[caption id="attachment_82618" align="alignright" width="580"] The dorsal view of Fuxianhuia protensa is pictured in this handout image provided by Xiaoya Ma.
CREDIT: REUTERS/XIAOYA MA/HANDOUT[/caption]

Scientists revealed Monday that an extraordinary fossil found in southwest China may point to the first fully developed circulatory system. Called Fuxianhuia protensa, the crustacean-like creature lived approximately 520 million years ago, during the Cambrian period.

A paleontologist with London's Natural History Museum, Xiaoya Ma, said that it is "extremely rare and unusual" to see such a high level of preservation of soft tissues after death. These tissues tend to decay quickly, leaving only shells, teeth and bones that are typically found in fossils. Ma further stated that "exceptional circumstances" can cause organs and tissue to remain intact.

The Fuxianhuia protensa fossil contains a heart in the center of the body, with a complex network of blood vessels going to the brain, eyes, legs and antennae. A cardiovascular system delivers nutrients and oxygen and is present in most animals, with the exception of flatworms and jellyfish, which do not have a body cavity.

The discovery offers more information on the evolution process and reveals a number of creatures living today have a strong resemblance to those alive many millions of years ago.

The Fuxianhuia protensa was around five inches long and had numerous legs, with an exterior exoskeleton. Along with the antennae, it possessed rotating stalked eyes that gave it a wide field of vision to aid in navigation. It lived in shallow water and walked on the seabed, although whether it was a scavenger or predator is unclear.

The level of preservation suggests the creature was entombed during a cataclysmic event similar to Pompeii, possibly a mudslide under the water. Other Fuxianhuia protensa fossils have been found in the area, with one having the oldest known brain. While it is thought that other creatures with a cardiovascular system existed earlier on, there is no evidence of it in fossils.

Online:
http://www.reuters.com/article/2014/04/07/us-science-heart-fossil-idUSBREA3619E20140407