The Oldest Teeth on Earth

These teeth are smaller than one millimeter. Photo: Bryan Shirley

We’re all aware of global warming; the extreme temperatures in Erlangen this summer were enough of a reminder! Although the world’s current warming crisis is the result of human industrialization, the Earth has passed through other periods of massive climate change over the course of its 4.5 billion year history. But how do we know this? We can hardly trust the TV weatherman to accurately predict rain tomorrow, so how can we know what the climate was doing millions or billions of years ago?

For the answer to that question, says international student Bryan Shirley, we just need to look at a set of teeth.

Shirley recently completed his Master’s in micropalaeontology and paleoclimatology with the submission of his thesis on a really, really, really old set of animal teeth. The teeth, which are around 425 million years old, were discovered in Sweden and belong to the conodont, an eel-like marine creature from the late Silurian period, about 7 times older than the dinosaurs. Indeed, they’re the oldest teeth ever discovered from any form of life on Earth.

Shirley had been working on his Master’s at the University of Lille in Northern France when one of his lecturers connected him with FAU to study the teeth. His specific goal was to examine the deformations in the teeth to determine what had caused those deformations, and to thereby learn more about how the teeth grew and about the conodonts‘ way of life.

Bryan Shirley

Shirley, who comes from Ireland where he did his Bachelor’s in Earth and Ocean Science, has been especially interested in palaeontology, geology, and micropalaeontology, which he says is basically the study of very small fossils to determine past climate shifts and other changes. Small indeed: the teeth he studied are smaller than one millimeter! Shirley used microscopic imaging to look at the layers of growth within the teeth.

The teeth of the conodont are especially unique and worthy of study because they are actually able to repair their own teeth, which would sometimes break while the animals were eating. Among Shirley’s major findings was the fact that this repair process doesn’t always work out correctly and abnormal growth can occur, although such abnomalities did not seem to impact the animals‘ quality of life.

This winter, Shirley will continue his research of the conodonts at FAU for his PhD, hoping to discover more about the ecology of the animals‘ habitats. He might learn, for example, if the conodonts had begun breaking their teeth more frequently due to their prey evolving harder shells, which could in turn shed more light on the evolution of other shells, bones, and scales. Good luck, Bryan!

Keels Mad