This Spiky Creature with No Anus Isn’t Our Ancestor After All

Scientists used to think that a tiny sack-like creature that lived 500 million years ago could be an early ancestor of all vertebrates, including humans. But new research revealed that it’s likely related to insects and crabs instead. An international team created a 3D model based on X-rays of hundreds of microscopic fossils found in China. The creature, called Saccorhytus coronarius, looks a bit like an angry Minion, with a huge gaping mouth.

3D model of Saccorhytus, an early animal with a large mouth and spines all over it

Saccorhytus is covered in spines. And it’s those spines that led to the ancestral mystery in the first place. Scientists originally thought the ones around the creature’s mouth were early versions of gills. If that was the case, it likely evolved into fish, which then branched off into all vertebrates, including humans. But the new research shows the holes around the mouth are actually broken off spines similar to those on the rest of Saccorhytus‘s body. That, along with other clues, leads the science team to include them with invertebrates like arthropods, which includes insects, spiders, and crustaceans.

The scientists published their results in the prestigious peer-reviewed journal Nature. We saw the news on Boing Boing. And also learned more in press releases from the University of Bristol and Chinese Academy of Sciences. Many outlets picked up the story five years ago, when the link to humans was first made. The video below is a good explainer for why scientists at the time thought Sacchorytus might be an early human ancestor.

All of the artistic renderings of this tiny creature are a bit unnerving. It may not be the creepiest Minion we’ve ever seen, but it’s still not something I want to look at for too long. Especially with the added detail that Saccorhytus has no anus, meaning it poops through that big gaping mouth as well.  

Melissa is Nerdist’s science & technology staff writer. She also moderates “science of” panels at conventions and co-hosts Star Warsologies, a podcast about science and Star Wars. Follow her on Twitter @melissatruth. 

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