"What I think is very neat about this project is that it provides a beautiful example of evolutionary tinkering or 'bricolage,'" said Coates, a professor of biology at the University of Chicago. "We have a combination of experimental data with paleontological evidence to show how these fishes co-opted a preexisting program for manufacturing teeth to make a new device that is essential for reproduction."
[…]
The bizarre path from a mouth full of teeth to forehead
teeth used for mating demonstrates the impressive flexibility of evolution, the researchers say, always ready to repurpose structures for strange and unexpected new uses.