Sterli Juliana, Pol Diego, Laurin Michel
CONICET-Museo Paleontológico Egidio Feruglio, Av. Fontana 140, 9100 Trelew, Chubut Province, Argentina.
UMR 7207, CNRS/MNHN/UPMC, Muséum National d'Histoire Naturelle, Batiment de Géologie, Case postale 48, 43 rue Buffon, F-75231 Paris Cedex 05, France.
Cladistics. 2013 Jun;29(3):233-246. doi: 10.1111/j.1096-0031.2012.00425.x. Epub 2012 Sep 10.
Methods improving the performance of molecular dating of divergence time of clades have improved dramatically in recent years. The calibration of molecular dating using the first appearance of a clade in the fossil record is a crucial step towards inferring the minimal diversification time of various groups and the choice of extinct taxa can strongly influence the molecular dates. Here, we evaluate the uncertainty on the phylogenetic position of extinct taxa through non-parametric bootstrapping. The recognition of phylogenetic uncertainty resulted in the definition of the Bootstrap Uncertainty Range (BUR) for the age of first appearance of a given clade. The BUR is calculated as the interval of geological time in which the diversification of a given clade can be inferred to have occurred, based on the temporal information of the fossil record and the topologies of the bootstrap trees. Divergence times based on BUR analyses were calculated for three clades of turtles: Testudines, Pleurodira and Cryptodira. This resulted in extensive uncertainty ranges of topology-dependent minimal divergence dates for these clades.
近年来，提高进化枝分歧时间分子定年性能的方法有了显著改进。利用化石记录中进化枝的首次出现对分子定年进行校准，是推断各类群最小多样化时间的关键步骤，而灭绝类群的选择会强烈影响分子定年结果。在此，我们通过非参数自展法评估灭绝类群系统发育位置的不确定性。系统发育不确定性的识别导致了给定进化枝首次出现年龄的自展不确定性范围（BUR）的定义。BUR计算为地质时间间隔，在该间隔内，基于化石记录的时间信息和自展树的拓扑结构，可以推断给定进化枝的多样化已经发生。基于BUR分析计算了龟类的三个进化枝：龟鳖目、侧颈龟亚目和曲颈龟亚目分歧时间。这导致这些进化枝的拓扑依赖最小分歧日期存在广泛的不确定性范围。
