Open Paleo

Patagonykinae

Agnolín et al., 2012 Type genus Patagonykus

Its genera lived 93.9–66.0 million years ago Late Cretaceous
Late Cretaceous stages

Patagonykinae is a subfamily of large-bodied, plesiomorphic South American alvarezsaurids comprising Patagonykus and Bonapartenykus from the Late Cretaceous of Patagonia. It groups the biggest known alvarezsaurs, which retain comparatively robust proportions relative to the miniaturized Asian parvicursorines.

Under dispute

The phylogenetic position of Patagonykinae is contested. It is recovered within Alvarezsauridae by its naming analysis (Agnolín and colleagues, 2012), as the sister group of the remaining alvarezsaurids, and by the most recent comprehensive alvarezsaur analysis (Meso and colleagues, 2024), as the poorly supported sister of an Alvarezsaurus plus Achillesaurus clade. Other analyses instead recover Patagonykus and Bonapartenykus outside Alvarezsauridae as non-alvarezsaurid alvarezsauroids: Xu and colleagues (2018) place them as successive outgroups along the alvarezsaurian stem, while Hartman and colleagues (2019) group them with Bannykus and Xiyunykus as patagonykines, and the clade's composition varies between studies.

Diagnosis

  1. Large body size relative to other alvarezsaurids
  2. Longitudinal ridge on the lateral surface of the coracoid
  3. Strongly sculptured ventral half of the coracoid
  4. Medially deflected coracoid

Genera placed directly in Patagonykinae

  • Bonapartenykus Agnolín et al., 2012 Maastrichtian (72.2–66.0 Ma)Argentina
  • Patagonykus Novas, 1996 Turonian–Coniacian (93.9–85.7 Ma)Argentina

References

  1. Agnolín, F. L.; Powell, J. E.; Novas, F. E.; Kundrát, M. (2012). New alvarezsaurid (Dinosauria, Theropoda) from uppermost Cretaceous of north-western Patagonia with associated eggs. Cretaceous Research 35: 33-56. Elsevier BV. doi:10.1016/j.cretres.2011.11.014 agnolín2012a
  2. Hartman, S.; Mortimer, M.; Wahl, W. R.; Lomax, D. R.; Lippincott, J.; Lovelace, D. M. (2019). A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight. PeerJ 7: e7247. PeerJ. doi:10.7717/peerj.7247

    Recovered Patagonykus and Bonapartenykus outside Alvarezsauridae, joined by Xiyunykus and Bannykus as patagonykines, though cautioning this arrangement is not heavily favored.

    hartman2019a
  3. Xu, X.; Choiniere, J.; Tan, Q.; Benson, R. B. J.; Clark, J.; Sullivan, C.; Zhao, Q.; Han, F.; Ma, Q.; He, Y.; Wang, S.; Xing, H.; Tan, L. (2018). Two Early Cretaceous Fossils Document Transitional Stages in Alvarezsaurian Dinosaur Evolution. Current Biology 28(17): 2853-2860.e3. Elsevier BV. doi:10.1016/j.cub.2018.07.057

    Recovered Patagonykus and Bonapartenykus outside Alvarezsauridae as successive outgroups on the alvarezsaurian stem, with Achillesaurus sister to Alvarezsauridae.

    xu2018c
  4. Makovicky, P. J.; Mitchell, J. S.; Meso, J. G.; Gianechini, F. A.; Cerda, I.; Apesteguía, S. (2026). Argentine fossil rewrites evolutionary history of a baffling dinosaur clade. Nature. doi:10.1038/s41586-026-10194-3

    Alnashetri redescription; treats Patagonykus only as an anatomical comparator and assigns Patagonykinae no phylogenetic position.

    makovicky2026a
  5. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Treats Patagonykinae as the South American alvarezsaurid clade of Patagonykus and Bonapartenykus, noting the name has seldom been used since it was coined.

    jones2026c
  6. Meso, J. G.; Pol, D.; Chiappe, L.; Qin, Z.; Díaz-Martínez, I.; Gianechini, F.; Apesteguía, S.; Makovicky, P. J.; Pittman, M. (2024). Body size and evolutionary rate analyses reveal complex evolutionary history of Alvarezsauria. Cladistics 41(2): 135-155. Wiley. doi:10.1111/cla.12600

    Recovered Patagonykinae in its comprehensive alvarezsaur analysis.

    meso2024a