Washington: Researchers have found a fossil of 520-million-year-old shrimp-like creatures, which had "modern" hearts and blood vessels.
The findings of the international team of researchers from the University of Arizona, China and the United Kingdom sheds new light on the evolution of body organization in the animal kingdom and shows that even the earliest creatures had internal organizational systems that strongly resemble those found in their modern descendants.
The 3-inch-long fossil was entombed in fine dustlike particles - now preserved as fine-grain mudstone - during the Cambrian Period 520 million years ago in what today is the Yunnan province in China.
Found by co-author Peiyun Cong near Kunming, it belongs to the species Fuxianhuia protensa, an extinct lineage of arthropods combining advanced internal anatomy with a primitive body plan.
Nicholas Strausfeld , who directs the UA Center for Insect Science, said that the animal looks simple, but its internal organization is quite elaborate. For example, the brain received many arteries, a pattern that appears very much like a modern crustacean.
In fact, Strausfeld pointed out, Fuxianhuia`s vascular system is more complex than what is found in many modern crustaceans.
He said that it appears to be the ground pattern from which others have evolved, asserting that different groups of crustaceans have vascular systems that have evolved into a variety of arrangements but they all refer back to what they see in Fuxianhuia.
Strausfeld said that over the course of evolution, certain segments of the animals` body became specialized for certain things, while others became less important and, correspondingly, certain parts of the vascular system became less elaborate.