Phylum: Cnidaria
Class: Anthozoa
Radial or biradial symmetry
External skeleton
Septa
Tabulae
Ordovician to present
Tabulate, rugose: Ordovician to Permian (extinct at P/T extinction)
Scleractinian: Triassic to present
Colonial or solitary
Filter feeding
Reef builders
Remember, although the most well-known modern corals enjoy a symbiotic relationship with photosynthesising algae (Zooxanthellea) many modern corals do not. When thinking about Palaeozoic corals do not assume that they lived as well known corals do now.
Corals built their skeletons out of aragonite (Ordovician to Permian) or calcite (Triassic to recent). They are often preserved as moulds, casts, intact or replaced.
Phylum: Cnidaria
Class: Anthozoa
Radial or biradial symmetry
External skeleton
Septa
Tabulae
Ordovician to present
Tabulate, rugose: Ordovician to Permian (extinct at P/T extinction)
Scleractinian: Triassic to present
Colonial or solitary
Filter feeding
Reef builders
Remember, although the most well-known modern corals enjoy a symbiotic relationship with photosynthesising algae (Zooxanthellea) many modern corals do not. When thinking about Palaeozoic corals do not assume that they lived as well known corals do now.
Corals built their skeletons out of aragonite (Ordovician to Permian) or calcite (Triassic to recent). They are often preserved as moulds, casts, intact or replaced.