Does likelihood minimize stratigraphic gaps?
A parsimony tree of fossil and extant crocodiles1 implied a sum of gaps totaling 743 million years (Ma). This debt distributed over 62 taxa implies a sampling intensity (R) of 0.022 finds per million years2. The stratigraphic ranges of the analyzed taxa reveal that the vast majority of taxa are known from single localities, suggesting a low value of R (ref. 3). In fact, the most likely R given these data (0.011 finds per Ma) 4 is lower than implied by the parsimony tree. As a result, trees positing >1200 Ma of gaps are considered more likely by stratigraphic data than is the parsimony tree (Fig. 1a). Because ln L [R = 0.022|ranges] = -0.2, stratigraphy would not reject the parsimony tree. Note that a tree positing no gaps (and a minimum R = 0.97) has a log likelihood of -22. Stratigraphic data would reject such a tree. Figure 1 Log likelihoods of stratigraphic debts. High resolution image and legend (7k) Good records still posit gaps Many fossil hyaenids are known from numerous localit
