When the fruit bat Pteropus allenorum was finally described by scientists, it was already extinct. One specimen of the bat was shot in Samoa in 1856, skinned, stored in alcohol, and shipped to the United States. It spent the next 153 years, inconspicuous and ignored, on a shelf in the Academy of Natural Sciences in Drexel University. When bat specialist Kristofer Helgen visited the museum, he immediately recognised that it was a new species. Sadly, it was too late. There are no fruit bats in Samoa nowadays, so the jar on the shelf represents our only encounter with this now-extinct animal.
The fruit bat’s story isn’t an original one. The beetle Meligethes salvan was collected from the Italian Alps in 1912 and sat in Frankfurt’s Senckenberg Museum until it was described in 2003. In the intervening time, the valley from which it came had been almost entirely destroyed in the process of building a hydroelectric power plant. Biologists searched in the nearby valleys but couldn’t find it. The beetle may be extinct.
These examples show that the shelves and drawers of the world’s museums are among the planet’s most diverse habitats—ecosystems brimming with different species, many of which have never been seen before.
People often think that discoveries are made when biologists see new species in the field, and immediately recognise them as such. That’s largely not true. Field biologists often collect their specimens en masse, taking them back to their respective institutions, and keeping them in storage until they get a chance to peer at them properly. This means that many of the planet’s new species are sitting pretty in jars and drawers, gathering dust while they wait to be formally described.
How long is this shelf life? For the bat, it was 153 years, and for the beetle, 92. On average, it’s around 21 years, according to a new study from Benoît Fontaine from the Natural History of Museum in Paris.