Reptile enthusiasts are often stereotyped as obsessed with teeth. For Prof. Domenic D’Amore, biology, Daemon College, this seems to hold true. In a talk Monday evening, D’Amore captivated the room with his research on the world of reptilian jaws — from dinosaurs to lizards.
D’Amore was originally interested in the function of dinosaur teeth, which led him to study the unique dental structure of raptors. The flat, sweeping curves and serrated edges that once lined the jaw of these predators have largely been lost to evolution and extinction, D’Amore said.
However, similar teeth are observed in Komodo Dragons, a type of lizards with long tails, strong and agile necks and the subject of research in D’Amore’s doctoral dissertation, which focused on these lizard’s tooth structure and function.
D’Amore then turned his research to Nile Monitors. The size and shape of the teeth of these large, predatory lizards change as they age: Older monitors have more bulbous and less needle-like teeth than juveniles. However, while this change was casually known, it was never formally studied with mathematical precision.
“I never actually measured teeth, and the only way we’re going to solve the problem about understanding reptile teeth is if we actually quantify them,” D’Amore said.
Utilizing tpsDig, a landmark scaling software, D’Amore was able to map out the shape and size of each Nile Monitor tooth on a coordinate plane. This new measuring method allowed him to contribute numeric data to an area in which qualitative descriptions were coming up short. D’Amore then broadened the software’s use to crocodilians and snakes, and his data revealed illuminating patterns.
“I wanted to define heterodonty — which literally means difference in teeth — as a degree of difference,” D’Amore said. “Now, if something is homodont, you would expect them to have the same size and the same shape. What I wanted to look at was can I look at differences in size and shape separately?”
D’Amore’s findings include a litany of differences in tooth size and shape between and within species of reptiles. These differences quantifiably confirm qualitative theories that can help explain animal adaptations and behaviors.
“We are able to isolate differences between the species based on their teeth,” D’Amore said. “We can say that a smaller snake has shorter thicker teeth and a larger snake tends to have larger, thinner, more needle-like teeth.”
Further implications of D’Amore’s work come full circle when considering what originally drove him to this field. If the models and methods he is using can confirm knowledge about present day reptilians, they should also help us understand the ecology and biology of extinct species using just their fossil teeth.
According to D’Amore, if there are gaps in the data, there are always new and unexpected ways to fill them.
“The big problem is that tooth structure and function [are] poorly understood in reptiles. Because of the lack of dental categories, the assumption is made that all the teeth in the mouth look the same,” D’Amore said. “This dismissive attitude is something I’d like to reduce, if not entirely get rid of.”