Aegirocassis benmoulai Van Roy 2015

Ordovician

Lower Fezouata Formation

Eastern flank of Jbel Tigzigzaouine, facing Oued Ezegzaou, Morocco.

105mm dorsal flap on 175mm slab. These structures were originally mistakenly thought to be the carapaces of phyllocarid arthropods, much like the original Anomalocaris from the Burgess Shale was describd as a shrimp. Extremely rare example of one of the largest arthropods of all time.

Soft-bodied.  Arthropod.

Aegirocassis is a genus of anomalocaridid arthropod that was one of the largest arthropods that have 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.

Aegirocassis is known only from the Early Ordovician of Morocco.

Have a look at this amazing 3D model of Aegirocassis courtesy of Google and darwinmuseum.ru. Click on the arrows at the bottom right corner to see it full screen!