Open Paleo

Abelisaurus

Bonaparte & Novas, 1985 ah-BEL-i-SAWR-us /əˌbɛlɪˈsɔːrəs/

Named for Roberto Abel, discoverer of the type specimen and former director of the provincial Museum of Cipolletti, combined with Greek 'sauros' meaning 'lizard'.

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Abelisaurus is a genus of predatory abelisaurid theropod dinosaur which lived during the Late Cretaceous Period (Campanian) of what is now South America. It was a bipedal carnivore that probably reached about 7.4 meters (24 ft 3 in) in length, although this is uncertain as it is known from only one partial skull.

Under dispute

The position of Abelisaurus is unresolved and it behaves as a wildcard taxon. It has been recovered as an unstable wildcard among the derived abelisaurids (Carrano and Sampson, 2008), within Furileusauria as a relative of Carnotaurus and Aucasaurus (Filippi and colleagues, 2016; Gianechini and colleagues, 2021), within Carnotaurini (Tortosa and colleagues, 2014), and within Majungasaurinae (Pol and colleagues, 2024).

Diagnosis

  1. Antorbital fenestra proportionally larger than in Tyrannosauridae; small accessory antorbital fenestra on anterior border of antorbital fossa
  2. Interorbital region wider than other carnosaurs with lateral contact external to lacrimal and postorbital forming orbital overhang
  3. Orbital fenestra very tall with low jugal; orbit nearly closed ventrally
  4. Squamosal projects nearly horizontally backward with quadratojugal process directed ventrally rather than anteriorly
  5. Quadrate notably longer than in Tyrannosauridae; transversely wide distally
  6. Lower temporal fenestra very wide in both directions, notably larger than in Tyrannosauridae

Species

Abelisaurus comahuensis Bonaparte & Novas, 1985

Type species

Named for the Comahue region of Argentina, where the fossil was found.

Holotype
MPCA-PV 11098 , Museo provincial de Cipolletti "Carlos Ameghino"
Material
Large part of skull lacking right maxilla, jugal, quadratojugal, and squamosal; major part of palate absent. 85 cm maximal length.
Horizon
lower Allen Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Lago Pellegrini stone quarries, Río Negro, Argentina Where the holotype came from is unsettled. Bonaparte and Novas (1985) placed it in the lower Allen Formation at the Lago Pellegrini quarries. Heredia and Salgado (1999) reassigned the Pellegrini dinosaur beds, and Leanza and colleagues (2004) followed them, which is where the Anacleto attribution comes from. Gianechini and colleagues (2015) return the specimen to the Allen Formation and go further, reporting from local testimony that it came from the Sr. Fernandez field near Salitral Moreno rather than Pellegrini at all, while cautioning that "no witnesses are alive and no field notes were taken". Aranciaga Rolando and colleagues (2020) note a further referral to the lower member of the Allen Formation and treat the position as uncertain pending published evidence.

References

  1. Bonaparte, J. F. (1984). I dinosauri dell'Argentina [. Sulle Orme dei Dinosauri 125-143. Erizzo Editrice, Esplorazioni e Ricerche. bonaparte1984a
  2. Bonaparte, J. F.; Novas, F. E. (1985). Abelisaurus comahuensis, n.g., n.sp., Carnosauria del Crétacico Tardio de Patagonia [Abelisaurus comahuensis, n.g., n.sp., Carnosauria from the Late Cretaceous of Patagonia]. Ameghiniana 21: 259-265.

    In Spanish.

    bonaparte1985b
  3. Heredia, S.; Salgado, L. (1999). Posición estratigráfica de los estratos supracretácicos portadores de dinosaurios en el Lago Pellegrini, Patagonia septentrional, Argentina. Ameghiniana 36(2): 229-234.

