Symphysurus sp. and Xiphosuran
Early Ordovician (Arenigian)
Upper Fezouata Formation
Zagora, Draa Valley, Morocco

Spectacular 235mm slab with 100mm xiphosuran and 70mm trilobite including antennae. One of the most attractive specimens of this kind we have ever had. Very rare.

This remarkable fossil pairs a trilobite with preserved antennae alongside a xiphosuran, or horseshoe crab relative—two iconic arthropods from Earth’s ancient seas. The trilobite’s delicate antennae, rarely fossilized, offer a rare glimpse into its sensory world, revealing how it explored the seafloor. The xiphosuran, with its domed shell and spiked tail, shows the classic body plan that has changed little in over 400 million years. Together, they capture a moment in deep time—a beautifully preserved encounter between two ancient seafloor survivors.