Xiphosurine
Ordovician
Upper Fezouata Formation
Zagora, Morocco.

42mm on 135mm slab. Extremely high quality prep. Even the legs are preserved. Probably the best we have ever had.

Xiphosurine is a term referring to a member of the arthropod Order Xiphosura, the group that includes all horseshoe crabs and their close relatives, extinct and extant.  This group is more closely related to arachnids than crustaceans.

This specimen may represent the earliest-known form belonging to the Xiphosura – perhaps too primitive to call it a horseshoe crab. Preparation was done unusually well. It has been 3-dimensionally prepped out on all sides to stand slightly above the matrix. Very high quality and displayable.