Time-calibrated phylogeny inferred using BEAST. Posterior probability (PP) values are indicated by node color. Node numbers next to nodes represent the divergent times. Purple bars indicate 95% credibility intervals of estimated node ages. The left in Roman numbers represents fossil calibration points. The primary species of study for this article are shaded red, including species of Loxoblemmus, Mitius, and Stephoblemmus. The blue letter is the type species of Stephoblemmus. The geological timescale is shown at the bottom (Ma = million years ago).