page_title: Carnotaurus
section_title: Classification
hierarchical_section_title: Carnotaurus / Classification
caption_attribution_description: Forelimb of Carnotaurus (MACN-CH 894). Scale bar: 5 cm.
context_page_description: Carnotaurus is a genus of large theropod dinosaur that lived in South America during the Late Cretaceous period, between about 72 and 69.9 million years ago. The only species is Carnotaurus sastrei. Known from a single well-preserved skeleton, it is one of the best-understood theropods from the Southern Hemisphere. The skeleton, found in 1984, was uncovered in the Chubut Province of Argentina from rocks of the La Colonia Formation. Carnotaurus is a derived member of the Abelisauridae, a group of large theropods that occupied the large predatorial niche in the southern landmasses of Gondwana during the late Cretaceous. The phylogenetic relations of Carnotaurus are uncertain; it might have been closer to either Majungasaurus or Aucasaurus.
  Carnotaurus was a lightly built, bipedal predator, measuring 7.5 to 9 m in length and weighing at least 1.35 metric tons. As a theropod, Carnotaurus was highly specialized and distinctive. It had thick horns above the eyes, a feature unseen in all other carnivorous dinosaurs, and a very deep skull sitting on a muscular neck. Carnotaurus was further characterized by small, vestigial forelimbs and long, slender hindlimbs.
context_section_description: Carnotaurus is one of the best-understood genera of the Abelisauridae, a family of large theropods restricted to the ancient southern supercontinent Gondwana. Abelisaurids were the dominant predators in the Late Cretaceous of Gondwana, replacing the carcharodontosaurids and occupying the ecological niche filled by the tyrannosaurids in the northern continents. Several notable traits that evolved within this family, including shortening of the skull and arms as well as peculiarities in the cervical and caudal vertebrae, were more pronounced in Carnotaurus than in any other abelisaurid.
  Though relationships within the Abelisauridae are debated, Carnotaurus is consistently shown to be one of the most derived members of the family by cladistical analyses. Its nearest relative might have been either Aucasaurus or Majungasaurus; this ambiguity is largely due to the incompleteness of the Aucasaurus skull material. A recent review suggests that Carnotaurus was not closely related to either Aucasaurus or Majungasaurus, and instead proposed Ilokelesia as its sister taxon.
  Carnotaurus is eponymous for two subgroups of the Abelisauridae: the Carnotaurinae and the Carnotaurini. Paleontologists do not universally accept these groups. The Carnotaurinae was defined to include all derived abelisaurids with the exclusion of Abelisaurus, which is considered a basal member in most studies. However, a 2008 review suggested that Abelisaurus was a derived abelisaurid instead. Carnotaurini was proposed to name the clade formed by Carnotaurus and Aucasaurus; only those paleontologists who consider Aucasaurus as the nearest relative of Carnotaurus use this group.
  Below is a cladogram published by Canale and colleagues in 2009.
caption: Forelimb bones
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