In 2019, paleontologists in the Ostallgäu discovered the spectacular fossil of the approximately twelve million year old ape Danuvius guggenmosi – now there is another find. At the same site near Kaufbeuren, the team has identified the relics of another prehistoric ape species. Two fossil teeth and a kneecap of the species named Buronius manfredschmidi indicate that this ape was significantly smaller than its contemporary and tended to spend more time in trees. Buronius also ate softer food than the larger Danuvius. It is the first time that two different hominid species from this period have been discovered at the same site in Europe, the researchers report.
Africa is considered the cradle of humans and their ancestors – including the great apes. For a long time, it was therefore unclear whether and when early representatives of the hominids penetrated Europe. But in recent years, paleontologists have discovered several pieces of evidence that early humans of the genus Homo were not the first immigrants to Europe: 17 million years ago, there were prehistoric apes in the area of what is now Swabia, as evidenced by the discovery of a fossil tooth in the Swabian Alpine foothills. Seven million-year-old relics have been found in Greece and Bulgaria that also come from hominids – the family group to which humans and great apes belong today. The most spectacular discovery in 2019 was probably the approximately 11.6 million-year-old ape Danuvius guggenmosi, known as “Udo”. A team led by Madelaine Böhme from the University of Tübingen had discovered numerous fossils of this ape, which was already adapted to walking upright, at the “Hammerschmiede” site near Kaufbeuren in the Ostallgäu region.
A second, smaller prehistoric ape
Now Böhme’s team is reporting on another discovery. These are two fossil teeth and a kneecap that were found a few years ago very close to the Danuvius relics. These fossils were also preserved in the fossilized sediment of the prehistoric stream that once flowed through a swampy landscape in the Hammerschmiede clay pit. However, initial investigations suggested that these three finds did not come from Danuvius, because the teeth and kneecap were significantly smaller and showed striking anatomical peculiarities. More detailed comparative analyses have now confirmed this: the three finds come from a second species of ape that was clearly different from Danuvius, as the paleontologists explain. “The morphology and size of these finds from the same Hammerschmiede layer as Danuvius require classification in a new genus,” they write. The discovery of two hominid genera in the Hammerschmiede is unique among the fossil sites of the European Miocene.
Böhme and her team chose Buronius manfredschmidi as the name for the newly discovered ape. Buronius is derived from the medieval name of the town of Kaufbeuren – Buron. The species name honors the amateur archaeologist Manfred Schmid, who made numerous fossil finds in the Hammerschmiede clay pit. Buronius’ teeth and kneecap reveal that this prehistoric ape probably weighed no more than around ten kilograms. This made it significantly smaller than all living apes, which range from around 30 kilograms for the bonobo to more than 200 kilograms for the gorilla. The newly discovered species was also smaller than Danuvius, which lives in the same area and weighs around 15 to 46 kilograms. According to the paleontologists, Buronius’ weight and size most closely corresponded to that of the siamangs, smaller relatives of the gibbons from Southeast Asia.
Different diet and lifestyle
The fossils of Buronius also provide the first clues about his way of life – and this also differed from that of his larger contemporary Danuvius. For example, Buronius – unlike Danuvius, which was adapted to walking upright – may have spent most of its time in trees. “The kneecap of Buronius is thicker and more asymmetrical than that of Danuvius,” explains Böhme. This could be explained by differences in the thigh muscles, which indicate an adaptation to climbing. Buronius’ teeth indicate another difference: “The tooth enamel thickness of Buronius is less than that of any other great ape in Europe and comparable to gorillas,” reports Böhme. “The tooth enamel of Danuvius, on the other hand, is thicker than that of all related extinct species and is almost as thick as human tooth enamel.” These features provide clues about what the primates once ate. A thin layer of tooth enamel indicates a fruit-rich, vegetarian diet, whereas a thicker layer of tooth enamel, as in humans, is typical of omnivores who also chew harder, tough foods.
Taken together, these differences could explain why the two species of great apes that lived at the same time could be found in the same area: Buronius and Danuvius apparently occupied different ecological niches. The smaller Buronius probably stayed in treetops and branches and fed mainly on fruit and leaves. Danuvius, on the other hand, was more than twice as large and able to walk upright, and probably roamed a larger area and was thus able to use more diverse food resources. This is comparable to the current syntropy of gibbons and orangutans on Borneo and Sumatra, explains the research team: While orangutans roam around in search of food, the small fruit-eating gibbons stay in treetops. The fossil finds from the Hammerschmiede now provide evidence for such a syntropy for prehistoric great apes in Europe for the first time.
Source: Madelaine Böhme (Eberhard Karls University Tübingen) et al., PLoS ONE, doi: 10.1371/journal.pone.0301002