A fossil of a 520-million-year-old sea creature that had 18 tentacles was recently discovered in China, and scientists believe it might be a distant relative to the comb jelly.
The fossil, which was preserved in an olive and yellow-colored mudstone and looked like a flower, was found in South China by Professor Hou Xianguang of Yunnan University, said a University of Bristol press release.
London’s Natural History Museum and scientists from the University of Bristol and Yunnan University studied the fossil and published their findings in Current Biology. According to the team, the comb jelly could be related to other seafloor-dwelling creatures, including the large fossil with polyp-like tentacles.
Dubbed “Daihua” after the Dai tribe in Yunnan, China and “Hua,” the Mandarin word for flower, the fossil is a cup-shaped organism with 18 tentacles around its mouth. There are thin, feather-like branches with rows of massive ciliary hairs preserved on its tentacles, which it most likely used to kill prey.
“When I first saw the fossil, I immediately noticed some features I had seen in comb jellies,” Dr. Jakob Vinther, a molecular palaeobiologist from the University of Bristol’s School of Earth Sciences, said in the press release. “You could see these repeated dark stains along each tentacle that resembles how comb jelly combs fossilize.”
Comb jellies today are carnivores and they swim using bands of rainbow-colored comb rows along their bodies that are composed of cilia (densely packed cellular protrusions). They’re famous for their hair-like structures, which are much larger compared to similar species.
In the study, the team explained how comb jellies evolved from animals that had an organic skeleton, which some still swam with during the Cambrian Period. The study suggests that the comb jellies’ combs evolved from tentacles found in polyp-like ancestors that moved along the seafloor. Their body transformations are also interesting: Their mouths expanded into balloon-like spheres, making their original body smaller in size so the tentacles that used to circle the mouth now emerge from the back-end of the creature.
“With such body transformations, I think we have some of the answers to understand why comb jellies are so hard to figure out,” Dr. Luke Parry, a co-author of the study, said in the press release. “It explains why they have lost so many genes and possess a morphology that we see in other animals.”