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Tabulate Corals

Mound Shaped

Tabulate corals are colonial corals. The entire tabular coral is called the corallum, while the individual tubular chambers within the corallum are called corallites. While solitary forms of rugose corals were made up of a single corallum with large, cup-shaped calices (cups), most tabulate corals had a large corallum comprised of a colony of corallites (sometimes thousands) with very small calices in which the actual coral animals (polyps) lived. Although the individual coral polyps were generally smaller than their rugose cousins, their colonies often grew to much larger sizes. These types of coral mounds were the reef formers of the Silurian and Devonian seas.

The individual corallite chambers contain thin plates called tabulae (TAB-yu-lee in English, or tah-BOO-lye in classic Latin), which extend across the chambers. The tabulae are what this order of corals are named for. All tabulate corals have tabulae, but they are only obvious in fossils, when the sides or insides of the fossils are exposed. The tabulae are stacked within each corallite, and define successive living chambers of the coral polyp, as it grew. As each coral polyp grew it abandoned its old living compartment and secreted a new skeletal tabula above the old one resulting in the stacked living chambers seen in fossils.