'Mother' of All Mammals is Common Ancestor of Humans
Humans may have a new ancestor: a small, insect-eating, four-legged mammal that lived millions of years ago. An international six-year-study has reconstructed the extended family tree of mammals, and has found our common ancestor.
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The study, published in the journal Science, focused on "placental mammals", a branch of species that includes humans, horses, whales and others. The researchers used a massive trove of data that included genetic and physical traits from both modern and prehistoric species so that they could reconstruct the family tree of mammals. In order to record the data, the researchers used a system called MorphoBank. Its data set, which included more than 4,500 traits detailing characteristics such as hair type and teeth structure, is 10 times larger than what was previously used to study mammal relationships.
From this information, the researchers were able to get a picture of the "mother" of all mammals. It had a diet of insects, a fleshy nose, a light underbelly and a long tail. Essentially, our ancestor looked like a small-than-rat-sized cross between a squirrel and a possum. The only reason that scientists were able to get this detailed description, though, was due to the unprecedented combining of both DNA and anatomical data for placental mammals.
The researchers didn't just find our common ancestor, though. They were also able to conclude that placental mammals rose between 200,000 to 400,000 years after the extinction of non-avian dinosaurs about 85 million years ago. That's an unprecedented 36 million years later than previous models had predicted.
The mammal family tree also shows that the fragmentation of Godwana, which was one of two supercontinents that once created the single Pangaea, occurred well before the origin of placental mammals. This negates a previous theory which said that mammal diversification was connected to the breakup of the supercontinent.
These findings could help shed light on the study of evolutionary history and could give scientists a better understanding of species diversification.
You can check out a picture of this furry mammal here.