English: Lythronax is the oldest known tyrannosaurid, from the Campanian era of what is now North America. It was heavily built with a robust skull, small two-fingered forelimbs, and strong hindlimbs. Lythronax had 11 tooth sockets in the maxilla bone of the upper jaw, which is fewer than most tyrannosaurids. The frontmost teeth were the largest, with the longest at around 12 cm long. Lythronax had forward-facing eyes which gave it depth perception, possibly suggesting that it was an ambush predator. Due to the incompleteness of the fossil specimen, size estimates range from 5-8 m in length.