Ampyx (trilobite)

Ampyx is an Ordovician-Silurian genus of Asaphid trilobites of the family Raphiophoridae. Species of "Ampyx" are characterized by three extended spines on the head-shield, one spine derived from each free cheek, and one spine emanating from the glabellum. Species include "Ampyx linleyensis" (Lanvirn-Caradoc series).
Species of "Ampyx" grew to an average length of .
Collective behaviour.
Fossils of the trilobite "Ampyx priscus", dating back about 480 million years ago, have been recently described as clustered in lines along the ocean floor. The animals were all mature adults, and were all facing the same direction as though they had formed a conga line or a peloton. It has been suggested they line up in this manner to migrate, much as spiny lobsters migrate in single-file queues. Or perhaps they are getting together for mating. The findings suggest animal collective behaviour has very early evolutionary origins.
Distribution.
Fossils of "Ampyx" have been found in: