Widespread loss of mammalian lineage and dietary diversity in the
early Oligocene of Afro-Arabia.
Abstract
Diverse lines of geological and geochemical evidence indicate that the Eocene-Oligocene transition (EOT) marked the onset of a global cooling
phase, rapid growth of the Antarctic ice sheet, and a worldwide drop
in sea level. Paleontologists have established that shifts in
mammalian community structure in Europe and Asia were broadly
coincident with these events, but the potential impact of early
Oligocene climate change on the mammalian communities of Afro-Arabia
has long been unclear. Here we employ dated phylogenies of multiple
endemic Afro-Arabian mammal clades (anomaluroid and hystricognath
rodents, anthropoid and strepsirrhine primates, and carnivorous
hyaenodonts) to investigate lineage diversification and loss since the
early Eocene. These analyses provide evidence for widespread mammalian extinction in the early Oligocene of Afro-Arabia, with almost
two-thirds of peak late Eocene diversity lost in these clades by ~30
Ma. Using homology-free dental topographic metrics, we further
demonstrate that the loss of Afro-Arabian rodent and primate lineages
was associated with a major reduction in molar occlusal topographic
disparity, suggesting a correlated loss of dietary diversity. These
results raise new questions about the relative importance of global
versus local influences in shaping the evolutionary trajectories of Afro-Arabia’s endemic mammals during the Oligocene.
Open access:
https://www.nature.com/articles/s42003-021-02707-9
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