Oldest Animal Species on Earth

 

Jellyfish

These gelatinous creatures without a brain, bones, or heart have been on Earth for about 500 million years. Jellyfish are the oldest multi-organ animal in the world and have existed in some form for at least 500 million years. The oldest known definitive jellyfish fossil dates back to 500 million years. Research on the fossil was released in 2007 and states that it is over 200 million years older than the previously oldest jellyfish fossils. New studies from around 2011, have revealed that jellyfish are more complex than previously thought. One marine biologist disputed the conventional wisdom that jellyfish lack a central nervous system. He said that the nervous system of jellyfish might not be as obvious as it is in animals with a brain connected to a spinal cord, but it is distinct in its own way.