Fish started becoming more widespread in the ... group-living animals that built coral-like structures. Ordovician reefs were also home to large sea lilies, relatives of sea stars.

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 ...

The earliest fossil evidence for sharks or their ancestors are a few scales dating to 450 million years ago, during the Late Ordovician Period. Emma Bernard, a curator of fossil fish at the Museum, ...

Fish were now diversifying and extending their ... still positioned over the South Pole but the vast icecaps of the late Ordovician period melted almost to nothing. Sediments formed from massive ...