The scales may also provide insight into the early evolution of the insect’s tubelike tongue, or proboscis, which the authors suggest evolved tens of millions of years before nectar-rich flowers existed.

Mr. van Eldijk made the discovery while working with Bas van de Schootbrugge, a geoscientist at Utrecht University, on a project to investigate ancient pollen in the fossil record, particularly during the mass extinction about 200 million years ago that ended the Triassic Period and ushered in the Jurassic. For that project, the team drilled deep below northern Germany in what was once an ancient lagoon to collect sediment from the time of the extinction event. They then dissolved the rock in chemicals that eat away any material that was not organic, leaving pollen samples behind in a black goop which the team could search through, drop by drop.

But in analyzing the murky solution they stumbled upon a new mystery: several unknown scales were left behind in the gunk. The team soon discovered that the scales belonged to long extinct relatives of modern butterflies and moths. Mr. van Eldijk was tasked with fishing out more, and for that job he was given a dissection probe with a single nostril hair.

“The nose hair has just the right length and springiness for getting a pollen grain, or in this case the butterfly scale, to adhere to it,” Mr. van Eldijk said. “I was just provided these by my professor, I don’t know whose nose hair it was. It’s probably best not to ask.”