Rugose and tabulate corals are first recognised in the Ordovician, going extinct at the Permo-Triassic extinction. Scleractinian corals are first recognsied in the Triassic, and continue to the present day. Some (but not all!) species of corals have been important reef builders, in the present day and the geological past... Read more
- Phylum: Cnidaria
- Class: Anthozoa
These are the features that will help you to identify fossils as corals.
- Radial or biradial symmetry
- External skeleton
- Tabulae (not for Rugose corals!)
Ordovician to present