Early Ordovician (Arenigian)

Upper Fezouata Formation

Zagora, Draa Valley, Morocco

Huge 130mm on 176mm slab.

Arthropod.  Aglaspid. Aglaspidid. Lagerstatten.

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 aglaspids are related to the ancestors of horseshoe crabs and arachnids.