Ordovician reefs were also home to large sea lilies, relatives of sea stars. Anchored to the bottom inside calcareous tubes, they collected food particles with feathery arms that waved in the ...

The Ordovician world was a watery one in which vast oceans covered almost the entire northern hemisphere. In the south, the mega-continent of Gondwana drifted. According to the University of ...

But first there was a period of biological regrouping following the disastrous climax to the Ordovician. The recovery soon got under way in the oceans as climbing temperatures and rising sea ...