A Bull-Horned Carnivore's Hide
In 1984, paleontologist José Bonaparte led an expedition into Argentina's Chubut Province that uncovered a singular fossil. On a farm named "Pocho Sastre," the team found a nearly complete and articulated skeleton of a large predatory dinosaur. The fossil was so remarkable that it became the only known specimen of its kind: Carnotaurus sastrei, a name that means "Sastre's meat-eating bull." The name references both the ranch owner, Angel Sastre, and the dinosaur's most prominent feature: two thick, 15 cm (5.9 in) horns protruding from above its eyes.
What made this discovery exceptional were the extensive skin impressions found preserved along the skeleton's right side. While skin from the skull was accidentally destroyed during preparation, patches from the jaw, neck, shoulder, and tail remained. This fossil provides the most complete look at the skin of any large theropod. The skin was a mosaic of small, non-overlapping polygonal scales, each about 5 millimeters in diameter. Studding this scaly hide were larger, conical bumps, or "feature scales," measuring 4 to 5 cm in diameter. These were distributed randomly across the animal's body and lacked any bony core. The discovery confirmed that at least one lineage of large theropods was completely scaly, showing no evidence of feathers.