Time-calibrated phylogenetic tree of USC butterflies constructed from all nuclear genes. Tree branches are colored by relative substitution rate from cyan (slow evolving) through dark-blue and magenta to red (fast evolving). The time scale is in Mya. Species are arranged clockwise starting from the time-scale. A ring colored by butterfly family sectors is placed at the Cretaceous-Paleogene (K-Pg) boundary. Bootstrap support values are marked as color-coded dots on the tree nodes. Clusters of explosive radiation are highlighted in lime-green. The names of families and major phylogenetic lineages discussed in the text are given by their branches. Species names are highlighted by family and shown in two layers. Names in the inner layer are connected to the corresponding tree leaves with dots, and they label every other leaf in the tree. Each name in the outer layer is placed in between and connected by dots to two names of the inner layer, and it refers to the leaf in between the leaves indicated by these two names of the inner layer. Butterfly images represent all major phylogenetic lineages and numbers in green font associate specimens (a number is mostly above a specimen) with their names in the tree (numbers are either before or after the species names for the left and right halves of the tree, respectively).