The Paleozoic era's Silurian period saw animals and plants finally emerge on land. But first there was a period of biological regrouping following the disastrous climax to the Ordovician.

Researchers reveal Prototaxites, a giant Devonian fossil, was not a fungus or plant but a unique extinct lineage.

The most formidable of them were the armored placoderms, a group that first appeared during the Silurian ... these marine animals survived until the end of the Cretaceous period, 65 million ...