Atopodentatus, on the other hand, is a bit of mystery. The first specimen when described in 2014 had been crushed laterally as it fossilized, so it was reconstructed as pictured here with the upper jaw having a zipper-like formation. They figured it was probably some sort of really unusual filter feeder.
Then two more specimens in 2016 showed that actually the mouth was more a wide flattened thing shaped like a vacuum cleaner. They figure it ate algae and seaweed, scraping it off rocks like modern day marine iguanas do, but the teeth are needle-like and jut forward, so it's not clear how they were used exactly.
