对古人类分类群起源和灭绝的可靠估计是解决许多古人类学问题的核心,包括那些与宏观进化模式有关的。人类时间范围的时间安排可用于测试系统发育假设产生的时间顺序预测。例如,亲缘关系的假设,基于形态学数据,预测两个分类单元之间没有时间范围重叠。然而,由于化石记录本身及其采样的不完整性,几乎肯定低估了化石分类群的观测时间范围,这降低了观察时间重叠的可能性。这里,我们专注于一个众所周知且被广泛接受的早期人类谱系,南方古猿,并在其起源和灭绝日期上放置95%的置信区间(CI)。我们这样做是为了评估它的时间范围是否与它是ramidusArdipithecusramidus的亲生后代和/或最早声称的Homo代表的直接祖先(即,Ledi-Geraru)。我们发现Ar的最后出现。ramidus属于Au的起源CI。anamensis-afarensis,而声称人类的首次出现是在灭绝CI之后。这些结果与从Au进化而来的人类是一致的。anamensis-afarensis,但是Ar之间的时间重叠。Ramidus和Au.此时不能拒绝anamensis-afarensis。虽然需要额外的样本,未来的研究应该扩展我们的初步分析,以纳入围绕Ar的范围端点的不确定性。ramidus和最早的Homo.总的来说,我们的研究结果表明,为了更好地了解进化枝历史中进化事件发生的时间,需要量化人类分类群出现和消失的不确定性。
Reliable estimates of when hominin taxa originated and went extinct are central to addressing many paleoanthropological questions, including those relating to macroevolutionary patterns. The timing of hominin temporal ranges can be used to test chronological predictions generated from phylogenetic hypotheses. For example, hypotheses of phyletic ancestor-descendant relationships, based on morphological data, predict no temporal range overlap between the two taxa. However, a fossil taxon\'s observed temporal range is almost certainly underestimated due to the incompleteness of both the fossil record itself and its sampling, and this decreases the likelihood of observing temporal overlap. Here, we focus on a well-known and widely accepted early hominin lineage, Australopithecus anamensis-afarensis, and place 95% confidence intervals (CIs) on its origination and extinction dates. We do so to assess whether its temporal range is consistent with it being a phyletic descendant of Ardipithecus ramidus and/or a direct ancestor to the earliest claimed representative of Homo (i.e., Ledi-Geraru). We find that the last appearance of Ar. ramidus falls within the origination CI of Au. anamensis-afarensis, whereas the claimed first appearance of Homo postdates the extinction CI. These results are consistent with Homo evolving from Au. anamensis-afarensis, but temporal overlap between Ar. ramidus and Au. anamensis-afarensis cannot be rejected at this time. Though additional samples are needed, future research should extend our initial analyses to incorporate the uncertainties surrounding the range endpoints of Ar. ramidus and earliest Homo. Overall, our findings demonstrate the need for quantifying the uncertainty surrounding the appearances and disappearances of hominin taxa in order to better understand the timing of evolutionary events in our clade\'s history.