However, despite learning much about scarce yellow sally, the scientists still have no idea how it got its name.

The tiny river fly, known as scarce yellow sally, was thought to have died out a few decades ago.

Just a few years ago, it seemed like the scarce yellow sally stonefly had gone locally extinct.

Using traditional and eDNA sampling across 12 locations on the River Dee, Mr. Davy-Bowker and his colleagues documented six sites with traces of the scarce yellow sally stonefly, according to findings published last fall.

In 2017, after years of using eDNA to study octopuses and crayfish, Mr. Mauvisseau turned his attention to the scarce yellow sally stonefly.