New geological and palaeontological age constraint for the gorilla-human lineage split
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Summary
This summary is machine-generated.New dating of Ethiopian fossils reveals African ape and human origins between 9 and 7 million years ago. The findings support in situ evolution of the human-gorilla clade in Africa.
Area Of Science
- Palaeobiology
- Geochronology
- Primate Evolution
Background
- The period between 12 and 7 million years ago is critical for understanding African ape and human origins.
- Fossil evidence from sub-Saharan Africa for this period is scarce.
- The Chorora Formation in Ethiopia was previously dated to ~10.5 million years ago, yielding fossils like Chororapithecus abyssinicus.
Purpose Of The Study
- To accurately date the Chorora Formation sediments and associated fossils.
- To revise the timeline for the human-gorilla split.
- To investigate mammalian evolution and faunal interchange in Africa during the late Miocene.
Main Methods
- New field observations.
- Geochemical analysis.
- Magnetostratigraphy.
- Radioisotopic dating.
Main Results
- The Chorora Formation sediments are dated between ~9 and ~7 million years ago.
- Chororapithecus abyssinicus fossils are dated to ~8.0 million years ago.
- The assemblage includes the first sub-Saharan mammalian fossils spanning ~8.5 to 7 million years ago.
- Evidence suggests indigenous African evolution of mammalian lineages and a potential ancestral-descendent link between Nakalipithecus nakayamai and C. abyssinicus.
- Faunal provinciality between East Africa and Eurasia intensified around ~9 million years ago.
Conclusions
- The Chorora Formation provides crucial evidence for African ape and human origins.
- The findings support the hypothesis of in situ evolution of the Gorilla-Pan-human clade within Africa.
- The revised chronology aligns with deeper divergence estimates for humans and great apes.