The skull of the Yi qui was small and elongated

sensing the imminent danger

In addition to these unique features

approximately 73 to 65 million years ago

Acrocanthosaurus atokensis Scale:1:60 The skull of the YiAcrocanthosaurus atokensis is the only known species of the extinct genus Acrocanthosaurus, a carcharodontosaurid theropod dinosaur that inhabited North America during the Cretaceous period, approximately 125 to 99. 6 million years ago. It stands out for the tall neural spines on many of its vertebrae, which suggest the presence of a kind of "hump" on its neck, back and hips. It was one of the largest theropods, with a length of up to 11. 5 meters and