The giant pandas are among the best known and at the same time most endangered species on our planet. Just under 3,000 animals live in the bamboo forests of China. Unlike other bears, they are highly specialized herbivores: they only eat bamboo. In 2012, the fossil of Kretzoiarctos, the oldest known ancestor of modern-day pandas, was discovered in Spain. Whether the pandas developed in Asia or in Europe has been a matter of debate ever since.

Now paleontologists have identified another European panda. The giant panda, christened Agriarctos nikolovi, lived around six million years ago in the humid swamp forests of present-day Bulgaria and is the last and most developed primeval panda in Europe to date. “It was not a direct ancestor of today’s giant pandas, but it was a close relative,” explains Nikolai Spassov from the Bulgarian National Museum of Natural History in Sofia.

Spassov discovered the existence of Agriarctos nikolovi when he examined two fossil teeth that had been kept in the museum for a good 40 years. “They only had a sparsely handwritten label,” says Spassov. “It took me years to find out where they came from and how old they were.” It also took some time to assign them to the fossil giant pandas.

Analysis of the teeth indicates that the European giant panda was likely similar in size and stature to modern-day giant pandas of the genus Ailuropodina. Unlike them, however, Agriarctos probably did not eat bamboo: On the one hand, this was hardly ever found in Europe even then, and on the other hand, the teeth were not strong enough to be able to crack the hard stalks of the bamboo, as the researchers explain.

The European giant panda was therefore already a vegetarian, but probably ate softer plant material. This is also supported by the place where it was found: the teeth come from a lignite layer that was formed from deposits in a damp swamp forest. In this habitat, the panda probably mainly ate the leaves of the trees growing there.

“Although Agriarctos nikolovi was not as highly specialized in habitat and diet as the modern giant panda, the evolution of fossil pandas is likely closely linked to humid, forested habitats,” explains Spassov. “Presumably, competition from other bears and predators drove giant pandas to specialize in plant-based foods in such swampy habitats.”

However, this specialization could have been the undoing of the European giant panda. Because around six million years ago, the Messinian salinity crisis drastically changed the climate in the Mediterranean region and the Balkans: the Mediterranean Sea was cut off from the Atlantic Ocean by an uplift of the seabed near Gibraltar and gradually dried up. The climate in the surrounding regions became drier.

This also dried up the swamp forests where Agriarctos nikolovi lived at that time. “It is very likely that the climate change in southern Europe at the end of the Miocene also had negative consequences for the existence of European pandas,” says Spassov. “Probably the Messinian salinity crisis contributed to the disappearance of this last European panda.”

However, it remains a mystery where and how the giant pandas evolved. “The common ancestor of Agriarctos and Ailuropodina is still unknown,” the paleontologists explain. The region of origin of the pandas remains unclear. On the one hand, there is some evidence that it originated in South Asia, but there are no corresponding fossils so far,

“On the other hand, the oldest representatives of this group of animals were found in Europe. And considering the wide distribution of mid-Miocene wet forests in Europe, the hypothesis of a European origin cannot be ruled out,” Spassov and colleagues write. More fossil finds are needed to answer this question.

What: Taylor

Author: Nadja Podbregar

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The original to this article “Giant pandas in Europe: Palaeontologists identify teeth six million years old” comes from scinexx.