In the dark seas of the ancient world, few creatures were as interesting as the plesiosaur: a long-necked marine reptile with four large flippers. These fearsome predators dominated the oceans in the Mesozoic Era, but their unusual body plan made them a puzzle for researchers.
For decades, scientists have debated how these creatures possibly used their four flippers to navigate the water, but now a team of researchers may have cracked the code.
Scientists Restore History of How Plesiosaurs Moved
A joint team from Tohoku University, Kanagawa University, and the University of Manchester started an experiment to reimplement the swimming motion of the plesiosaur.
To do this, they created a bio-inspired control system that was integrated into a robot designed to mimic the ancient swimmer's movements. This is the robotic mechanism wherein the flipper movements can be adjusted directly in real-time so it could mimic the flexible and adaptive swimming techniques that the plesiosaur must have employed.
Bio-Inspired Control System: Modeling Prehistoric Adaptations
According to Interesting Engineering, plesiosaurs had a brilliant history from the Late Triassic through to the Late Cretaceous, living side-by-side with dinosaurs but uniquely ruling the seas.
Streamlined bodies and powerful flippers were given to it, well suitable for aquatic life with less resistance and with efficient propulsion.
The researchers created a plesiosaur-inspired control system design for a robot that could function as a plesiosaur might have done. Because of this, the four flippers of the robot had the ability to synchronize and move in coordination, relying on speed, direction, and water conditions.
With this model, the team was finally able to discover that it is likely that plesiosaurs changed their motion based on swimming needs such as varied speeds or a change in environmental conditions.
Flexible Decentralized Control: A Novel Perspective on Prehistoric Mobility
The researchers, led by assistant professor Akira Fukuhara at Tohoku University's Research Institute of Electrical Communication, explored an innovative, decentralized control system inspired by the adaptable limb movement of four-legged animals.
In this case, independent flipper motion coordinated with each other created a smooth and responsive type of movement.
According to lead researcher Akio Ishiguro, flexibility would have meant that these plesiosaurs could actually navigate their world with some variation of speed and agility responsive to the changing conditions of the water.
"Instead of focusing solely on how water interacts with plesiosaur bodies – that is, the hydrodynamics of swimming – we decided to examine how these animals controlled their movement," Ishiguro said.
This decentralized control system, according to Ishiguro, brings us closer to understanding how these marine reptiles swam. Building a robot that moves like a plesiosaur will allow scientists to better visualize and analyze the behaviors of these ancient creatures.
Extinct Animal Locomotion
The study, published in Nature.com finally throws light on the elusive movement patterns of extinct animals, a very complex topic because fossils hardly ever preserve soft tissues that reveal motion.
Plesiosaurs and other extinct species are relatively anatomically very different from modern animals hence difficult to decipher as far as their locomotion is concerned.
More anatomical detail about the plesiosaurs, including necks heads, and bodies is in the process of enriching the models being designed for accurate simulation of their swimming habits, as the researchers describe on the website.
Fukuhara's group hopes that this new methodology can unlock new avenues of further exploration of the entire locomotion repertoires of other extinct animals.
