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.

“Shark-like scales from the Late Ordovician have been found, but no teeth. If these were from sharks it would suggest that the earliest forms could have been toothless. Scientists are still debating ...

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 ...