Open Paleo

Saurornitholestinae

Longrich & Currie, 2009 Type genus Saurornitholestes

Its genera lived 83.6–66.0 million years ago Late Cretaceous
Late Cretaceous stages

Saurornitholestinae is a subfamily of eudromaeosaurian dromaeosaurid dinosaurs known only from the Late Cretaceous of western North America. Its members are medium-sized predators generally distinguished by their comparatively short snouts, and the group is typically taken to include Atrociraptor, Bambiraptor, and Saurornitholestes. It is most often recovered as the sister group to a clade uniting the dromaeosaurines and velociraptorines. Its exact position is contested, however: some analyses instead find its proposed members to be the earliest-diverging branch of the eudromaeosaurs rather than a clade of their own.

Under dispute

Saurornitholestinae is not universally recovered. It is supported as a monophyletic North American subfamily (Saurornitholestes, Atrociraptor, and sometimes Acheroraptor and Bambiraptor) by Longrich and Currie (2009), Currie and Evans (2019), and Powers and colleagues (2022). Pei and colleagues (2020) do not recover it, instead placing Saurornitholestes and Bambiraptor as the earliest-diverging eudromaeosaurs, with their relative order varying between equal and implied weighting. It is retained following the recent cranial-anatomy studies that support it.

Diagnosis

  1. Short, deep snout relative to velociraptorines
  2. Enlarged, strongly recurved anterior maxillary and dentary teeth
  3. Second premaxillary tooth enlarged and flattened with ridged enamel

Genera placed directly in Saurornitholestinae

  • Atrociraptor Currie & Varricchio, 2004 Campanian–Maastrichtian (83.6–66.0 Ma)Canadaunder dispute
  • Saurornitholestes Sues, 1978 Campanian (83.6–72.2 Ma)Canada

References

  1. Longrich, N. R.; Currie, P. J. (2009). A microraptorine (Dinosauria-Dromaeosauridae) from the Late Cretaceous of North America. Proceedings of the National Academy of Sciences 106(13): 5002-5007. Proceedings of the National Academy of Sciences. doi:10.1073/pnas.0811664106

    Coined Saurornitholestinae for Saurornitholestes, Atrociraptor and Bambiraptor, and Eudromaeosauria for the larger clade.

    longrich2009a
  2. Pei, R.; Pittman, M.; Goloboff, P. A.; Dececchi, T. A.; Habib, M. B.; Kaye, T. G.; Larsson, H. C. E.; Norell, M. A.; Brusatte, S. L.; Xu, X. (2020). Potential for Powered Flight Neared by Most Close Avialan Relatives, but Few Crossed Its Thresholds. Current Biology 30(20): 4033-4046.e8. Elsevier BV. doi:10.1016/j.cub.2020.06.105

    Did not recover Saurornitholestinae; placed Saurornitholestes and Bambiraptor as the earliest-diverging eudromaeosaurs, their order varying with weighting scheme.

    pei2020a
  3. Powers, M. J.; Fabbri, M.; Doschak, M. R.; Bhullar, B. A. S.; Evans, D. C.; Norell, M. A.; Currie, P. J. (2022). A new hypothesis of eudromaeosaurian evolution: CT scans assist in testing and constructing morphological characters. Journal of Vertebrate Paleontology 41(5). doi:10.1080/02724634.2021.2010087

    Used CT scans to test eudromaeosaurian evolution, supporting a monophyletic North American saurornitholestine subfamily

    powers2022a
  4. Currie, P. J.; Evans, D. C. (2019). Cranial Anatomy of New Specimens of Saurornitholestes langstoni (Dinosauria, Theropoda, Dromaeosauridae) from the Dinosaur Park Formation (Campanian) of Alberta. The Anatomical Record 303(4): 691-715. Wiley. doi:10.1002/ar.24241

    Supported Saurornitholestinae as a monophyletic North American subfamily.

    currie2019a