Early Ordovician (Arenigian)

Upper Fezouata Formation

Zagora, Draa Valley, Morocco

51mm aglaspidid on 119mm x 114mm slab.

Arthropod, Aglaspid. Aglaspidid. Lagerstatten. Fezouata.

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