Foote M, Hunter J P, Janis C M, Sepkoski J J
Department of the Geophysical Sciences, University of Chicago, 5734 South Ellis Avenue, Chicago, IL 60637, USA.
Science. 1999 Feb 26;283(5406):1310-4. doi: 10.1126/science.283.5406.1310.
Some molecular clock estimates of divergence times of taxonomic groups undergoing evolutionary radiation are much older than the groups' first observed fossil record. Mathematical models of branching evolution are used to estimate the maximal rate of fossil preservation consistent with a postulated missing history, given the sum of species durations implied by early origins under a range of species origination and extinction rates. The plausibility of postulated divergence times depends on origination, extinction, and preservation rates estimated from the fossil record. For eutherian mammals, this approach suggests that it is unlikely that many modern orders arose much earlier than their oldest fossil records.
一些对经历进化辐射的分类群分歧时间的分子钟估计，比这些类群首次被观测到的化石记录要古老得多。分支进化的数学模型被用于估计与假定的缺失历史相一致的最大化石保存率，前提是在一系列物种起源和灭绝率下，早期起源所隐含的物种持续时间总和。假定分歧时间的合理性取决于从化石记录中估计出的起源、灭绝和保存率。对于真兽类哺乳动物来说，这种方法表明许多现代目不太可能比它们最古老的化石记录早很多出现。
