Biogeography of Chilean millipedes. a Bell-shaped latitudinal diversity gradient. The second-degree polynomial function (segmented line) reveals that millipede diversity peaks in central Chile and then decreases significantly towards northern and southern Chile. b Latitudinal range size of millipede species. All species were categorized as micro-range endemics because they all have latitudinal ranges of less than 1,000 km (with 78% of species exhibiting latitudinal ranges of only ~222 km).