Perspicaris

This is a rare fossil!  Perspicaris was a bivalved arthropod that was typically about one inch long, with two sides (valves) of the thorax being attached to each other by a hinged joint along the top.

This creature represents a good example of the difficulties of interpreting life styles from the fossil record. On one hand, its large eyes and flap-like appendages, plus the relative paucity of Perspicaris fossils suggest it was an active swimmer living in the water column (and hence relatively free from the hazard of being buried in a mud avalanche.) On the other hand, its lack of strong front claws suggests a relatively sparsely settled, bottom sediment feeder.