505 Million Year Old “Weird” Worm Becomes An Ancestor

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Canada’s Burgess shale located in the Canadian Rockies of British Columbia has been a fossil hunters dream since its discovery in the first decade of the 20th century. It so confounded those that dug it up and subsequently studied it mistakenly identified its head as its tail while its spines turned out to be legs. But according to a new study that was published yesterday in the journal Nature, Hallucigenia sparsa is actually the ancestor to the nasty-looking slug-like creature with centipede-like legs somewhat oddly called the velvet worm.

Worm claws?

“The peculiar claws of Hallucigenia are a smoking gun that solves a long and heated debate in evolutionary biology,” said study researcher Martin Smith, an earth scientist at the University of Cambridge. That comment combined with some made by Javier Ortega-Hernandez, a paleobiologist at the University of Cambridge (also involved in the study) cast doubt on the evolutionary history of insects, spiders, and crustaceans.

Hallucigenia is not a nod to acid-dropping, pot-smoking basement dwellers of European academia, but the Cambrian era creature did confound researchers for some time in order to earn that distinction. While discovered in the 70s, it took, Lars Ramskold, then at the Swedish Museum of Natural History until 1992 to turn the fossil right-side up in order to best classify it.

“Even with the correct orientation, Hallucigenia has been regarded as problematic, because there are few features that connect it directly with living organisms,” Ortega-Hernandez told Live Science recently in an email interview with contributor Stephanie Pappas that led to a recent piece.

However, it still confounded researchers until they realized its “claws” firmly brought it into the worm family’s tree. Those claws resemble the chewing claws of today’s velvet worm.

Cambrian Explosion

“It’s often thought that modern animal groups arose fully formed during the Cambrian Explosion,” Smith said. “But evolution is a gradual process: Today’s complex anatomies emerged step by step, one feature at a time. By deciphering ‘in-between’ fossils like Hallucigenia, we can determine how different animal groups built up their modern body plans.”

While I’ll trust that Smith knows more about velvet worms, this thing looks like something that Han Solo once flew the Millennium Falcon into to escape capture by the Empire.

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