Chororapithecus abyssinicus represents an extinct great ape whose fossil remains offer significant insights into primate evolution, helping to refine the timeline and geographic context of great ape ancestry.
Unearthing an Ancient Ape
The fossilized remains of Chororapithecus abyssinicus were uncovered in Ethiopia’s Chorora Formation. Researchers discovered nine isolated teeth from multiple individuals between 2005 and 2007. The initial scientific description of this new species was published in 2007.
Initially dated to 10-10.5 million years ago, subsequent analysis revised its age to approximately 8 million years ago. This re-dating placed Chororapithecus firmly within the Late Miocene epoch. The classification of Chororapithecus as an early member of the gorilla lineage has generated scientific discussion, with some researchers suggesting that its dental similarities to gorillas might instead be a result of convergent evolution, where similar traits evolve independently due to similar environmental pressures.
Anatomy and Lifestyle
Evidence for Chororapithecus abyssinicus comes from its nine fossilized teeth, consisting of eight molars and a single canine. These teeth are comparable in size to those of modern gorillas. Micro-computed tomography revealed distinct shearing crests on the molars, alongside relatively thick enamel.
These dental characteristics provide clues about Chororapithecus’s diet and the environment it inhabited. The presence of shearing crests suggests an adaptation for processing fibrous plant materials, such as leaves, similar to the diet of modern gorillas. Concurrently, the thick enamel indicates the ability to consume harder or more abrasive food items. This combination of features implies a varied diet rather than an exclusive reliance on fibrous vegetation. The ancient environment where Chororapithecus lived was likely a mosaic of forested lakeside habitats and savanna, supporting a diverse range of plant resources.
A Key to Primate Evolution
The discovery and re-dating of Chororapithecus abyssinicus have significantly influenced our understanding of great ape and human evolution. Its 8-million-year-old presence in Late Miocene Africa supports the idea that the gorilla lineage separated from the human-chimpanzee lineage around 10 million years ago, with the human-chimpanzee split occurring roughly 8 million years ago. This revised timeline pushes back previous estimates from molecular analyses, which often placed these divergences at later dates.
The existence of Chororapithecus in Africa strengthens the hypothesis that the earliest great apes and hominins originated on the African continent, rather than evolving in Eurasia and later migrating back to Africa. This fossil fills a significant gap in the African fossil record for great apes, a period between 12 and 7 million years ago. While its precise placement as a direct ancestor of modern gorillas remains a subject of ongoing scientific discussion, the insights gained from Chororapithecus are invaluable. It serves as an important piece of evidence that reshapes our chronological and geographical understanding of the evolutionary pathways of great apes.