Figure 3 in Aedeagus evolution promotes speciation? A primary pattern in rove beetle phylogeny

Figure 3. Plotting Paramere-to-Median-lobe Index (PM Index) and the number of species of the selected genera (Y axis) with the divergence time (X axis) estimated. PM Index variations along with divergence time (a, c); species number variations along with evolutionary time (b, d). The abbreviation of geological ages are as follows: Jur—Jurassic; Cre—Cretaceous; Pal—Paleocene; Eoc— Eocene; Oli—Oligocene; Mio—Miocene; Pli—Pliocene.