Early Ordovician (Arenigian)
Upper Fezouata Formation
Zagora, Draa Valley, Morocco

114mm slab with 3 aglaspids, each about 7mm.

Arthropod. Multiple. Lagerstatten. Soft-bodied. Agalaspidid.

Aglaspids are best-known from the Late Cambrian but they survived into the Early Ordovician, dying out by the end of the period.  It has been proposed that they are related to the ancestors of horseshoe crabs and arachnids.