The article discusses the discovery of Spinosaurus aegyptiacus, a dinosaur that lived and thrived in water. At over 50 feet long, it was larger than T. rex and had adaptations for an aquatic lifestyle like paddle-like limbs and a elongated tail. While bones of Spinosaurus were first found 100 years ago, the full implications of it being a swimming dinosaur were only determined recently by analyzing a new fossil discovery. This changes understanding of dinosaurs, showing they were not exclusively land-dwellers and one species evolved to be fully aquatic.