Carnotaurus

Carnotaurus was a predatory dinosaur. It lived 70 million years ago in the Cretaceous period. It was a large theropod which lived in South America. Although there is only one 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.

Carnotaurus is a member of the Abelisauridae, a group of large theropods. They lived only in the ancient southern supercontinent Gondwana. They were the dominant predators of the later Cretaceous of Gondwana. They occupied the ecological niche filled by the tyrannosaurids in the northern continents.Candeiro, Carlos Roberto dos Anjos & Martinelli, Agustín Guillermo. 2005. Abelisauroidea and Carchardontosauridae (Theropoda, Dinosauria) in the Cretaceous of South America. Paleogeographical and geocronological implications. Uberlândia Sociedade de Naturaleza 17 (33): 5–19. 

 Description 
Carnotaurus was a lightly built, bipedal predator, about 4.6 m (16 ft) tall,  in length and weighing . As a theropod, Carnotaurus was highly specialized and distinctive. It had thick horns above the eyes, a feature not seen in other carnivorous dinosaurs, and a very deep skull sitting on a muscular neck. Also, it had small, vestigial forelimbs, smaller even than those of Tyrannosaurus.

The remains include skin impressions showing a mosaic of small, non-overlapping scales about 5 mm in diameter. The mosaic was interrupted by large bumps that lined the sides of the animal, and there are no hints of feathers.Carrano, Matthew T. & Sampson, Scott D. 2008. The phylogeny of Ceratosauria (Dinosauria: Theropoda). Journal of Systematic Palaeontology 6 (2): 183–236. Bonaparte, José F. et al 1990. Carnotaurus sastrei Bonaparte, the horned, lightly built carnosaur from the Middle Cretaceous of Patagonia. Contributions in Science (Natural History Museum of Los Angeles County) 416.  

The distinctive horns and muscular neck may have been used in fighting rivals of its own species. Rivals may have fought with quick head blows, by slow pushes with the upper sides of their skulls, or by ramming each other head-on, using their horns as shock absorbers. The feeding habits of Carnotaurus remain unclear. Some studies suggest the animal was able to hunt down very large prey such as sauropods, while other studies find it preyed mainly on relatively small animals. Carnotaurus was well adapted for running and was possibly one of the fastest large theropods.

 Palaeoecology 
The animal lived in an environment of estuaries, tidal flats or coastal plains.Pascual, Rosendo et al 2000. A highly derived docodont from the Patagonian late Cretaceous: evolutionary implications for Gondwanan mammals. Geodiversitas 22 (3): 395, 399–400. The climate would have been seasonal with both dry and humid periods. The most common vertebrates collected include  lungfish, turtles, crocodiles, plesiosaurs, dinosaurs, lizards, snakes and mammals. Turtles are represented by at least five taxa. In 2011, the discovery of a new enantiornithine bird from the La Colonia Formation was announced.Lawver, Daniel R. et al 2011. A new enantiornithine bird from the Upper Cretaceous La Colonia Formation of Patagonia, Argentina. Annals of Carnegie Museum 80 (1): 35–42. 

 Media 
It appears in the movie Dinosaur (2000), when two Carnotaurus were killing other species of Iguanodon, Parasaurolophus, Pachyrhinosaurus or Stygimoloch. And in Jurassic World 2: Fallen Kingdom (2018), when fighting a Sinoceratops and gets taken down by the iconic "Rexy" the Tyrannosaurus rex. Later on in the movie, it escapes the "Lockwood Manor". It also appears in Michael Crichton's book "The Lost World" (1995)

 References 

Category:Abelisauridae
Category:Dinosaurs of South America
Category:Chubut Province