Radiocyatha

Radiocyatha is an extinct group of sponge-like animals which lived in the early to mid-Cambrian Period (Tommotian to Toyonian).

One major difference is that the radiocyath skeleton is not composed of tiny calcite grains, but rather large aragonite plates, known as nesasters.

Uranosphaera is a simple single-walled radiocyath, while the hetairacyathids bear an additional nested wall layer, akin to archaeocyaths.

[1] Radiocyaths reached their maximum abundance in the Atdabanian and Botomian, contributing towards the biomass of archaeocyath sponge reefs in regions such as Mongolia and Australia.

[2] Radiocyaths have been compared to the enigmatic receptaculitids, which also have calcareous plates and radiating rod-like structures.