    Reassigned the Lago Pellegrini dinosaur beds, the origin of the Anacleto attribution. In Spanish.

    heredia1999a
  4. Leanza, H. A.; Apesteguía, S.; Novas, F. E.; de la Fuente, M. S. (2004). Cretaceous terrestrial beds from the Neuquén Basin (Argentina) and their tetrapod assemblages. Cretaceous Research 25(1): 61-87. Elsevier BV.

    Follows Heredia and Salgado in placing the holotype in the Anacleto Formation.

    leanza2004a
  5. Gianechini, F. A.; Apesteguía, S.; Landini, W.; Finotti, F.; Juárez Valieri, R. D.; Zandonai, F. (2015). New abelisaurid remains from the Anacleto Formation (Upper Cretaceous), Patagonia, Argentina. Cretaceous Research 54: 1-16. Elsevier BV.

    Returns the holotype to the Allen Formation and questions the Lago Pellegrini provenance.

    gianechini2015a
  6. Aranciaga Rolando, M.; Cerroni, M. A.; García Marsà, J. A.; Agnolín, F. L.; Motta, M. J.; Rozadilla, S.; Brissón Egli, F.; Novas, F. E. (2020). A new medium-sized abelisaurid (Theropoda, Dinosauria) from the late cretaceous (Maastrichtian) Allen Formation of Northern Patagonia, Argentina. Journal of South American Earth Sciences 105. Elsevier BV. doi:10.1016/j.jsames.2020.102915

    Reviews the competing referrals and treats the stratigraphic position as uncertain.

    aranciagarolando2020a
  7. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Theropods. Princeton University Press.

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

    jones2026c
  8. Carrano, M. T.; Sampson, S. D. (2008). The Phylogeny of Ceratosauria (Dinosauria: Theropoda). Journal of Systematic Palaeontology 6(2): 183-236. doi:10.1017/S1477201907002246

    Recovered Abelisaurus as an unstable wildcard among the derived abelisaurids, not in a basal position, in their Ceratosauria phylogeny

    carrano2008a
  9. Filippi, L. S.; Méndez, A. H.; Juárez Valieri, R. D.; Garrido, A. C. (2016). A new brachyrostran with hypertrophied axial structures reveals an unexpected radiation of latest Cretaceous abelisaurids. Cretaceous Research 61: 209-219. Elsevier BV. doi:10.1016/j.cretres.2015.12.018

    Recovered Abelisaurus within Furileusauria, close to Carnotaurus and Aucasaurus.

    filippi2016a
  10. Tortosa, T.; Buffetaut, E.; Vialle, N.; Dutour, Y.; Turini, E.; Cheylan, G. (2014). A new abelisaurid dinosaur from the Late Cretaceous of southern France: Palaeobiogeographical implications. Annales de Paléontologie 100(1): 63-86. Elsevier BV. doi:10.1016/j.annpal.2013.10.003

    Recovered Abelisaurus within Carnotaurini, as sister to Aucasaurus.

    tortosa2014a
  11. Pol, D.; Baiano, M. A.; Černý, D.; Novas, F. E.; Cerda, I. A.; Pittman, M. (2024). A new abelisaurid dinosaur from the end Cretaceous of Patagonia and evolutionary rates among the Ceratosauria. Cladistics 40(3): 307-356. Wiley. doi:10.1111/cla.12583

    Recovered Abelisaurus within Majungasaurinae (weakly supported).

    pol2024a
  12. Gianechini, F. A.; Méndez, A. H.; Filippi, L. S.; Paulina-Carabajal, A.; Juárez Valieri, R. D.; Garrido, A. C. (2021). A new furileusaurian abelisaurid from La Invernada (Upper Cretaceous, Santonian, Bajo de la Carpa Formation), northern Patagonia, Argentina. Journal of Vertebrate Paleontology 40(6): e1877151. Informa UK Limited. doi:10.1080/02724634.2020.1877151

    Recovered Abelisaurus nested within Furileusauria, grouped with Carnotaurus and Aucasaurus.

    gianechini2021a