Discover the European ancestor of the giant panda (or not?)

Photo: Velizar Semyonovsky

It all started with a wonderful discovery in the National Museum of Natural Sciences in the Bulgarian capital Sofia. This is, for the sake of good understanding, not an obscure exhibition space in a back street, but a research institution that is over a century old and considered the oldest in the Balkans and possesses the richest collection in the field in the region. Nikolai Spasov, a vertebrate zoologist, hiding deep in a vault, found fossilized teeth that had been gathering dust there since the late 1970s. Equally ancient archival records taught him that the upper fourth premolar and upper canine tooth were originally cataloged by paleontologist Ivan Nikolov.

“There was nothing more than a faint handwritten poster,” says Professor Spasov. It took me years to figure out the age of the teeth and exactly where they were found. After that, it took a long time before I understood that these were the fossil remains of a hitherto unknown giant panda. A new species was then named after the paleontologist who discovered the teeth: Agriarctos Nikolovich.

Why is Spasov a. Nikolovich as a new species? In short, the animal must have lived in a forested wetland six million years ago, on a largely vegetarian diet. The a. Nikolovich More specifically, they should be fed soft plant matter. So not or certainly not always and only with bamboo. The tips of the fossil teeth do not seem strong enough to crush the hard, woody stems of that plant. Which almost automatically leads us to the most evocative question: What is the evolutionary relationship with the Chinese panda? The point of similarity is the size of the teeth, hence the suspicion of a similar or perhaps slightly smaller body size. But it would be simplistic to deduce from this direct connection to the ancestors. It is a matter of (distant) kinship.

Study co-author Qigao Jiangzuo, a researcher specializing in Peking University, investigated the evolutionary family tree a. Nikolovy. He sums it up like this: “It belongs to Europodina, a subfamily of bears, of which only one survivor remains: the giant panda, which today lives only in central China. However, I used to find the family all over Europe and Asia. In our study, we present two possible pathways about the spread of Eluropodina. One possible evolutionary path is that it came from Asia and culminated in Europe in a. Nikolovy.

His colleague Spasov seems to be more convinced of the second hypothesis: “The fossil data indicate that the oldest members of the bear family were found in Europe. This may indicate that it developed in Europe, and then spread to Asia, where the ancestors of another genus, and Eylore Arctus (“Cat Bear”). These early pandas could then have evolved into the later “modern” giant pandas.

In short, Spasov concludes: “This research also proves how little we knew about prehistoric nature and how historical discoveries in paleontology continue to raise new questions.”