Keep It Simple, Sauropods
“The diet of extinct dinosaurs was incredibly varied, spanning tiny meat-eaters to massive plant-eaters,” says Dr. Melstrom. “Our research sheds light on the range of adaptations that allowed so many plant-eaters to live alongside one another.”
Using computerized tomography (CT) and microCT scanning, Dr. Melstrom and his colleagues made 3D models of specimens from around the globe, capturing the great diversity of tooth complexity in Late Jurassic dinosaurs.
“This whole project was conducted during the pandemic. Instead of traveling the world to gather data, we relied on researchers who had made their data available to other scientists, as well as the incredible collections here at NHM. I think this project really demonstrates the importance of sharing information, it can lead to new discoveries even during a pandemic,” says Dr. Melstrom.
They converted the toothy hills and valleys of dinosaur teeth into numbers, quantifying tooth complexity between the three groups of dinosaurs: meat-eating theropods, plant-eating ornithischians, and similarly herbivorous sauropods.
What they found was an entirely new evolutionary strategy to handle a plant-based diet 150 million years ago. While meat-eating dinosaurs had sharp simple teeth expected for carnivores, and ornithischians had the more complex teeth similar to herbivores living today, sauropods had very simple teeth, unlike any other known herbivores extinct or living.
In sauropods, they found that the more complex the tooth, the more slowly teeth were replaced, a correlation that demonstrates that tooth replacement rate is related to tooth complexity, unlike any other known animals. More specifically, diplodocoids like Apatosaurus and Diplodocus exhibited incredibly fast replacement rates and simple teeth, possibly allowing them to eat different foods from the other group of sauropods, macronarians like ??Brachiosaurus, which had more complex teeth.
Simple teeth would have made sense for sauropods’ long necks. Smaller teeth built to be lost weigh less than the tougher teeth of all other herbivores, which helps lighten the skull at the end of those long necks. The peculiar tooth replacement pattern meant these sauropods could focus on plant food other dinosaurs and non-dinosaur plant-eaters passed by.
“Time and time again, the fossil record shows us that there isn’t one solution to evolutionary problems. For sauropods, when it comes to eating tough plants, the simplest solution was the best,” says Dr. Melstrom.
— Read on www.sciencedaily.com/releases/2021/11/211111080404.htm