The butterfly used to live only on the San Francisco Peninsula. But by around 1941, less than a century after its formal scientific description in the 1850s, the gossamer-winged butterfly had vanished. (From 2021)
. There are insects that went extinct earlier, like the Rocky Mountain locust , that scientists have strong suspicions that humans were to blame for the extinction. But for this butterfly, there was no question at the time.
But it’s long been unclear if the Xerces blue butterfly was its own species, or simply an isolated population of another, more widespread species of blue butterfly, says Corrie Moreau, an entomologist at Cornell University. Scientists analyzed DNA from a specimen in the collection of Xerces blue butterflies at Chicago’s Field Museum to reveal that the extinct insect was a distinct species.Using the genes and the “mitogenomes,” the researchers crafted an evolutionary tree, showing how all of the butterfly species are related to each other. The extinct Xerces blue butterfly was genetically distinct, thus warranting classification as a species, the team found.