Synziphosurine
Early Ordovician (Arenigian)
Upper Fezouata Formation
Zagora, Draa Valley, Morocco
40mm positive on 109mm slab.

This is the first known occurrence in Africa and the earliest known occurrence of synziphosurines anywhere. They are better known from the Early Silurian to Early Carboniferous of North America and Europe.

Nice contrast between the fossil and the matrix.

A synziphosurine is a member of a suborder of arthropods, Synziphosurina, considered to be stem-group xiphosurans. In other words, based on current understanding, they may not be ancestral to xiphosurans (horseshoe crabs) but they are more closely related to their ancestors than to other groups.

Video is a 3D scan of a related Silurian specimen