First discovered in 1977, the fossilized remains of a creepy creature with bizarre body parts and appearance was named "hallucigenia" by Simon Conway-Morris, the British paleontologist that discovered it. He wrote that it had a "dream-like quality" and ever since then scientists have been trying to figure out more about it.
Researchers surmised that hallucigenia lived around 508 million years ago. It was discovered in the Burgess Shale in Canada and was like nothing Conway-Morris had seen before. It's long body was tube shaped and contained 7 pairs of spiny appendages that stuck out of one side and seven pairs of tentacles on the other side that appeared to have mouth parts on the ends. There was no way to tell which end was the head and which was the back, because other than a blob like tip on one end, it was pretty non-descript.
At the time, it was believed that the spines were used as legs, as the creature crawled along the bottom of the sea floor and the tentacles were used to catch food from the water above. That theory was debunked in 1991 when a set of similar fossils was found in China. Research on those creatures revealed that the tentacles were actually legs, the lips on them were really claws and the spines stuck out of the back for defense. Basically, earlier conclusions about hallucigenia had been upside down.
While the Chinese fossil may have shed light on how hallucigenia moved, there was still no clear agreement about where the head was. The end that had the blob on it was debated by scientists, with some thinking it was a head and others theorizing that the blob was created when bodily fluids leaked out of the animal when it died.
However, two researchers, using modern microscopy analysis seem to have figured out what no else has. Martin Smith, a research fellow in the Department of Earth Sciences at the University of Cambridge and Jean-Bernard Caron of the Royal Ontario Museum say that their analysis shows that the blobby end of hallucigenia is not the head. The other end is, since their examination with an electron microscope shows two distinct dots, which appear to be eyes. There is also a mouth at this end of the creature, which appears as a small hole with a ring of spines, leading to a throat full of sharp teeth. Smith and Caron also learned much about the how the spines and legs of hallucigenia worked. There were ten pairs of limbs in all; the first three nearest the head were likely used as antennae. The remaining seven had no joints, but the team theorizes that the seven pairs of spines might have been where large muscle groups that powered the legs were anchored.
It is believed that hallucigenia is part of the ecdysozoan group, which includes spiders, insects and other crustaceans. In an interview with National Geographic magazine, Smith talked about the most important part of the research, finally figuring out which end was up, "I think it's pretty unambiguous what we're looking at. I don't think we're going to turn it over again back to front."
Check out the video below for more information on this weird worm.
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