How Did Sea Plants Open and Close?

Scientists have stumbled on leaf fossils with holes in them where presumably a big hungry, cretaceous caterpillar has made a meal of them. These holes are symmetrical about the leaf's midline. Scientists think this is because when the animal bit into it, the leaf was closed. When it opened again, there was a hole in both surfaces. Emma Pomeroy commenting on that paper describing those findings this week in the journal Science Advances.