Over 100 years has passed since their discovery, yet some of the world’s most bizarre fossils have just been identified as distant relatives of humans, thanks to the work of University of Adelaide researchers.
The fossils belong to 500-million-year-old blind water creatures, known to scientists as “vetulicolians” (pronounced: ve-TOO-lee-coal-ee-ans).
These marine creatures, which have been described as alien-like in appearance, were “filter-feeder” creatures, shaped like a figure-of-8. Their odd anatomy has meant that they have not been placed correctly in the tree of life, that is, until now.
In a new paper published in BMC Evolutionary Biology, researchers at the University of Adelaide and the South Australian Museum argue for an alteration in the way that these creatures are viewed, placing them in the same group as vertebrate animals, such as humans.
“Although not directly related to humans in the evolutionary line, we can confirm that these ancient water creatures are among our distant cousins,” says the lead author of the paper, Dr. Diego Garcia-Bellido, ARC Future Fellow with the University’s Environment Institute.
“They are close relatives of vertebrates- animals with backbones, such as ourselves. Vetulicolians have a long tail supported by a stiff rod. This rod resembles a notochord, which is the precursor of the backbone and is unique to vertebrates and their relatives,” he says.
The first specimens were studied back in 1911, but it took until 1997 for the fossils to be classified as a group on their own: the vetulicolians. These fossils have now been discovered across the world including: Canada, Greenland, China and Australia.
The latest insights to vetulicolians have derived from new fossils found on Kangaroo Island off the coast of South Australia, which have been named Nesonektris (Greek for “Island Swimmer).
“Vetulicolians are further evidence that life was very rich in diversity during the Cambrian period, in some aspects more than it is today, with many extra branches on the evolutionary tree,” Dr. Diego Garcia-Bellido says. “They were simple yet successful creatures, large in number and in distribution across the globe, and one of the first representations of our cousins, which include sea squirts and salps.”
Contributing Source: University of Adelaide
Header Image Source: University of Adelaide/South Australian Museum