Fossil: Metacanthina
Trilobites dominated the waters around the world for millions of years. They were the first free-swimming creatures of any size. The first to have an external skeleton for armor, and the first to have jointed legs. The petrified bodies and casts, or imprints, of Trilobite remains tell us of the creature’s existence. Their three lobes earned them the name Trilobites. Trilobites appeared in the seas about 700 million years ago and were prolific by the time they vanished 350 million’s years later.
