The Wikipedia article of the day for July 30, 2017 is Giganotosaurus.
Giganotosaurus ("giant southern lizard") is a genus of theropod dinosaur that lived in what is now Argentina, around 99.6 to 97 million years ago. It was one of the largest known terrestrial carnivores, but the exact size has been hard to determine from the incomplete remains found so far. The holotype specimen, discovered in Patagonia in 1993, is almost 70% complete, and indicates a length of 12 to 13 m (39 to 43 ft), a skull 1.53 to 1.80 m (5.0 to 5.9 ft) in length, and a weight of 4.2 to 13.8 t (4.6 to 15.2 short tons). A length of 13.2 m (43 ft) has been extrapolated from another individual's dentary bone. Some researchers believe the animal to be larger than Tyrannosaurus, generally considered the largest theropod. The skull was low, with a ridge-like crest in front of the eye. The teeth were serrated, and the front of the lower jaw was flattened. Giganotosaurus is thought to have had a homeothermic metabolism, between that of a mammal and a reptile, which would have enabled rapid growth but not fast movement. It was probably the apex predator of its ecosystem, feeding on juvenile sauropod dinosaurs.