Corals take back the reefs
With the rudist clams gone, scleractinian corals rebuild the tropical reef system they had lost.
- When
- —
- Duration
- 8 million years
- Known to
- ± 2 million years
- Era
- Paleocene, Cenozoic
Rudist bivalves had displaced corals from the best tropical carbonate platforms through most of the Cretaceous. Their extinction at the boundary leaves the niche open, and scleractinian corals — themselves badly hurt, with many genera lost — slowly reoccupy it. Reef systems remain sparse and patchy through the early Paleocene, a several-million-year gap sometimes called a reef eclipse, before recovering into the coral-dominated form that persists to the present. Every modern coral reef traces back to this reoccupation.