ANOMALOCARIS. PRECAMBRIAN/3

"The shark of the Cambrian,"Anomalocaris was the largest animal in the Cambrian seas and probably the most effective predator of its day. This carnivore swam in the open sea, probably undulating through the water like a manta ray. It used its claw-like feeding appendages to seize prey and carry it to a round mouth lined with teeth.

http://www.youtube.com/watch?v=iEh6ufop6tE

Anomalocaris are some of the most widely distributed of the Burgess Shale animals.  It is the largest known Burgess Shale animal. Some related specimens found in China reach a length of six feet! The giant limbs in front, which resemble shrimp tails, were used to capture and hold its prey. A formidable mouth on the undersurface of the head had a squared ring of sharp teeth that could close in like nippers to crack the exoskeleton of arthropods or other prey. With those large eyes and a body half flanked with a series of swimming lobes, this must have been an active, formidable predator.