Large Fossil African 'T-Rex' Dinosaur Tooth Cretaceous Period, 145-65 million years B.P. A Carcharodontosaurus saharicus (African T-rex) fossil dinosaur tooth, with serration and enamel clearly visible; held in a white card collector's tray. 48.5 grams, 84 mm (3 1/4 in.). Tegana Formation, Sahara Desert, Morocco, North Africa. From a Cambridgeshire, UK, collection. The Carcharodontosaurus saharicus was one of the largest predators (larger than its distant North American T-Rex cousin) of all time and is related to Allosaurus and the South American Giganotosaurus.