File:Robust-Time-Estimation-Reconciles-Views-of-the-Antiquity-of-Placental-Mammals-pone.0000384.g003.jpg

English: The blue squares show the rate of the appearance of new species based on the fossil record [adapted from 3]. At present, such quantitative data are limited to the well-studied North American record. The red circles represent the chronological distribution of node density (or splits) on the MVS-FIR tree (Figure 1A). The green triangles represent split frequency on the ML-FLOG tree (Figure 1B). The node density is given by the number of nodes in an 8 myr sliding window. A scaling constant for the molecular frequencies was calculated via a least-squares fit to the fossil data in the period 85–50 mya.