Comparison of the micromorphology of a chewing surface of the modern giant panda (left) with Kretzoiarctos (center) and the modern brown bear (right): the pattern of grooves and cavities is caused by wear to the teeth. It is characteristic of the different mechanical properties of the food. Credit: Alexander Daasch, Leibniz Institute for the Analysis of Biodiversity Change, Museum of Nature Hamburg, and Nikolaos Kargopoulos
Phys.org has a nice summary of a new paper in the journal Papers in Palaeontology and Geobios, which sheds light on the ancestry of the giant panda. The fossils were found at the Hammerschmiede clay pit, a fossil site in southern Germany that dates to about 11.5 million years ago. Fossil teeth of Kretzoiarctos beatrix, which is thiught to be the oldest ancestor of the modern giant panda, are found a this locatity. Researchers looked at the macro- and micromorphology of these teeth and found clues to the dietary habits of these animals.
At the macro level, the form of the teeth changes depending on their role in processing food, which gives an indication of an animal's general primary sources of food. At the micro level of the dental surface, scratches and pits can be found that are caused by food particle contact with the tooth.
"The characteristics of these surface changes can give clues to the dietary habits of an animal in a short period before its death," says the scientist.
The research team compared the macro- and micromorphology of the Kretzoiarctos teeth with those of brown bears, polar bears, South American spectacled bears and both the giant pandas of today and extinct giant pandas. They concluded that the bear from Hammerschmiede did not specialize in hard plants like the modern panda, but nor was it a pure carnivore like the polar bear.
The diet of the extinct species was more like that of a modern brown bear and contained both plant and animal elements. "These results are important to our understanding of the evolution of bears and the development of herbivory in giant pandas. It turns out that Kretzoiarctos beatrix, the oldest of the pandas was a generalist. Specialization in the panda's diet only came about late in its evolution," says Böhme.
