Species: Elrathia kingii
Age: 498 to 513 Million years old
Trilobites are some of the most iconic and collectible fossils out there. Even though they look like pillbugs, they’re more closely related to horseshoe crabs and spiders. They first appeared during the Cambrian Explosion and stuck around until the Permian Extinction took them out, along with over 90% of marine species. But hey, over 250 million years is a pretty good run.
Of the more than 20,000 species of trilobites, Elrathia kingii are some of the best preserved ones you can find. And that’s not just luck! These guys fossilized so well because of where they lived – low-oxygen waters. Low oxygen meant there weren’t any decomposers around to break them down, letting them turn into perfect little fossils once they got buried by underwater sediment.