 In Figure 2, we have taxa 2, 6, 8, 10. The minimum spanning path connecting each requires 28 character changes and thus its PD is 28. As Maclaurin and Sterelny note, this assumes that we have an adequate sample of character traits and given that many are molecular they do not tell us much about phenotypes (Maclaurin &amp; Sterelny 2008: 141). Thus, they suggest we stick with local morphospaces.