Plant-eating dinosaur had huge chisel-shaped teeth

The teeth of the upper and lower jaws came into contact and formed a self-sharpening surface. Those in the maxilla grew in a staggered pattern, with every other tooth in the jaw the same age and either younger or older than adjacent teeth. This ensured that all eight teeth wouldn’t be shed at the same time.

Other rhabdodontids have superficially puffin-shaped faces with tall and narrow snouts. The back-ends of their skulls are extremely wide, housing powerful jaw-closing muscles. They were bipedal herbivores, capable of running on two feet at moderately fast speeds. Matheronodon differs from other rhabdodontids not only in the small number of large teeth, but the smaller area for attachment to the beak, maybe meaning a blunter snout than its relatives.

Although Matheronodon takes its teeth to an extreme, other rhabdodontids have similar, if smaller, chisel-like teeth that allowed their jaws to work like scissors. This is quite different from the dental batteries that evolved in their relatives the hadrosaurs, or “duck-billed” dinosaurs. Their jaws were filled with hundreds of small, closely-packed teeth that were locked together in a battery, forming a sort of super-tooth with a huge grinding surface. Instead of slicing like the rhabdodontids, the hadrosaurs ground and crushed plant material.

Godefroit and colleagues suggest that Matheronodon may have preferentially fed on plants with especially fibrous leaves like palmettos and other palm-like plants, using its scissor-like jaws to slice the tough material. On the other hand, hadrosaurs appear to have largely eaten conifers, grinding the needles and twigs in their dental batteries.

Matheronodon lived about 10 million years before the end of the Age of Dinosaurs. At the time, Europe was made up of many large islands, looking quite like modern Indonesia. During the last few million years of the Cretaceous, hadrosaurs first reached the European islands, replacing rhabdodontids in many areas. Godefroit and colleagues suggest that the replacement may be related to a change in plant life, but more information is needed to know with certainty. Further discoveries will surely tell us more about Matheronodon and the other rhabdodontids, including information on their evolution, diet, and interaction with hadrosaurs.

Read the original research in Scientific Reports.

Pete
Buchholz

Senior Writer

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