It looked like something that might have been seen by Ringo as he peered out the window of the Yellow Submarine while
tripping searching for an octopus’s garden but the Hallucigenia sparsa is no hallucination. New research has confirmed that it’s the ancestor of today’s velvet worms and that the scientists who first discovered may have actually been hallucinating because they pictured it upside down and backwards.
As reported in the journal Nature, researchers at Cambridge University studied Hallucigenia fossils found in the Burgess Shale in Canada's Rocky Mountains dating back 505 million years to the Cambrian Explosion, a period when most modern animal groups first appeared. When Hallucigenia fossils were first discovered and identified in the 1970s, the spines on its back were thought to be its legs, the legs to be back tentacles and the head and tail were reversed. Well, it WAS the 70’s.
The Cambridge group studied the Hallucigenia fossils again and turned everything around. They also studied the claws at the end of the legs and saw that they were layered cuticles stacked one inside of each other in a manner similar to Russian nesting dolls and , more importantly, to the jaws of modern velvet worms, which are actually legs that have evolved for chewing. This is the first solid evidence of a link between the velvet worm and the Hallucigenia, proving it wasn’t a one-hit Cambrian wonder with no descendents.
In the process of turning the Hallucigenia upside down and discovering its claws, the researchers did the same for some evolutionary theories about arthropods, says study co-author Dr. Javier Ortega-Hernandez.
An exciting outcome of this study is that it turns our current understanding of the evolutionary tree of arthropods -- the group including spiders, insects and crustaceans -- upside down. Most gene-based studies suggest that arthropods and velvet worms are closely related to each other; however, our results indicate that arthropods are actually closer to water bears, or tardigrades, a group of hardy microscopic animals best known for being able to survive the vacuum of space and sub-zero temperatures -- leaving velvet worms as distant cousins.
And you thought spiked worms were only found in mescal.