Double Xiphosurida Specimen (Pos/Neg) - Horseshoe Crab Ancestor

This is a double specimen of a Lower Ordovician arthropod which would be a member of order Xiphosurida. Xiphosurida is believed to be a very ancient ancestor or at least closely related to the modern day horseshoe crab. Both specimens are just over an inch in length and have a beautiful orange/red coloration due to the oxidation of iron pyrite. Both the positive and negative impression are included.

It comes from the Upper Fezouata Formation near Zagora, Morocco.