Animal-Teeth Maps Used to Track Environment Changes

(CN) – Using charts of digitally rendered models of present-day animal teeth, researchers have created a new way for scientists to learn about the diets of extinct animals from fossil records in hopes of learning how species evolved in response to environmental changes.

Led by Silvia Pineda-Munoz, a paleontologist at the Smithsonian’s National Museum of Natural History, researchers developed a more informative and accurate method for comparing nuances of the shape of teeth from fossil records to those of existing animals.

The technique requires a three-dimensional scan of a set of teeth, which creates a digital model resembling a topographic map of the Earth’s surface. Geographic information system technology is used to analyze the map and present a mathematical description of how certain key features affect how teeth process food.

teeth-map-cheetahScientists can use nuanced models to compare the surface of an animal’s teeth with those of more than 130 present-day mammals in eight different dietary categories.

“The new method gives researchers a way to measure changes that arose as animals adapted to environments altered by mass extinctions or major climate shifts,” Pineda-Munoz said. “That in turn can help researchers and conservations predict and plan for such events in the future.”

The study was published Monday in the journal Methods in Ecology and Evolution.

Foods that require a lot of chewing before being digested, like tough vegetation, are associated with more complex teeth arrangement and conditioning, according to Pineda-Munoz.

Different features reflected different diets. Pandas have complex teeth that can crush hard leaves, while hyenas have scissor-like teeth that are ideal for tearing meat.

“Those categories give detailed information about an animal’s primary food source, including plants, meat, fruits, grains, insects, fungus or tree saps, with an additional ‘generalist’ diet category,” Pineda-Munoz said.

The maps were used to create a database recording six measurable features of tooth topology – the study of geometric properties and spatial relations – for the top and bottom sets of teeth from present-day mammals.

Using the team’s method, researchers can scan teeth from fossil records and analyze how their features compare to the teeth of modern animals with known diets, similar to how websites use algorithms to predict what similar content a user will enjoy based on his past selections.

“It’s a method that looks at evolutionary change,” Pineda-Munoz said. “It tells you not just what the animal was eating at this point in time, but what the animal was adapted to eating.