Crocodiles — and their plant-eating ancestors — have thin tooth enamel, a trait that is in stark contrast to humans and other hard-biting species, according to new research.
Sellers et al found regardless of tooth position, age, or diet, crocodiles do not have thick tooth enamel. Image credit: Pexels.
“Once we unlock genetically how crocodiles and other non-mammals do this, maybe new teeth can be bioengineered for people,” said Brianne Schmiegelow, a student at University of Missouri-Kansas City.
“Instead of using fillers such as crowns, people could instead grow new teeth when they need to replace their worn out chompers.”
Schmiegelow and colleagues used a 3D X-ray scanner to measure the thickness of tooth enamel in crocodiles.
The researchers found regardless of tooth position — incisor, canine, molar — age or diet, crocodiles do not have thick tooth enamel.
They also studied all available data on dinosaur teeth, and found that the data nearly matched what they were seeing in crocodiles.
For instance, a Tyrannosaurus rex had the same enamel thickness as a crocodile, and can also bite extremely hard.
CT scan of a crocodile tooth. Image credit: University of Missouri.
“Crocodiles bite really hard, so we were curious if they have teeth that correspondingly withstand those forces — tough teeth to match a tough bite,” said Dr. Kaleb Sellers, a postdoctoral researcher at the University of Missouri.
“We found that they don’t have tough teeth, and we think it’s because they replace their teeth like most other non-mammal animals. That made us wonder if other animals — even prehistoric — had similar issues.”
The team now plans to study tooth replacement and the timing of teeth growth in crocodiles and other animals such as dinosaurs.
“Enamel takes a long time to build, so it’s not something animals will do off-the-cuff, so to speak,” said Dr. Casey Holliday, also from the University of Missouri.
“It presents us with an interesting puzzle. If ancient crocodiles were chewing plants, did their new teeth already have the correct architecture — dimples and facets — to allow for this chewing? The findings here have paved the way for exploring this mystery with future research.”
The study was published in the Journal of Zoology.
_____
K.C. Sellers et al. The significance of enamel thickness in the teeth of Alligator mississippiensis and its diversity among crocodyliforms. Journal of Zoology, published online July 1, 2019; doi: 10.1111/jzo.12707
