Trilobite
Featured in this listing is an Elrathia Kingii trilobite of the mid-Cambrian, 513-498 Million Years ago.
Elarathia Kingii, alongside other complex animals, emerged during this period which was known as the 'Cambrian Explosion' when live evolved beyond mostly single-celled organisms living in colonies, to complex multicellular creatures like this trilobite.
These trilobites are therefore some of the earliest known animals in the fossil record. They are typically found in the Wheeler Formation in Utah, USA. The photo shows a typical specimen, not necessarily the one in the photograph.