17 Million Year Old Fossil Gives Clues On Human Evolution

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The whale, known as Ziphiidae, lived at a time when the East African plateau was covered by dense forests, and was significantly lower than it is right now. The timing of the uplift has long puzzled scientists, because research into a rediscovered fossil suggests that it stopped moisture from the Indian Ocean from reaching the vegetation, and the area became a savannah, writes Laura Geggel for Discovery.

History of human ancestors

One theory is that our now extinct ancestors may have lived in trees in East Africa, but then gradually started walking on two feet after the area turned into grassland. The whale fossil helps researchers get a closer estimate of the timing of the uplift, which a new study claims occurred between 17 and 13.5 million years ago.

The whale fossil was originally found in 1964, but a study was not published until 1975. Incredibly the skull was then misplaced until 2011. The beaked whale usually lives in the ocean, but it was found 460 miles from today’s coastline, at an elevation of 2,100 feet.

At first the scientists were confused by its location, but later theorized that the 23-foot-long whale could have moved into a river system by mistake from its home in the Indian Ocean. Later findings showed that the whale had indeed died in a river-lake environment.

Fossil helps date uplift of East African plateau

Researchers studied other instances of whales getting lost in river systems in order to model how high the East African plateau would have been at the time, before comparing it with its height today. They find that the northern part of the East African plateau must have been lifted approximately 1,925 feed over the course of the pats 17 million years.

Evidence has been discovered that the uplift had already begun around 13.5 million years ago, caused by hot material rising through the Earth’s mantle and exerting pressure on its crust, known as mantle plumes. However without the fossil it would have been hard to date to the uplift.

The curious case of the rediscovered whale skull should remind paleontologists to study the location and age of any fossil that they discover, lest they find it informative in ways that they had not thought of before. Who knew that a whale fossil could in fact inform us on the earliest history of humanity.

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