Fearsome Dinosaur-Age "Hammerhead" Reptile Ate... Plants?

The filter-feeding reptile's fossilized jaw was discovered in southwest China in 2014. Photo by Institute of Vertebrate Paleontology and Paleoanthropology/Chinese Academy of Sciences

With a maw like a vacuum cleaner, Atopodentatus unicus lived 242 million years ago, following the Permian-Triassic extinction event. It also, as researchers publishing in Science Advances claim, is the earliest example of an herbivorous marine reptile.

The research was a collaboration between the Institute of Vertebrate Paleontology and Paleoanthropology, the Field Museum of Natural History, Wuhan Centre of China Geological Survey, and the National Museum of Scotland.

According to National Geographic, the first specimen of the species was discovered in 2014. Found in southwestern China, the specimen measured close to three meters-long, with a mouth cock-full of needle-like teeth.

“Atopodentatus, about (2.75 meters) long, lived in a shallow sea in China’s Yunnan Province alongside fish and other marine reptiles,” Wuhan Centre of China Geological Survey’s Cheng Long said in a statement. “When thinking of hammerhead creatures, sharks may come to mind. But Atopodentatus’ hammerhead feature differed in location and function from sharks, whose eyes are on the end of lateral extensions on their head.”

The two new specimens that the Science Advances study is based on were dug up from the Middle Triassic Guanling Formation of China’s Luoping County, located in the Yunnan Province. According to the researchers, the creature’s hammerhead jaw had peg-like teeth along the edge, with the needle-like teeth located further into its mouth.

“The evidence indicates a novel feeding mechanism wherein the chisel-shaped teeth were used to scrape algae off the substrate, and the plant matter that was loosened was filtered from the water column through the more posteriorly positioned tooth mesh,” the researchers wrote.

According to study co-author Olivier Rieppel, of the Field Museum of Natural History, the feeding method Atopodentatus unicus employed was similar to how baleen whales filter-feed.

The species predates other herbivorous, filter-feeding animals by about 8 million years.

Provided by National Geographic