Description

Aegirocassis benmoulai

Ordovician

Fezouata Formation

Mecissi-Zagora Region, Draa Valley, Morocco.

28mm anomalocaridid appendage on 59mm slab.

Soft-bodied. Arthropod.

Aegirocassis is a genus of anomalocaridid known only from the Early Ordovician of Morocco.  It was one of the largest of all arthropods that ever lived, reaching about 6 1/2 feet long and was almost certainly the largest animal of its time.  Like the largest animal of our time, the blue whale, it has been determined to have been a filter-feeder that descended from predatory ancestors.