Scientists discover what was on the menu of the first dinosaurs

A team of University of Bristol paleobiologists believe that the earliest dinosaurs were omnivorous.

By looking at the tooth shapes of the earliest dinosaurs, experts were able to compare them to living lizards and their diet. The ancestors of our famous long-necked herbivores, such as Diplodocus, ate meat, according to their findings. Their success is likely due to their ability to change their diet early on.

The earliest dinosaurs were smaller than their later relatives and they were in the shadow of crocodiles. It's not known how diverse the dinosaurs were in terms of diet and ecology, but they must have been able to adapt to the mass extinction of the Dinosaurs.

Dinosaurs show an interesting diversity of skull and tooth shapes soon after their origin. Paleontologists suspected that different species were experimenting with different types of diet. They compared them to lizards and tried to figure out what they ate by looking at their teeth.

To investigate this, we applied a set of computational methods to quantify the shape and function of the teeth of early dinosaurs and compare them to living lizards that have different diet. They used engineering software to model their tooth shapes.

The study used a battery of methods to quantify how similar early dinosaurs were to modern animals. The teeth of theropod dinosaurs were similar to those of monitor lizards. The denticulated teeth of ornithischians and sauropodomorphs are similar to those of omnivores and herbivores.

Machine learning models are being used to classify the earliest dinosaurs in different diet categories based on their tooth shape and mechanics. The teeth of the Bristol dinosaur were well adapted for the diet of plants.

The ornithischians, the group that includes the horned dinosaurs, the armored ankylosaurs and the duck-billed dinosaurs, started off as omnivores. The earliest sauropodomorphs, ancestors of the veggie long-necked sauropods like Diplodocus, were also meat eaters. It has been shown that herbivory was not ancestral for any of these two groups, and that the diet of early dinosaurs was quite diverse.

One of the things that made the first dinosaurs special is that they evolved different diet throughout the Triassic, and we think this may have been key for their evolutionary and ecological success.

Dinosaurs ruled the land for 66 million years before they died. There were giant veggie groups like the long-necked sauropods and meat-eating species. The first definitive dinosaurs appeared over 200 million years ago, but their origins were much more humble.

Antonio Ballell has information on dental form and function in dinosaurs. www.science.org/

Journal information: Science Advances