One of the studied animals was a fierce-looking, toothy beast known as Ichthyostega. It lived 374 – 359 million years ago and was a transitional species between fish and terrestrial animals.

Ichthyostega is thought to have navigated through shallow water in swamps, probably lured by food.

Now we know that it probably moved by dragging itself across flat ground, using its front legs to crutch itself forward, much like that of a mudskipper or seal.

The findings are published in the journal Nature.

Lead author Stephanie Pierce, of the University of Cambridge’s Department of Zoology, was quoted as saying in a press release, “The results of this study force us to re-write the textbook on backbone evolution in the earliest limbed animals.”