Carcharodontosaurus

Carcharodontosaurus, (genus Carcharodontosaurus), genus of massive predatory dinosaurs that inhabited North Africa approximately 99–94 million years ago during the Cenomanian Age (100.5 to 93.9 million years ago) of the late Cretaceous Period (145 to 66 million years ago). Carcharodontosaurus belongs to the order Saurischia—the lizard-hipped dinosaurs—and the suborder Theropoda. It is among the largest land-dwelling carnivores in Earth’s history, with the dinosaur’s length estimated to be as much as 13.7 meters (45 feet). The genus, which is classified in the family Carcharodontosauridae, is made up of two species: Carcharodontosaurus saharicus, whose fossils were found in present-day Morocco, Algeria, and Tunisia, and C. iguidensis, whose fossils were unearthed in present-day Niger. The name Carcharodontosaurus, deriving from Greek roots, means “sharp-toothed, or shark-toothed, lizard.”

Form and function

Estimates of the body dimensions of C. saharicus and C. iguidensis have been made from fossil teeth, incomplete skulls, and other bone fragments. Based on calculations stemming from the size of the massive skull of C. saharicus, which measured approximately 1.6 meters (5.2 feet) long, paleontologists estimate that the species probably grew to a length of 13.7 meters (45 feet) or more. Model estimates of body mass, which were based on the dimensions of other similarly sized theropods, suggest that C. saharicus weighed roughly 6 metric tons (6.6 short tons). Similarly, the fossil skull of C. iguidensis measured 1.75 meters (5.7 feet) long, which allowed the dinosaur’s total length to be estimated at 13–14 meters (42–46 feet). Like those of other theropods of comparable size, such as Tyrannosaurus rex and Giganotosaurus, the jaws of Carcharodontosaurus contained several large teeth. Estimates suggest that Carcharodontosaurus had approximately 60 teeth, many of which were as long as 15 cm (6 inches) and serrated.

Carcharodontosaurus was most likely a bipedal dinosaur, meaning that it stood upright and walked or ran on its two hind limbs. The morphology of the dinosaur’s skull and dentition suggest that it was a predator, and paleontologists hypothesize that it fed on large herbivorous sauropod dinosaurs. The characteristics of the rest of the dinosaur’s form remain speculative. Some studies, however, contend that the dinosaur’s forelimbs may have been small compared with its hind legs, like those of Tyrannosaurus rex; a 2022 study describing Meraxes gigas, a closely related carcharodontosaurid, noted its reduced forelimbs and suggested that the forelimbs of Carcharodontosaurus could have followed a similar evolutionary path.

Discoveries

The first fossil evidence of Carcharodontosaurus consisted of only several teeth and fragments of bone collected in Egypt by German paleontologist Ernst Stromer von Reichenbach in the early 20th century. The fossils were described in the scientific literature at that time and then stored at the Bavarian State Collections of Paleontology and Historical Geology in Munich. During World War II the specimens were destroyed during a bombing run conducted by the Royal Air Force in 1944. The event created a long-standing mystery for modern paleontologists: left with only a description of the fossils in outdated scientific literature, scientists had no clue as to which dinosaur species they belonged to. The mystery was not solved until 1995, when American paleontologist Paul Sereno and his team uncovered a skull of Carcharodontosaurus from the Kem Kem region of the Sahara in Morocco, which they subsequently matched to the descriptions given by Reichenbach in the scientific literature. This specimen and others excavated from Algeria and Tunisia were assigned to the species C. saharicus. Later, Carcharodontosaurus fossils unearthed in Niger and first described in 2009 by American paleontologist Stephen Brusatte were assigned to C. iguidensis on the basis of differences in skull structure between the specimen and C. saharicus.