In the pantheon of important early animals, the Trilobite ranks high. One of the OG arthropods, Trilobites are distant relatives of modern lobsters and spiders.
They were also the first group of animals to develop complex eyes, allowing them to see objects clearly and even estimate how far away they were. The name ‘trilobite’ was given to these extinct sea creatures because their body could be split into three parts. Trilobites appeared abruptly in the early part of the Cambrian Period (around 500 million years ago.) For almost 300 million years, these arthropods thrived, but a prolonged decline set in before they finally became extinct at the end of the Permian period. That means these marine animals lived long before dinosaurs walked the earth.