The giant panda (Ailuropoda melanoleuca) is only found in forested mountain ranges in central China. It famously eats little but indigestible bamboo, despite having the digestive system of a carnivore, and is one of the world’s most iconic vulnerable species. This black-and-white bear is the only surviving member of the Ailuropodinae subfamily, part of the larger Ursidae family.
Nobody really knows how the giant panda evolved. Few fossils of its relatives have been found, so its lineage is almost as hotly debated as that of humans.
Now palaeoanthropologist David Begun at the University of Toronto in Canada has found a set of fossil teeth in the town of Rudabánya, Hungary.
Begun was looking for ancient hominid bones when he spotted the teeth trapped beneath a rhino’s shoulder blade. The teeth are 10 million years old, placing them in the late Miocene.
The team compared the shape, structure and wear patterns of the teeth with those of other bears. Such wear patterns, created when food being chewed scrapes away some tooth enamel, can reveal what an animal ate – and in this case they were similar to those of giant pandas. “Both species consumed tough plant foods, requiring shearing rather than crushing of food during chewing,” says de Bonis. “This tell us that the way of life of the panda’s ancestors was very similar to the modern panda.”
The teeth belonged to a previously unknown panda, and the team has named the species Miomaci panonnicum. “Miomaci could be considered not like a direct ancestor, but more like a ‘cousin’ of the modern panda,” says de Bonis. “Their lineage probably separated in the middle Miocene period.”
“From the description, it appears to be closer to the split between giant pandas and the rest of the carnivores, including bears,” says Russell Ciochon at the University of Iowa. “The fossil they found lacks the very specialised dental anatomy found in modern giant pandas, which evolved in southern China around 2 million years ago, and is believed to be when pandas became dependent on bamboo.”
Since giant pandas are confined to China, we had assumed that the panda family has been living there since shortly after it split off from other bears. Some fossils support that idea. Fossil pandas can be found in China as far back as 8 million years ago.
However, in 2012 scientists found teeth from possibly the oldest known direct ancestor of the giant panda, Kretzoiarctos beatrix. They were 11.6 million years old and were discovered in Spain, suggesting the giant panda’s ancestors originated in Europe before migrating to Asia.
Climate may have played a role. When Miomaci lived, Europe was warmer and wetter than it is today. The chemical make-up of other teeth from Rudabánya suggest the area was once a lush subtropical forest on the shores of a lake. Such forests disappeared from Europe about 5 million years ago, and this may have spelt the demise of European pandas. “The environment cooled and dried out,” says de Bonis. “There was a change in the faunas in Europe, and the species linked to dense warm forest disappeared.” China could have been the only congenial home for surviving pandas.
Source: new scientist