Open Paleo

Orkoraptor

Novas et al., 2008

From Aoniken 'Orr-Korr', the local name for the La Leona River near the fossil site, combined with Latin 'raptor' meaning 'thief'; translates as 'Toothed River thief'.

83.6–66.0 million years ago Campanian–Maastrichtian, Late Cretaceous
Late Cretaceous stages

Orkoraptor is a genus of medium-sized megaraptoran theropod dinosaur from the late Cretaceous Period of Argentina. It is known from incomplete fossil remains including parts of the skull, teeth, tail vertebrae, and a partial tibia. The specialized teeth resemble those of some maniraptoriform theropods, namely the deinonychosaurs and compsognathids. This and other anatomical features led the authors who described it (Novas, Ezcurra, and Lecuona) to suggest that it was a maniraptoran coelurosaur. However, subsequent studies found it to be a megaraptoran. Found in the Cerro Fortaleza Formation of Southern Patagonia, it is one of the southernmost carnivorous dinosaurs known from South America.

Diagnosis

  1. Teeth with unserrated and transversely wide mesial margins, lacking denticles on mesial margin
  2. Median depression flanked by two longitudinal and narrow furrows on lingual tooth surface (autapomorphy)
  3. Postorbital with wide jugal process and obtuse orbital margin devoid of suborbital flange
  4. Quadratojugal with short jugal process, lacking strong caudoventral projection
  5. Proximal caudal vertebrae with small pleurocoels on each side

Species

Orkoraptor burkei Novas et al., 2008

Type species

Named for Coleman Burke, an amateur paleontologist who supported the expedition that collected the original fossils.

Holotype
MPM-PV 3457 , Museo Padre Molina, Rio Gallegos
Material
Right postorbital, right quadratojugal, probable coronoid, eight isolated teeth, atlantal intercentrum and right neurapophysis, two proximal caudal vertebrae, proximal half of right tibia, eight fragmentary ribs, three incomplete chevrons
Horizon
Cerro Fortaleza Formation, Campanian–Maastrichtian, Late Cretaceous , 83.6–66.0 million years ago
Locality
Los Hornos Hill, Santa Cruz, Argentina

References

  1. Novas, F. E.; Ezcurra, M. D.; Lecuona, A. (2008). Orkoraptor burkei nov. gen. et sp., a large theropod from the Maastrichtian Pari Aike Formation, Southern Patagonia, Argentina. Cretaceous Research 29(3): 468-480. Elsevier BV. doi:10.1016/j.cretres.2008.01.001 novas2008b
  2. Aranciaga Rolando, A. M.; Motta, M. J.; Agnolín, F. L.; Manabe, M.; Tsuihiji, T.; Novas, F. E. (2022). A large Megaraptoridae (Theropoda: Coelurosauria) from Upper Cretaceous (Maastrichtian) of Patagonia, Argentina. Scientific Reports 12(1). Springer Science and Business Media LLC. doi:10.1038/s41598-022-09272-z aranciagarolando2022a