Savanna tree evolutionary ages inform the reconstruction of the paleoenvironment of our hominin ancestors.
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1.54 MB
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Resource type
Journal article
Date published
July 24, 2020
Abstract
Ideas on hominin evolution have long invoked the emergence from forests into open habitats as generating selection for traits such as bipedalism and dietary shifts. Though controversial, the savanna hypothesis continues to motivate research into the palaeo-environments of Africa. Reconstruction of these ancient environments has depended heavily on carbon isotopic analysis of fossil bones and palaeosols. The sparsity of the fossil record, however, imposes a limit to the strength of inference that can be drawn from such data. Time-calibrated phylogenies offer an additional tool for dating the spread of savanna habitat. Here, using the evolutionary ages of African savanna trees, we suggest an initial tropical or subtropical expansion of savanna between 10 and 15 Ma, which then extended to higher latitudes, reaching southern Africa ca. 3 Ma. Our phylogenetic estimates of the origin and latitudinal spread of savannas broadly correspond with isotopic age estimates and encompass the entire hominin fossil record. Our results are consistent with the savanna hypothesis of early hominin evolution and reignite the debate on the drivers of savanna expansion. Our analysis demonstrates the utility of phylogenetic proxies for dating major ecological transitions in geological time, especially in regions where fossils are rare or absent or occur in discontinuous sediments.
Funder
| Funder name | Awards |
Genome Canada / Ontario Genomics Institute | 2008-OGI-ICI-03 |
University of Johannesburg (Analytical Facility), South Africa | |
Journal title
Scientific Reports
Volume
10
Issue
1
Article number
12430
Publisher
Springer Science and Business Media LLC
Place of publication
Berlin/Heidelberg, Germany
eISSN
2045-2322
Date accepted
March 31, 2020
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Rights statement
In Copyright