Researchers have found the earliest-known heart and blood vessels in the fossil of an ancient arthropod.
The research team found the cardiovascular system in an extremely well-preserved fossil of an arthropod that lived 520 million years ago, a London Museum of Natural History news release reported.
The species, dubbed Fuxianhuia protensa, is one of the most well-known fossils anatomically; in the past researchers were able to examine the ancient creature's complex nervous system.
"This is a significant discovery," museum palaeontologists Dr Xiaoya Ma, said in the news release. "Traditionally, there was a wide assumption that such delicate internal organ structures could not survive fossilisation, a theory now challenged by the recent discoveries of nervous and cardiovascular systems. These were not only preserved, they were preserved in exquisite detail."
The specimen was discovered at the Chengjiang fossil site in southwest China, which holds some of the oldest-known Cambrian fossils. The site holds the ancestors of many modern species; since f. protensa is an arthropod it is part of the group that encompasses "insects, spiders, lobsters and millipedes," the news release reported.
The researchers used X-ray technology to look at f. protensa's complex system of blood vessels. The fossil's nervous system showed a connection between the brain and blood vessels.
The team observed a "tubular heart" near the animal's back, as opposed to in the chest cavity. Paired blood vessels extended throughout the body's segments; there were also blood vessels concentrated around the brain.
"The body plan of F. protensa acquired at the time was obviously successful enough to still be used in today's arthropods," Dr. Ma said. "These key evolutionary innovations might also have contributed to the success of arthropods as a whole. They have the longest fossil record of any animal and are the largest phylum today."
Researchers hope the imaging techniques that allowed them to examine F. protensa's anatomy will help them make more discoveries about the development of ancient creatures.
"The preservation here has opened our minds to the possibilities," Ma said. "This kind of information can answer lots of vital questions about the origin and early evolution of many animal groups."
The researcher could also help researchers gain insight into the animal's behavior, a University of Arizona news release reported.
"With that, we can now start speculating about behavior," Nicholas Strausfeld, a Regents' Professor of Neuroscience at the University of Arizona's Department of Neuroscience, said in the news release. "Because of well-supplied blood vessels to its brain, we can assume this was a very active animal capable of making many different behavioral choices."
