Quick answer: a Spinosaurus tooth is conical, nearly round in cross-section, with long ridges running down the enamel and no obvious serrations. A Carcharodontosaurus tooth is flat and blade-like, curved backwards, with fine serrations along both edges.
Two giant predators from the same river system
Both dinosaurs lived in the Cretaceous river and delta environments of what is now eastern Morocco, preserved in the Kem Kem beds. Their teeth are among the most popular dinosaur fossils for collectors. Because they come from the same deposits, it helps to know the differences.
Side-by-side comparison
| Feature | Spinosaurus | Carcharodontosaurus |
|---|---|---|
| Overall shape | Conical, fairly straight | Flattened blade, curved backwards |
| Cross-section | Round to oval | Narrow oval, laterally compressed |
| Edges (carinae) | Smooth, without clear serrations | Serrated front and back edges |
| Enamel surface | Long vertical ridges (fluting), often glossy | Smoother, often with wavy wrinkles near the edges |
| Likely diet | Adapted for gripping slippery prey such as fish | Adapted for slicing flesh of large animals |
How to identify a Spinosaurus tooth
- Look at the shape. It resembles a large cone or a crocodile tooth more than a knife.
- Check the cross-section. Viewed from the tip, it is close to round.
- Look for fluting. Fine vertical ridges usually run along the enamel.
- Feel the edges. They are smooth, without the saw-like serrations of other large theropods.
How to identify a Carcharodontosaurus tooth
- Look at the profile. It is flat, wide and curved, like a blade.
- Check both edges. Use a magnifying glass: you should see fine serrations along the front and back.
- Look for enamel wrinkles. Many teeth show curved wrinkles in the enamel near the serrated edges.
Teeth that are easily confused
Some Kem Kem teeth from large crocodile-like reptiles are also conical and can be mistaken for Spinosaurus. Smaller blade-like theropod teeth from other species can be mistaken for juvenile Carcharodontosaurus. If a tooth does not fit the descriptions above clearly, the safest label is a broader one, such as “theropod tooth.”
Tips before buying
- Ask for clear photos of both sides, the edges and the base.
- Ask whether the tooth has been repaired or restored, and where.
- Check that the listed size matches the photos with a scale.
Frequently asked questions
Which is rarer?
Both are common in the Kem Kem beds compared with dinosaur fossils from many other regions. Large, complete teeth with intact tips and serrations are scarcer and more valuable.
How old are these teeth?
They come from the mid-Cretaceous Kem Kem beds, roughly 100 million years old.