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Robotic salamander

I know this isn't about dinosaurs but it's more to do with scientific methods in palaeontology. Recently, in the journal Science, there was a paper about a robotic salamander where its gaits are controlled by a spinal cord model. The spinal cord model gives out signals that oscillates the trunk. The team confirmed that the more intense the signal, the higher the frequency of the oscillation gets. This higher frequency oscillation produces a swimming gait similar to that of real salamanders. On top of that, they found that limb oscillation saturates at a lower frequency and the robot switches from walking to swimming.

According to the authors, the main significance of this study is 'to show how a tetrapod locomotion controller can be built on top of a primitive swimming circuit and explain the mechanisms of gait transition, the switch between traveling and standing waves of body undulations, and the coordination between body and limbs'.

This work has been taken up pretty frequently as a possible scenario of evolution of walking gaits from swimming in early tetrapods. Though, I have heard criticisms that since salamanders are derived amphibians, modelling their locomotory switches from swimming to walking does not necessarily show how this might have happened in basal tetrapods. This is true from a certain perspective, like trying to figure out the biomechanics of basal birds (without all the adaptations of flight), using advanced birds (with highly specialised flight adaptations) as models. However, as the authors stated, the significance of this study is that the neural control of walking can be based on a primitive swimming neural control such as those seen in lampreys.

If this isn't convincing, then even from a purely biomechanical point of view, it is still significant in that they provided a good model to understand the locomotory switch from swimming to walking in a modern salamander. If we don't even understand how modern animals work, how are we to understand how extinct animals may have worked.

Originally posted on DinoBase

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