Published: 16 January 2019, 19:00 | By: Ute Schönfelder
An international research team has used robotics and biomechanics to recreate the movements of an early terrestrial vertebrate. The team, with members from Humboldt University in Berlin (HU), Friedrich Schiller University in Jena and the École Polytechnique Fédérale de Lausanne (EPFL), studied the fossil finds of Orobates pabsti a four-legged creature approximately one metre long. They not only obtained morphological descriptions of the animal, but also subjected them to functional analyses using computer simulation. As the grand finale to the multi-year study, the team led by Prof. John Nyakatura designed and built a biomimetic robot the OroBOT which now offers new insights into the biology of the ancient fossil. The study can be found in the current issue of the renowned journal Nature and it is actually the cover story.
In this paper, the scientists demonstrate convincingly the knowledge that can be gained using the innovative methodology of robotics-inspired biology. With the OroBOT, built by the EPFLs Biorobotics laboratory, it was possible to test various locomotion patterns of the primeval creature. "The robot is able to move in the same pattern as that suggested by the simulation and thus can exactly reproduce the trackway of fossilised Orobates footprints preserved in the rock," explains John Nyakatura. "This provides us with a novel research tool that helps us to systematically run through a series of variables for locomotion and evaluate their plausibility."
The zoologist and lead author of the study, John Nyakatura, currently works in the Cluster of Excellence Image Knowledge Gestaltung. An interdisciplinary laboratory at Humboldt University. However, the origins of his work and that of the whole team lie in the Free State of Thuringia and Jena. Not only do the fossilised tracks of the primaeval creature come from what is now the Thuringian Forest. It is in this area, in a field near the small town of Tambach-Dietharz, that a well-preserved skeleton of Orobates pabsti was found in 1998. The skeleton is nearly 300 million years old and is now kept in the museum in Friedenstein Castle in the town of Gotha. In addition, it was at the Institute of Zoology and Evolutionary Research at Friedrich Schiller University in Jena that the initial investigations of the long-extinct animals movements were carried out.
This was made possible above all by the high-speed X-ray video facility at the institute, which is led by Prof. Martin S. Fischer. As part of a multi-year project funded by the Volkswagen Foundation, Fischer and his then postdoc Nyakatura studied the locomotion systems of animals similar to Orobates, such as skinks, Mexican salamanders and caimans. "With the help of high-speed X-ray videos and force measurements, we were able to study the biomechanics of the sprawling gait. We were able to use the mechanical characteristics shared by all the – still extant animals involved in the study as a basis for reconstructing the locomotion of the Orobates fossil," says Nyakatura. In cooperation with the Hamburg-based scientific illustrators Jonas Lauströer and Amir Andikfar, with whom Prof. Fischer has worked closely for a decade, an animated Orobates skeleton was then created, which could walk in the fossilised footprints. Funded by a grant from the Daimler and Benz Foundation, Nyakatura, now working from Berlin, incorporated these findings into the OroBOT, in cooperation with his colleagues in Lausanne.
Nyakaturas PhD supervisor and co-author of the Nature publication, Martin Fischer, is certain that the success of the interdisciplinary research partnership will be a catalyst for further projects. "With this work, we have laid the methodological foundations that will enable the systematic reconstruction of other fossils," says Fischer. In future, it would no longer only be the technical applicability of findings from biological research that would be in demand. "On the contrary, we will increasingly ask how technical systems can be used to gain biological knowledge."
Orobates pabsti is regarded as a key fossil for understanding the evolution of terrestrial vertebrates, as it is a representative of the evolutionary line that has led to todays mammals, turtles, lizards, crocodiles, and birds. These successful groups of animals and also all extinct dinosaurs go back to a hypothetical close relative of Orobates. By reconstructing the way in which the creature moved, the researchers were able to show that Orobates could already walk effectively on land and, unlike amphibious animals such as salamanders, was probably already independent of water several million years earlier than previously assumed.
Photos, Videos and answers to frequently asked questions can be found here.
Nyakatura, JA et al. 2019. Reverse-engineering the locomotion of a stem amniote. Nature 565, 351355, http://dx.doi.org/10.1038/s41586-018-0851-2