Carnotaurus stands out among predatory dinosaurs for its striking appearance. Its name, meaning “meat-eating bull,” references its distinctive feature: a pair of prominent, bony horns above its eyes. These horns, along with its compact body and unusually short forelimbs, contributed to its profile. Carnotaurus was a bipedal theropod that roamed South America during the Late Cretaceous period, approximately 72 to 69 million years ago. It offers a glimpse into the diversity of large predators in the Southern Hemisphere.
Primary Discovery Location
The remains of Carnotaurus were unearthed in Patagonia, specifically in the Chubut Province of Argentina. This area is renowned for its rich fossil deposits. The discovery site lies within the La Colonia Formation, a rock unit dating to the Campanian and Maastrichtian stages of the Late Cretaceous. The La Colonia Formation is characterized by sediments suggesting an environment of lagoons, tidal flats, or coastal plains, indicative of a warm climate with distinct wet and dry seasons. This geological context helps understand the ancient world Carnotaurus inhabited and how its remains were preserved.
Unearthing the Specimen
The discovery of Carnotaurus occurred in 1984 during an expedition led by Argentine paleontologist José F. Bonaparte. The expedition, supported by the National Geographic Society, focused on South American terrestrial vertebrates. The team uncovered a complete skeleton, including significant portions of the skull, spine, and limbs. Fossil preservation was notable, with extensive skin impressions found alongside the bones, particularly from the right side.
The specimen, designated as holotype MACN-CH 894, was discovered lying on its right side in a typical death pose, with the neck bent back over the torso. Recovering the fossil was a meticulous process, as the remains were embedded in hard iron-rich rock. This single, well-preserved skeleton provided significant detail about the anatomy of this unique theropod.
Significance of the Carnotaurus Find
The discovery of Carnotaurus was important for paleontology, particularly for understanding theropod evolution in the Southern Hemisphere. Before this find, well-preserved large theropods from the ancient supercontinent of Gondwana were less common. Carnotaurus became one of the best-understood members of the Abelisauridae family, a group of large predatory dinosaurs that dominated southern landmasses during the Late Cretaceous. Its anatomical features, such as the two thick, cone-shaped horns above its eyes, set it apart from other carnivorous dinosaurs.
The preserved skin impressions were significant; Carnotaurus was the first theropod found with extensive integument evidence, revealing a mosaic of small, non-overlapping scales (approximately 5 millimeters) interrupted by larger, non-bony bumps or conical studs. This provided direct evidence that Carnotaurus had scaly skin, without any indication of feathers. Its short, almost vestigial forelimbs and proportionally long, slender hind limbs suggested adaptations for speed, making it potentially one of the fastest large theropods. The forward-facing eyes also implied binocular vision, aiding depth perception for hunting. These characteristics offered insights into the predatory strategies and evolutionary paths of abelisaurids, distinguishing them from their northern counterparts like tyrannosaurids.