Figure 7. Likelihood function for the time of origin of Mesonychia, calculated as shown in Table 4 (but with a 0.0001 increment of origination volume). Note that maximum likelihood here (L = 1) corresponds to the time t = 63 Ma when the fossil record of Mesonychia begins. L = 0.05 (the critical likelihood l employed here) when t is about 66.7 Ma.