What kind of fossil is this?

How long ago do you think it was alive?

Where do you think it lived?

This is a fossilized trilobite! Trilobites were related to (and sometimes ancestors to) modern arthropods, invertebrates with exoskeletons, which includes insects and spiders, among others.

Trilobites are now extinct, but they lived between 500 million and 250 million years ago. They lived mostly in the ocean seabed, but some also crawled around on land. Interestingly, some trilobites were able to roll into a ball in order to protect themselves! (Did you notice that we have done this artifact before? That wasn't a mistake -- like good scientists, we like to revisit all the artifacts now and again so that we can update how we understand them, because there are always new questions!)

For more information, visit:

• This artifact in the Karshner Digital Collections
• Artifact Worksheets you can use in your classroom or for homeschool
• Trilobite Website [AMNH]
• Trilobites [BGS]
• When Trilobites Ruled the Earth [NY Times]