Carnotaurus

Dinosaurs > Carnotaurus

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. Derived from the Latin carno [carnis] (“flesh”) and taurus (“bull”), the name Carnotaurus means “meat-eating bull”, alluding to its bull-like horns. 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 may have been closer to either Majungasaurus or Aucasaurus.

Carnotaurus was a lightly built, bipedal predator, measuring 8 to 9 m (26 to 30 ft) in length and weighing at least 1.35 metric tons (1.33 long tons; 1.49 short 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 and slender hindlimbs. The skeleton is preserved with extensive skin impressions, showing a mosaic of small, non-overlapping scales measuring approximately 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.

The distinctive horns and the muscular neck may have been used in fighting conspecifics. According to separate studies, rivaling individuals may have combated each other 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.

Carnotaurus

Clade: Dinosauria
Suborder: Theropoda
Family: Abelisauridae
Clade: Brachyrostra

Size: 9 m (30 ft) long

Weight: 1.35 metric tons

When: Cretaceous Period
72to 69 million years ago

Where: Argentina

Diet: Carnivore

Carnotaurus is the only known carnivorous bipedal animal with a pair of horns on the frontal bone. The use of these horns is not entirely clear; several interpretations have revolved around use in fighting conspecifics, in display, or in killing prey.

Greg Paul (1988) proposed that the horns were butting weapons and that the small orbita would have minimized the possibility of hurting the eyes while fighting. Gerardo Mazzetta and colleagues (1998) suggested that Carnotaurus used its horns in a way similar to rams. They calculated that the neck musculature was strong enough to absorb the force of two individuals colliding with their heads frontally at a speed of 5.7 m/s each. Fernando Novas (2009) interpreted several skeletal features as adaptations for delivering blows with the head. He suggested that the shortness of the skull might have made head movements quicker by reducing the moment of inertia, while the muscular neck would have allowed strong head blows. He also noted an enhanced rigidity and strength of the spinal column that may have evolved to withstand shocks conducted by the head and neck.


Source: Wikipedia