Fossil preservation and the stratigraphic ranges of taxa
Fossil preservation and the stratigraphic ranges of taxa
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DOI：
10.1017/s0094837300016134
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发表时间：
1996-03-01
期刊：
影响因子：
2.7
通讯作者：
Raup, DM
中科院分区：
文献类型：
--
作者：
Foote, M;Raup, DM
化石记录的不完整性阻碍了对进化速率和模式的推断。在这里，我们得到真正的分类持续时间，保存概率，和观察到的分类范围之间的关系。我们使用这些关系来估计原始分布的分类持续时间，保存概率，和完整性（类群保存的比例），只考虑到观察到的范围。不需要分类群范围内出现的数据。当保存是随机的，并且持续时间的原始分布是指数分布时，持续时间，可重复性和完整性的推断是精确的。然而，合理的近似值是可能的，给出非指数的持续时间分布和时间和分类的变化。通过对上寒武统-下奥陶统三叶虫种、古生代海百合属、侏罗纪双壳类和新生代哺乳动物种的分析，得出以下结论：（一）仅从地层范围推断的保存概率与从地层空区分析推断的保存概率一致，后者可用。(2)而中位数持续时间的基础上观察到的范围的简单表格有偏见的地层分辨率，我们的估计中位数持续时间，灭绝率和完整性没有偏见。(3)哺乳动物物种的地质范围相对于双壳类物种的地质范围较短，这不能归因于保存潜力的差异。然而，我们不能排除分类学实践对这种差异的贡献。(4)在研究的群体中，完整性（物种[三叶虫，双壳类，哺乳动物]或属[海百合]保存的比例）范围从60%到90%。在较小的地理尺度上，对完整性的较高估计支持了先前的观点，即化石记录的不完整性更多地反映了含化石岩石的损失，而不是物种未能首先进入化石记录。
The incompleteness of the fossil record hinders the inference of evolutionary rates and patterns. Here, we derive relationships among true taxonomic durations, preservation probability, and observed taxonomic ranges. We use these relationships to estimate original distributions of taxonomic durations, preservation probability, and completeness (proportion of taxa preserved), given only the observed ranges. No data on occurrences within the ranges of taxa are required. When preservation is random and the original distribution of durations is exponential, the inference of durations, preservability, and completeness is exact. However, reasonable approximations are possible given non-exponential duration distributions and temporal and taxonomic variation in preservability. Thus, the approaches we describe have great potential in studies of taphonomy, evolutionary rates and patterns, and genealogy.Analyses of Upper Cambrian-Lower Ordovician trilobite species, Paleozoic crinoid genera, Jurassic bivalve species, and Cenozoic mammal species yield the following results: (1) The preservation probability inferred from stratigraphic ranges alone agrees with that inferred from the analysis of stratigraphic gaps when data on the latter are available. (2) Whereas median durations based on simple tabulations of observed ranges are biased by stratigraphic resolution, our estimates of median duration, extinction rate, and completeness are not biased. (3) The shorter geologic ranges of mammalian species relative to those of bivalves cannot be attributed to a difference in preservation potential. However, we cannot rule out the contribution of taxonomic practice to this difference. (4) In the groups studied, completeness (proportion of species [trilobites, bivalves, mammals] or genera [crinoids] preserved) ranges from 60% to 90%. The higher estimates of completeness at smaller geographic scales support previous suggestions that the incompleteness of the fossil record reflects loss of fossiliferous rock more than failure of species to enter the fossil record in the first place.