Get ready for some 12-million-year-old "panda-monium!"
Spanish researchers have discovered fossils they say could be from the oldest identified relative of the giant panda. The specimens are from a species the scientists are calling Kretzoiarctos beatrix, and they are in the range of 11.5 million to 12.5 million years old, according to lead study author Juan Abella, at the National Museum of Natural Sciences in Spain.
These fossils, described in the journal PLOS ONE, were found in northeast Spain, and come from two adult individuals. One set, which Abella and colleagues described last year in the journal Estudios Geológico, consists of two teeth. The other includes a broken mandible and incomplete upper carnassial (large tooth).
This new study takes into account the both sets of fossils, and compares them with more species, Abella said. The additional fossils allowed the scientists to come up with the genus Kretzoiarctos beatrix.
The oldest fossils in the panda lineage that have been found in China are significantly younger - they are thought to be between 7.2 and 8.2 million years old, said Abella.
However, the scientists are not claiming to know that pandas evolved in Spain and then migrated to China. There is not enough information to make this statement.
So, don't go around calling this the missing panda link, Abella said. It's certainly possible that there are other older panda relative fossils out there waiting to be found. Moreover, we don't know for sure what the panda family tree looked like.
"That fossil record is very fragmentary and so it is difficult to state 100% sure that one fossil species was the direct ancestor of an extant one," Abella said in an e-mail.
When this proto-panda roamed Spain, the climate was more humid and warm, Abella said. That means there fruits and plants were in greater abundance, which may have enabled the ancient panda to incorporate more plants in its diet.
Scientists aren't sure whether bamboo was present in their habitat at that time, but there may have been similar plants associated with humid climates, Abella said.
There are obviously still a lot of unknowns about the prehistoric pandas these fossils potentially came from. More specimens from the same place would be needed to determine the sex of the creatures and exactly how big they were, Abella said.
"The discovery is very important to understand the origin of the lineage that leads to the giant panda millions of years after," Abella said. "It may also help scientists to understand the adaptations in both the skull and jaw, that helps, this unique bear, to be able to feed on hard bamboo stems."
Bears have been living in the Iberian Peninsula for at least the last 11.5 million years, Abella said. There are still brown bears living in the mountains in the north of Spain.