was found in close association to two incomplete eggs and several clusters of eggshells belonging to the oogenus Arriagadoolithus. Bonapartenykus was named in 2012. It has an estimated length of 2.5–3.3 m (8.2–10.8 ft) and weight of 43–72 kg (95–159 lb), making it the largest member of the clade Alvarezsauroidea. Additional skeletons referrable to this genus have subsequently been described.
F. L. Agnolin, J. E. Powell, and F. E. Novas, M. Kundrát. 2012. New alvarezsaurid (Dinosauria, Theropoda) from uppermost Cretaceous of north-western Patagonia with associated eggs. Cretaceous Research 35(1):33-56
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Bibliography (2)
J. G. Meso, J. N. Choiniere, and M. A. Baiano, S. L. Brusatte, J. I. Canale, L. Salgado, D. Pol, M. Pittman. 2025. New information on Bonapartenykus (Alvarezsauridae: Theropoda) from the Allen Formation (middle Campanian-lower Maastrichtian) of Río Negro Province, Patagonia, Argentina clarifies the Patagonykinae body plan. PLOS ONE 20(1):e0308366
DOI ↗
F. L. Agnolin, J. E. Powell, and F. E. Novas, M. Kundrát. 2012. New alvarezsaurid (Dinosauria, Theropoda) from uppermost Cretaceous of north-western Patagonia with associated eggs. Cretaceous Research 35(1):33-56
DOI ↗