A group of international scientists have discovered the earliest example of an advanced cardiovascular system. The well-formed heart and blood vessels were found inside the body of a 520-million-year-old shrimp-like species.

"This is the first preserved vascular system that we know of," said Nicholas Strausfeld, a neuroscience professor at the University of Arizona's Department of Neuroscience, who aided in analyzing the fossil.

The ancient shrimp -- a specimen of the now-extinct arthropod species known as Fuxianhuia protensa -- was discovered amidst rich fossil deposits in the Yunnan province of China. The delicate organs were preserved thanks to the unique geological properties of what scientists consider the Pompeii of the invertebrate world.

In the unique Chinese fossil deposits, thousands of ancient creatures from the Cambrian Period, roughly 520 million years ago, were quickly entombed by fine dust particles -- the result of some catastrophic event. The entombed animals were then pristinely preserved in fine-grain mudstone.

Strausfeld says the vascular system found in the ancient shrimp is more advanced than the circulatory organs of many modern crustaceans.

"It appears to be the ground pattern from which others have evolved," he said. "Different groups of crustaceans have vascular systems that have evolved into a variety of arrangements but they all refer back to what we see in Fuxianhuia."

Scientists from the University of Arizona, China and the United Kingdom collaborated on the remarkable discovery, the details of which are laid out in the latest edition of the journal Nature Communications.

[Nature Communications]