Follow Dec. 21, 2020 Among the great mysteries bedeviling science are dark matter (what is it?), death (do we have to?) and what fleas are. Meaning, where do they belong on the tree of life? Now that last conundrum has been put to bed by University of Bristol undergrad Erik Tihelka. They are scorpionflies, a distant cousin of the fly. Specifically, the closest living relatives of fleas are the scorpionfly family Nannochoristidae, “a rare group with only seven species native to the southern hemisphere,” the team wrote – New Zealand, southeast Australia, Tasmania and Chile. They aren’t...