Open Paleo

Achillobator

Perle et al., 1999 uh-KIL-uh-BAY-tor /əˌkɪləˈbeɪtɔːr/

Named after Achilles, the Greek hero, combined with Mongolian 'bator' meaning 'hero'; meaning 'Achilles hero'

100.5–83.6 million years ago Cenomanian–Santonian, Late Cretaceous
Late Cretaceous stages

Achillobator is a genus of large dromaeosaurid theropod dinosaur that lived during the Late Cretaceous period about 96 million to 89 million years ago in what is now the Bayanshiree Formation of Mongolia. The genus is currently monotypic, only including the type species A. giganticus. The first remains were found in 1989 during a Mongolian-Russian field expedition and later described in 1999. Remains at the type locality of Achillobator may represent additional specimens. It represents the first and largest dromaeosaurid known from the Bayanshiree Formation.

Under dispute

Achillobator is most often recovered as a large-bodied dromaeosaurine, close to Utahraptor (Turner and colleagues, 2012; Cau and colleagues, 2017; Napoli and colleagues, 2021), though one analysis on the matrix of Currie and Evans recovers it as a velociraptorine (Powers and colleagues, 2020). Burnham and colleagues (2000) suspected the holotype is a chimera, but Turner and colleagues (2012) found the elements articulated and alike in preservation, and assigned them to one individual. It is placed in Dromaeosaurinae following most analyses.

Species

Achillobator giganticus Perle et al., 1999

Type species

From Latin 'giganticus' meaning 'gigantic', reflecting that Achillobator is one of the largest known dromaeosaurids.

Holotype
MNUFR 15 , Mongolian National University
Horizon
Bayanshiree Formation, Cenomanian–Santonian, Late Cretaceous , 100.5–83.6 million years ago The age of the containing rock unit; no finer age has been published.
Locality
Burkhant, Dornogovi, Mongolia

References

  1. Perle, A.; Norell, M. A.; Clark, J. M. (1999). A new maniraptoran theropod-Achillobator giganticus (Dromaeosauridae)-from the Upper Cretaceous of Burkhant, Mongolia. Contributions of the Department of Geology, National University of Mongolia 101: 1-105. perle1999a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026c
  3. Turner, A. H.; Makovicky, P. J.; Norell, M. A. (2012). A Review of Dromaeosaurid Systematics and Paravian Phylogeny. Bulletin of the American Museum of Natural History 371: 1-206. doi:10.1206/748.1

    Dromaeosaurid systematics review recovering Achillobator as a large-bodied dromaeosaurine.

    turner2012a
  4. Cau, A.; Beyrand, V.; Voeten, D. F. A. E.; Fernandez, V.; Tafforeau, P.; Stein, K.; Barsbold, R.; Tsogtbaatar, K.; Currie, P. J.; Godefroit, P. (2017). Synchrotron scanning reveals amphibious ecomorphology in a new clade of bird-like dinosaurs. Nature 552(7685): 395-399. Springer Science and Business Media LLC. doi:10.1038/nature24679

    New taxon description recovering Achillobator within Dromaeosaurinae alongside amphibious relatives.

    cau2017a
  5. Napoli, J. G.; Ruebenstahl, A. A.; Bhullar, B. A. S.; Turner, A. H.; Norell, M. A. (2021). A New Dromaeosaurid (Dinosauria: Coelurosauria) from Khulsan, Central Mongolia. American Museum Novitates 2021(3982). American Museum of Natural History (BioOne sponsored). doi:10.1206/3982.1

    Recovered Achillobator as a eudromaeosaur outside a narrowly defined Velociraptorinae.

    napoli2021a
  6. Powers, M. J.; Sullivan, C.; Currie, P. J. (2020). Re-examining ratio based premaxillary and maxillary characters in Eudromaeosauria (Dinosauria: Theropoda): Divergent trends in snout morphology between Asian and North American taxa. Palaeogeography, Palaeoclimatology, Palaeoecology 547: 109704. doi:10.1016/j.palaeo.2020.109704

    Compared premaxillary and maxillary snout morphology among eudromaeosaurs including Achillobator

    powers2020a
  7. Burnham, D. A.; Derstler, K. L.; Currie, P. J.; Bakker, R. T.; Zhou, Z.; Ostrom, J. H. (2000). Remarkable new birdlike dinosaur (Theropoda: Maniraptora) from the Upper Cretaceous of Montana. University of Kansas Paleontological Contributions 13: 1-14. doi:10.17161/pcns.1808.3761

    Suspected the Achillobator holotype is a mixture of bones from more than one species.

    burnham2000a