A study explores diversity patterns in the early hominin fossil record. Researchers have suggested that climate change is the primary driver of fluctuations in diversity in the hominin fossil record. However, the influence of uneven sampling on diversity patterns remains unclear. Simon J. Maxwell and colleagues applied sampling-corrected methods to the hominin fossil record to examine fluctuations in species diversity from 7 million years ago to 1 million years ago. The authors compared taxic diversity, which is a measure of the number of fossil occurrences, and phylogenetic diversity, which is a measure of the number of occurrences and inferred gaps in sampling, with sampling metrics related to collection effort and the amount of exposed rock available to sample. The results revealed correlations between taxic diversity, rock exposure, and collection effort, indicating that nonuniform fossil sampling rather than climate dynamics might explain the pattern of early hominin taxic diversity in the fossil record. Moreover, the authors suggest that peak taxic diversity at 1.9 million years ago reflects maximal rock exposure and collection effort, rather than a major evolutionary transition. In contrast, phylogenetic diversity estimates peak at 2.4 million years ago and were unrelated to sampling metrics. According to the authors, the findings demonstrate that additional research is required to reliably determine the role of climate in hominin evolution.
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Article #17-21538: "Sporadic sampling, not climatic forcing, drives observed early hominin diversity," by Simon J. Maxwell, Philip Hopley, Paul Upchurch, and Christophe Soligo.
MEDIA CONTACT: Simon J. Maxwell, Birkbeck, University of London, UNITED KINGDOM; e-mail: <simon.maxwell.14@ucl.ac.uk>
Journal
Proceedings of the National Academy of Sciences