TF1103 Rugose coral

Ordovician to Permian

Phylum: Cnidaria
Class: Anthozoa
Order: Tabulata

Septa
Colonial
Columella
Polyps

Mineral replacement of skeleton
Precipitation of minerals in spaces

The presence of columella (central support structures) and septa allow identification of this fossil as a colonial rugose specimen. Columella are not present in tabulate corals as these are always colonial, and do not need the extra support.
Solitary rugose corals developed columella as an internal support structure, and it was retained for some colonial forms, such as this one.