Fossils Found In China Reveal Answers to Centuries Old Evolution Question

An extremely rare discovery is clueing scientists in on a longtime riddle about evolution.

Around 540 million years ago, animals began appearing on Earth and have since been identified through their fossilized remains. However, many of these early animals consisted of simple tubes that the animals lived inside. Scientists struggled to know much about the animals because soft parts of the body have long decomposed.

But a 2017 discovery of the tube-like fossils, called Gangtoucunia aspera, in eastern Yunnan Province, China, equipped with the well-preserved soft parts of the animal, answers the evolutionary questions. The research team recently published its findings in a paper published by research journal Proceedings of the Royal Society B.

Luke Parry, a co-corresponding author for the study and a teaching fellow at the University of Oxford, told Newsweek in an email that before the recent discovery, some researchers believed a type of worm lived inside the tubes. Parry, an expert in annelid worms, felt the hypothesis was wrong. A discovery by doctoral student Guangxu Zhang proved his hunch.

Now, researchers know instead of a worm, the animal resembled a jellyfish.

"Guangxu's specimens are really remarkable because they preserve the soft parts, showing that Gangtoucunia had a ring of tentacles around its mouth and a gut partitioned along its length," Parry said.

"These are features that are found today only in a group called cnidarians," he continued. "This group includes jellyfish, sea anemones and corals. When I first saw the specimens I was struck that we could see these features in one of this important but puzzling early skeletal for the first time, confirming my previous suspicions that they were made by cnidarians and not annelid worms."

Zhang grew up with a passion for fossils because of his love for Jurassic Park. He believes his research is the first of its kind.

"The body of jellyfish is very soft, 95% of its composition is water, and there is no tougher tissue," Zhang told Newsweek in an email. "This makes their soft body very difficult to preserve, not to mention a 500-million-year-old, finger-long little Gangtoucunia. I'm sure I'm not the first one to dig out the soft tissue, but I think I'm the first one to realize its soft tissue preservation and study it."

The location the fossils were found in was key to the discovery. An article about the research paper by Science Daily attributed the preservation to poor oxygen conditions in the area. The conditions limited bacteria, which normally destroys the soft tissue in fossils.

The discovery reveals that the fossil was that of an early jellyfish, but the research team previously discovered similar tube fossils that were home to marine worms, worms with paired legs and annelids.

Co-corresponding author Xiaoya Ma said these discoveries could direct the team in future studies.

"During the same salvage collection at Gaoloufang site, we also discovered some other new important animal species. Therefore, my team is going to continue to work and report these new discoveries in the near future," Ma told Newsweek in an email.

Update 11/7/22, 9:57 a.m. ET: This story was updated with comment from Guangxu Zhang.