The Paleozoic era, particularly the Silurian and ... that these organisms often hosted various symbionts, including corals and shelly tubes. The findings indicated that while some symbionts ...

The Paleozoic era's Silurian period saw animals ... Previous reef-builders such as bryozoans were joined by corals and prehistoric sponges known as stromatoporoids, which formed a hard outer ...

Corals are the most well-known reef-builders ... sponge-like organisms that played a major role in reef-building during the ...