A second species of the pill millipede genus Wesener, 2012 (Diplopoda, Glomerida) from the Great Smoky Mountains, USA.

We describe a second species of Wesener, 2012, a genus of pill millipede endemic to the southern Appalachians, based on morphological and molecular evidence. The fauna of Glomerida in America is characterized by its low diversity, and is only the fifth species of the order known from the eastern United States. Our phylogenetic analyses based on COI sequences recover a tentatively monophyletic lineage including both eastern American genera Cook, 1896 and , with a common ancestor in the Late Cretaceous to Mid Eocene and extant diversity within genera dating back to the Miocene. Our results suggest that the observed low diversity of the group in the eastern US is likely caused by extinction events, but it is also possible that new species are yet to be found. We provide new records for Wesener, 2012, Cook, 1896 and Hoffman, 1950; the latter is here reported for the first time from South Carolina. We also present DNA barcoding data for all species of Glomerida present in the US that are not yet publicly available.