Trilobite

Class of extinct, Paleozoic arthropods

Trilobites (meaning "three-lobed entities") are extinct marine arthropods that form the class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described. Because trilobites had wide diversity and an easily fossilized mineralised exoskeleton made of calcite, they left an extensive fossil record.

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