← Rex's Notes
Spinosaurus
Sail on its back, paddle for a tail.
Said: SPINE-uh-SOR-us
Era: Cretaceous · 99 to 93 million years ago
Diet: Carnivore
Habitat: River systems of North Africa
Size: longer than a city bus, with a sail taller than an adult.
What it was like
Spinosaurus spent more time in water than any other dinosaur we know of. It had a long crocodile-shaped snout for catching fish and a flat tail like a paddle.
What we know now
A 2020 paper on a Moroccan tail described an eel-like, flexible morphology and proposed Spinosaurus as a pursuit-swimmer; subsequent work (notably Sereno and Myhrvold, 2022) has pushed back, favoring a heron-like wader interpretation. Bone density is unusually high, consistent with at least frequent submersion. The original Egyptian holotype was destroyed in a WWII Allied bombing raid in 1944.
Notes
- Larger than T. rex by length, though probably lighter.
- Conical teeth designed to grip slippery prey, not slice.
- The sail may have been a display structure or a thermoregulator.