Diminutive Ordovician Aglaspid Fossil

This arthropod is a member of the Aglaspida. The Aglaspids resemble the modern-day horseshoe crabs, and contain as the most famous member Beckwithia typa, a monster at over 200 mm in overall length which is thought to have been a predator of trilobites. Aglaspids are thought by some to have made the trackways termed Protichnites. This taxon represents one of the youngest members of the clade. While most are known from substantially larger specimens, this is the smallest I have ever come across made all the more desirable by the fact that both the part and counterpart are here available. The positive is contained on the larger matrix half. Notice the segmentation, visible even on such a small example.