rex "Tyrant Lizard") was one of the largest and most ferocious dinosaurs to exist on Earth during the Late Cretaceous Maastrichtian period

Approximate measurements of the Polacanthus

ocupando un nicho ecológico similar al de otros grandes terópodos de su tiempo

as well as other smaller animals

This giant inhabited a predominantly terrestrial environment

Helicoprion Variant:Unprimed rex "Tyrant Lizard") was oneHelicoprion ( H. ergassaminon , 'Saw coil') is a genus of extinct cartilaginous fish that resembled sharks in appearance and behavior. This genus first emerged in the oceans of the Late Carboniferous, approximately 290 million years ago, and survived the Permian Triassic mass extinction, which occurred about 252 million years ago. However, it finally became extinct in the Late Triassic, approximately 225 million years ago. The most remarkable feature