Danuvius guggenmosi is an extinct great ape discovered in Germany that offers a new perspective on the evolution of upright posture. This primate possessed a unique anatomical combination of features seen in modern apes and the human lineage. The preservation of its limb bones suggests a method of movement that redefines the timeline and location for the origins of bipedalism. The discovery provides a potential physical model for the last common ancestor shared by humans and other great apes.
Context of the Discovery
The fossilized remains of Danuvius guggenmosi were unearthed in the Hammerschmiede clay pit, situated in the Allgäu region of Bavaria, southern Germany. Excavation work at the site between 2015 and 2018 yielded the primate fossils, which belonged to at least four individuals. The most complete specimen was a partial skeleton of a male, which offered unprecedented detail for reconstructing its locomotion.
The research team, led by paleoanthropologist Professor Madelaine Böhme from the University of Tübingen, published their findings in 2019, formally describing the new species. The specific name guggenmosi honors Sigulf Guggenmos, the amateur archaeologist who initially discovered the rich fossil site. Finding such a well-preserved partial skeleton with complete long bones is rare for this time period.
The Miocene Epoch and Classification
Danuvius guggenmosi dates back to approximately 11.62 million years ago, placing it firmly within the Late Miocene epoch. This period is key because it brackets the time when the evolutionary paths leading to modern humans and great apes are thought to have diverged. The environment Danuvius inhabited in Bavaria was likely a humid, forested ecosystem with meandering streams.
Scientifically, Danuvius is classified as a Hominoid, the broad group encompassing all great apes, gibbons, and humans. More specifically, its dental anatomy links it to the dryopithecines, a group of extinct European great apes. Danuvius was a relatively small primate, with males estimated to weigh around 31 kilograms and females closer to 18 kilograms.
The distinction between Hominoid (all apes) and Hominin (the group including modern humans and their extinct ancestors) is central to understanding the fossil. Although Danuvius is an ape, its anatomy suggests it may closely resemble the common ancestor from which both modern great apes and the Hominin lineage descended. Its age pushes the physical characteristics of this common ancestor millions of years further into the past than previously evidenced by African fossils.
Skeletal Evidence for Unique Locomotion
Analysis of the fossil’s postcranial skeleton revealed a unique combination of traits suggesting a new form of movement termed “extended-limb clambering.” This locomotor repertoire required equal contributions from the forelimbs and the hindlimbs, unlike the forelimb-dominated movement of modern apes or the hindlimb-dominated movement of humans. The ape’s body structure allowed it to maintain a straight, upright posture while navigating branches in the trees.
The lower body exhibited several features typically associated with bipedalism, notably an elongated lumbar region of the spine and a broad, flat ribcage. This anatomy helped center the body mass over the hips and legs, a prerequisite for balancing on two feet. Furthermore, the knee and ankle joints were robust and adapted for weight-bearing, regularly subjected to the compressive forces of an upright stance.
The ape’s femur and tibia suggest it was capable of fully extending its hip and knee joints, a posture similar to humans and unlike the habitually bent-kneed posture of living African great apes. However, the feet retained a powerful, grasping capability, featuring a large, opposable big toe. This toe would have allowed Danuvius to securely grip branches while standing and walking upright in the canopy.
In contrast, the upper body displayed classic ape-like features, including long forearms and highly flexible elbows and wrists. These features were beneficial for suspension, allowing the ape to hang beneath branches, a behavior known as suspensory locomotion. The robust finger bones also indicate a strong grip for holding onto supports. This mosaic anatomy suggests that Danuvius spent its life walking bipedally along tree branches and using its arms for support, suspension, and balance.
Implications for Hominin Evolution
The discovery of Danuvius guggenmosi offers a profound challenge to long-held theories regarding the origin of human bipedalism. For decades, the prevailing hypothesis suggested that upright walking evolved on the ground in the African savannah, after the ancestors of humans descended from the forests. Danuvius, however, provides direct evidence that the fundamental skeletal adaptations for upright posture were present in an arboreal ape living in Europe millions of years earlier.
The fossil suggests that the capacity for an extended-limb, upright stance evolved in the trees, a process known as orthograde arboreality. This predates the earliest widely accepted hominin fossils, such as Ardipithecus and Australopithecus, by several million years. The evidence shifts the evolutionary narrative, suggesting that the initial innovation of upright posture was not a unique development of the human lineage but a shared, ancient characteristic of the Hominoid family.
Rather than being a sudden, single event, the ability to walk upright may have been an ancient trait inherited from an ape like Danuvius. This initial arboreal bipedalism could have later been co-opted and refined for efficient ground travel by early hominins migrating to the open savannah.