Image: Rudist bivalve, Sphaerulites sp.
Rudist bivalve (mollusc). France, Late Jurassic, 150 million years ago.
- Anne Musser
- © Australian Museum
Rudist bivalves were the main reef-builders in the Jurassic and Cretaceous. Modern bivalves, like oysters and clams, are still common in shallow marine areas today.