A species of giant panda lived in eastern Europe 6 million years ago, according to scientists who studied the animal’s fossilized teeth.
The discovery came from forgotten fossilized teeth, originally discovered in the late 1970s in Bulgaria’s Sredna Gora mountain range. The teeth—an upper carnassial tooth and an upper canine—had been collecting dust on a shelf in the Bulgarian National Museum of Natural History until now.
A team of researchers recently studied the teeth and determined they belong to the genus Agriarctos, which distinguishes the long-gone bears from the extant giant panda, a member of the group Ailuropoda. The team’s findings about the ancient teeth were published this week in the Journal of Vertebrate Paleontology.
The extinct panda is now named Agriarctos nikolovi, after the paleontologist who added the bear remains to the museum’s collection. The bear lived during the Miocene epoch, which ended about 5.3 million years ago, and, based on the size of its teeth, it was probably about the size of a modern giant panda.
Nikolai Spassov, a paleontologist at the Bulgarian National Museum of Natural History, said in a Taylor & Francis release that A. nikolovi is a close relative of modern pandas, not a direct ancestor.
“[The teeth] had only one label written vaguely by hand,” Spassov said in the release. “It took me many years to figure out what the locality was and what its age was. Then it also took me a long time to realize that this was an unknown fossil giant panda.”
The bear’s teeth—blackened by the coal-rich deposits in which they were found—were studied alongside teeth from nine other bear species that range from southeastern China to eastern France. Besides the fact that there is scant evidence for bamboo (the staple food of modern panda bears) in ancient Bulgaria, analysis of A. nikolovi’s teeth indicated the animal would’ve had a tough time breaking down bamboo’s woody stems.
The tooth analysis revealed that A. nikolovi’s teeth were similar in shape and size to those of extant pandas, with a large canine tooth and cutting edges on its premolar. That led the research team to posit A. nikolovi was likely also a vegetarian bear. However, the cusps on the teeth didn’t appear strong enough to chew up bamboo’s robust, woody stems, so the team thinks the animal probably grazed on softer plant material.
As to why pandas evolved to eat mostly plants, the going theory is that there wasn’t much competition for the abundant grass. One recent study suggests that the bears may have adapted a bamboo-dominated diet more recently than previously thought.
Pandas also use their teeth to protect themselves against other bears, like in fights over mates. Similarly, A. nikolovi’s teeth probably served as a good defense against other animals in the swampy Miocene forest.
The researchers believe the ancestor of panda bears may have come from somewhere in southern Asia—somewhere between modern-day Afghanistan and Vietnam—and dispersed from there into subspecies in China and subspecies like A. nikolovi in Europe. However, the evidence for the most ancient pandas comes from Europe, so it’s possible that the first pandas emerged there and moved before the bears diversified.
It’s not certain why the Bulgarian pandas are now extinct, though the team suspects climate changes in the region—specifically, a period known as the Messianian salinity crisis, during which the Mediterranean region dried up.
“Even if A. nikolovi was not as specialized in habitats and food as the modern giant panda, fossil pandas were specialized enough and their evolution was related to humid, wooded habitats,” Sassov said in the release. “It is likely that climate change at the end of the Miocene in southern Europe, leading to aridification, had an adverse effect on the existence of the last European panda.”
If researchers can get their hands on even older panda teeth, perhaps the evolution of these unique bears can be untangled, along with why only species remains on Earth today. (Red pandas, despite their name and love of bamboo, are something else entirely.)