Spinosaurus was essentially an enlarged version of Tyrannosaurus rex with a larger sail on its back.
Spinosaurus (Spinosaurus aegyptiacus) was a distinct theropod with a fundamentally different anatomy and lifestyle from T. rex. Recent discoveries in North Africa reveal Spinosaurus was semi-aquatic with paddle-like tail flukes, dense bone for diving, and specialised adaptations for piscivory (fish-eating). It reached perhaps 15 metres in length but had a different body plan including longer forelimbs, different skull proportions for fish-catching, and upright sail spines on its back formed from neural processes. It was not a larger version of T. rex but rather a specialised semi-aquatic predator occupying a different ecological niche.