Carcharodontosaurus

Carcharodontosaurus (/ˌkɑːrkəroʊˌdɒntoʊˈsɔːrəs/; "sharp-toothed lizard") is a genus of large theropod dinosaur that lived in Northwest Africa from about 100 to 94 million years ago during the Cenomanian stage of the Cretaceous. The taxon was first described in 1925 by French paleontologists Charles Depéret and Justin Savornin as Megalosaurus saharicus, based on two fossil teeth discovered in Algeria, which are now lost. A partial skeleton was discovered in Egypt as early as 1914 by crews of German paleontologist Ernst Stromer, although he did not report the find until 1931. Based on this specimen, together with the teeth previously described by Depéret and Savornin, Stromer established the genus Carcharodontosaurus and its type species (species a genus in named for) C. saharicus. Although the Egyptian skeleton was destroyed during the World War II, it was subsequently redescribed as the holotype (name-bearing) specimen of a distinct carcharodontosaurid genus, Tameryraptor. In 1995, a large incomplete skull attributed to C. saharicus was discovered in the Kem Kem Beds of Morocco, which was officially proposed as the neotype (replacement holotype) in 2007. In the same year, fossils unearthed from the Echkar Formation of Niger were described and named as another species, C. iguidensis, though this taxon might belong to a different genus.

The type species reaching around 12 m (39 ft) in length and approximately 5–7 metric tons (5.5–7.7 short tons) in body mass, Carcharodontosaurus is one of the largest theropod dinosaurs known. It had a large, lightly built skull with a triangular rostrum (front of skull). Its jaws were lined with sharp, recurved, serrated teeth that bear striking resemblances to those of the great white shark (genus Carcharodon), the inspiration for the name. Though giant, its cranium was made lighter by greatly expanded fossae (depressions in bone) and fenestrae (holes in the skull), but this made the cranium more fragile than tyrannosaurids'. Studies of the bite force and tooth anatomy of Carcharodontosaurus have found it to have relatively low bite force compared to other large theropods. Despite the limited postcranial material known, is thought to have had small forelimbs, powerful hindlimbs, and a long tail that provided balance. Many gigantic theropods are known from North Africa during this period, including both species of Carcharodontosaurus as well as the spinosaurid Spinosaurus and the possible ceratosaur Deltadromeus. North Africa at the time was blanketed in mangrove forests and wetlands, creating a hotspot of fish, crocodyliforms, and pterosaur diversity.