Skip to main content

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

Comments

Popular posts from this blog

The difference between Lion and Tiger skulls

A quick divergence from my usual dinosaurs, and I shall talk about big cats today. This is because to my greatest delight, I had discovered today a wonderful book. It is called The Felidæ of Rancho La Brea (Merriam and Stock 1932, Carnegie Institution of Washington publication, no. 422). As the title suggests it goes into details of felids from the Rancho La Brea, in particular Smilodon californicus (probably synonymous with S. fatalis ), but also the American Cave Lion, Panthera atrox . The book is full of detailed descriptions, numerous measurements and beautiful figures. However, what really got me excited was, in their description and comparative anatomy of P. atrox , Merriam and Stock (1932) provide identification criteria for the Lion and Tiger, a translation of the one devised by the French palaeontologist Marcelin Boule in 1906. I have forever been looking for a set of rules for identifying lions and tigers and ultimately had to come up with a set of my own with a lot of help...

Old drawings: Allosaurus

Recently, I came across a stash of old drawings that I had completely forgotten about. I'll try and upload them in the next week or two. Some are palaeo, others are not, but still quite interesting nonetheless... Here is the first. I think it is an Allosaurus head. At least the skull looks like an Allosaurus and it has lacrimal horns like an Allosaurus , so it must be an Allosaurus . Nothing special I guess...

R for beginners and intermediate users 3: plotting with colours

For my third post on my R tutorials for beginners and intermediate users, I shall finally touch on the subject matter that prompted me to start these tutorials - plotting with group structures in colour. If you are familiar with R, then you may have noticed that assigning group structure is not all that straightforward. You can have a dataset that may have a column specifically for group structure such as this: B0 B1 B2 Family Acrocanthosaurus 0.308 -0.00329 3.28E-05 Allosauroidea Allosaurus 0.302 -0.00285 2.04E-05 Allosauroidea Archaeopteryx 0.142 -0.000871 2.98E-06 Aves Bambiraptor 0.182 -0.00161 1.10E-05 Dromaeosauridae Baryonychid 0.189 -0.00238 2.20E-05 Basal_Tetanurae Carcharodontosaurus 0.369 -0.00502 5.82E-05 Allosauroidea Carnotaurus 0.312 -0.00324 2.94E-05 Neoceratosauria Ceratosaurus 0.377 -0.00522 6.07E-05 Neoceratosauria Citipati 0.278 -0.00119 5.08E-06 Ovir...