?Middle Ordovician, Late Ordovician – Early Silurian
Billingsariidae is an extinct family of stationary epifaunal suspension feeders which have been interpreted to have hosted symbiotic algae in their tissues
Description of the Family
- Corallum cerioid
- Corallites slender
- Septa short, stout, alternating in size
- Tabulae horizontal
- Corallum cerioid partly asteroid; corallites slender; septa short, stout, in some alternating in size, each a series of near vertical large monacanths; communication between neighboring tabularia rare to absent; tabulae horizontal; axial trabeculae may occur, forming discontinuous axial structure.