An unexpected discovery: the pill millipedes of Mallorca and the Spanish Mediterranean

Pill millipedes not yet known for Mallorca

The millipede fauna of the island of Mallorca is actually relatively well researched. So we were all the more surprised when we received tourist photos from Mallorca with a request for identification, showing a pill millipede (Glomerida). Pill millipedes are not yet known for Mallorca. The Alexander Koenig Society (AKG) https://bonn.leibniz-lib.de/de/mitwirken/alexander-koenig-gesellschaft.html gave us a mini-grant and a collection permit for the remote area in the north of Mallorca was quickly applied for. The area is difficult to access, and in recent years tourists have regularly had to be rescued from the narrow rocky valleys after rainfall. Fortunately, our former doctoral student Leif Moritz is a hiker and free climber. After painstaking collecting, a few of the millipedes were discovered and analysed morphologically and genetically. Interestingly, the closest known relatives of the species endemic to Mallorca are millipedes, which are now only found in a few caves on the Spanish mainland. These so-called troglobionts have reduced their protective armour to such an extent that they appear glassy and transparent due to the lack of predators and energy conservation. The species from Mallorca, which is yet to be described, has normal armour. The common ancestors of the Spanish cave millipedes and the species from Mallorca must have lived several million years ago.