The oldest pill millipede fossil
The first new fossil pill millipede, order Glomerida, description in more than 150 years is based on two specimens, one male and one female, found in Baltic amber. Both specimens were studied with light- and micro-CT technology, allowing a detailed reconstruction of the posterior telopods and numerous other morphological characters. Based on these characters, the specimens can be securely placed in the megadiverse, mainly Asiatic genus Hyleoglomeris Verhoeff, 1910 as a new species, Hyleoglomeris groehni n. sp. The species H. groehni n. sp. is the oldest and only known fossil member of the Glomerida that is sufficiently described to allow for placement in a family or genus. The discovery of a fossil Hyleoglomeris in Baltic amber has biogeographic implications as the genus is now speciose in Asia, with the nearest relatives found in the Caucasus and some caves in Serbia and Greece. With the discovery of a fossil European Hyleoglomeris species, the cave Hyleoglomeris species are interpreted as relicts, surviving underground as living witnesses of a different time when Hyleoglomeris was still extant in Europe. Other cave Glomerida in Europe, as well as morphologically aberrant pill millipede species endemic to the Canary Islands, should be checked for potential placement in Hyleoglomeris.