Cambrian explosion
Trilobites

The earliest trilobite fossils are about 530 million years old, but the class was already quite diverse and cosmopolitan, suggesting they had been around for quite some time. The fossil record of trilobites began with the appearance of trilobites with mineral exoskeletons – not from the time of their origin.
change_case:english_capital, detectable_content:number_placeholders[3]