Unusual Symphysops Cyclopygid Trilobite with Large Eyes

Description: This is a fine example of an Ordovician Moroccan trilobite known as Symphysops. Notice the placement of the enormous eyes at the side of the cephalon. The trilobite is thought to have been mesopelagic, meaning that it lived in the depths of some 200 meters. They slowly moved along filtering plankton. They lived in the dim twilight zone, and so needed large eyes to gather in light. Studies have shown their eyes to be similar to those of modern insects and crustaceans that live in dim light. Notice the exceptionally well-preserved eye facets in the left eye. The right side, if present, is still in the matrix.. Interestingly, some of these deep-water pelagic tributes possessed square rather than hexagonal lenses for reasons as yet unknown. This one is the first I have had on offer preserved in both 3-D and with fine facets present. Most examples are seen quite flattened in dorsal aspect with no facets visible.