Eon: Phanerozoic
 Era: Paleozoic
  Period: Cambrian
   Epoch: Furongian
    Age: Paibian*

A smack of jellyfish

A smack, or swarm, of jellyfish swim the Panthalassic Ocean 500 million years ago during the Cambrian Period. The seabed is populated with variations of the extinct genus Vauxia, an early branching sponge.

Jellyfish, AKA sea jellies, are free-swimming organisms from the phylum Cnidaria and may have been among the first mobile macro life forms to evolve on Earth. Their distinguishing feature is specialized cells that they use mainly for capturing prey. Their bodies consist of a non-living jelly-like substance, sandwiched between two layers of tissue that are mostly one cell thick. There are approximately 9,000 species of Cnidaria today. As the fossil record of jellyfish is sparse, those illustrated here are representative of the phylum Cnidaria and are not intended to represent any specific class or order of jellyfish.