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Scientists Use Play-Doh to Understand the Feeding Habits of an Ancient Reptile

The hammerhead-shaped, zipper-teethed mouth of the Atopentatus was used to scrape algae off rocks and slurp it up.
May 8, 2016, 8:47pm
Image: Y. Chen, IVPP.

The ancient ocean was replete with fearsome beasts. There was the megalodon, the largest shark that ever lived. The giant lizard plesiosaurs roamed around with razor sharp teeth devouring prey. The Thalattoarchon swam like a sea turtle and preyed like a crocodile, measuring more than 28 feet long. Then there was "Predator X," a 50 foot beast with the jaw strength of four T. Rexes.

The Atopodentatus unicus was none of these things. It was originally found in 2014 and thought to be an amphibious predator of small animals and a general filter feeder. But two newly found skulls, reported this week in the journal Scientific Advances, instead paint the picture of a 10-foot animal that swam the oceans in search of plants on the seafloor. While it had a hammerhead-like facial shape, it was all the better to find just the right algae or other sea floor goodies.


The large marine reptile is one of, if not THE earliest marine reptile specimens ever found. The fossil dates to just after the Permian-Triassic extinction event around 252 million years ago, which saw as much as 96 percent of all species on Earth at the time go kaput. The Atopodentatus was remarkably well adapted to the ocean depths, with a series of needle shaped teeth. Rather than using these to pierce the skins of prey, though, they instead aligned to become precision filter feeders, which looked, in the end, like a comb.

Image: Olivier Rieppel, The Field Museum

So how do you take a bunch of sharp, needle-like teeth and make the distinction that this was no fearsome carnivore? The researchers from Institute of Vertebrate Paleontology and Paleoanthropology, the Field Museum in Chicago, the National Museums Scotland, and the Centre of China Geological Survey used Play-Doh. Yes, the stuff you either used to make clay dinosaurs or resisted the temptation to eat as a child.

They reconstructed a simple clay mouth, according to the BBC, then set a bunch of toothpicks in it. From there, they were able to get a better idea of the inner workings of its jaw. The sharp teeth helped dislodge some of the plant matter from the sea floor. The teeth on the top and bottom jaw interspersed in such a way as to make a fine sieve once this matter was collected. From there, it would move along to its next feeding spot.

The researchers note that this is the earliest marine herbivore ever found, and appears to be a separate lineage from the Henodus, a turtle-like reptile that evolved on the other end of the Triassic, some 20 million years later.