Like Cheetahs, Ancient Ocean Creatures May Have Moved With a Gallop

The fastest animals on land are the cheselers. The salamanders run at a measured pace. The big difference between the two is how they move.

The forelimbs and hindlimbs of horses move in pairs, just like the forelimbs and hindlimbs of cheetahs. The left and right limbs of salamanders are moving in a symmetrical manner.

salamanders were thought to be the model for how the first animals moved. Over time, asymmetrical gaits like galloping and bounding were thought to have evolved in different species.

A new research shows that asymmetrical gaits existed in our jawed ancestors living over 400 million years ago in the ancient oceans. The Journal of Experimental Biology published the work on Tuesday.

Michael Granatosky, an evolutionary biologist, said that asymmetrical gaits underlie the speeds achieved by animals.

Evidence has been piling up to suggest that asymmetrical gaits may not have arisen as recently as was thought. At least one sea turtle species bounds underwater and there are fish that walk along the ocean floor.

The African lungfish has little spaghetti noodles for its legs, but they walk on the bottom of the substrate.

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The researchers were motivated to re-examine how asymmetrical movement evolved. The team built a tree of evolutionary relationships from a sample of jawed vertebrates. Each species was assigned a score of 0 if it could not move asymmetrically or a score of 1 if it could. They looked at a number of potential models to see which one best fit the data.

The model that turned out to be the most likely didn't put any restrictions on how asymmetrical gaits may have evolved, with gains and losses allowed to happen freely over time.

It showed a 75 percent likelihood that the ancestors of jawed vertebrates were the looser model.

This finding makes perfect sense to a Biologist at Temple University who was not involved in the study. It is evolving.

The holes in the analysis are not hidden.

It's a little bit of a guessing game when you're trying to estimate how long something has been dead. The research field has an extreme bias to how we sample data from non-mammalian species.

Although he acknowledges the study's potential blind spots, Pedro Godoy, an evolutionary biologist at Stony brook University who was not involved in the study, sees this work as an important contribution to understanding locomotion across species.