A good number of millipede species are well adapted to live in caves and so is our new species which was found in a cave in Southern Thailand. Its scientific name was chosen to indicate that it has the largest body size of all species known in the genus Trachyjulus.
For the experts: A new, giant species of Trachyjulus from a cave in southern Thailand is described, illustrated, and compared to morphologically closely related taxa. This new species, T. magnus sp. nov., is much larger than all other congeners and looks especially similar to the grossly sympatric T. unciger Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2012, which is widespread in southern Thailand. Phylogenetic trees, both rooted and unrooted, based on a concatenated dataset of the COI and 28S genes of nine species of Cambalopsidae (Trachyjulus, Glyphiulus, and Plusioglyphiulus), strongly support the monophyly of Trachyjulus and a clear-cut divergence between T. magnus sp. nov. and T. unciger in revealing very high average p-distances of the COI gene (20.80–23.62%).