Aglaspis sp.
Late Cambrian
Weeks Shale Formation
House Range, UT, USA

Rare 0.5 inch soft-bodied aglaspidid arthropod. Highly unusual.

This is one of those bizarre arthropods that looks like a trilobite, and may be related to them, but belongs to to the Class Artiopoda.

Aglaspids survived into the Early Ordovician but died out by the end of the period.  It has been proposed that they are related to the ancestors of horseshoe crabs and arachnids.