Science

Fossil footprints reveal ancient crocodile that walked on two legs

Fossil footprints reveal ancie...
A scale drawing of the Batrachopus grandis
A scale drawing of the Batrachopus grandis
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A scale drawing of the Batrachopus grandis
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A scale drawing of the Batrachopus grandis
An artist's impression of Batrachopus grandis
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An artist's impression of Batrachopus grandis
The tracks made by Batrachopus grandis in South Korea
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The tracks made by Batrachopus grandis in South Korea
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A strange set of fossilized footprints has been discovered in South Korea. According to palaeontologists, they look an awful lot like crocodile tracks, except for one major difference – the stride is that of a bipedal animal. That led scientists to the conclusion that the ancient ancestors of crocodiles were walking around on two legs.

The discovery was made in the Jinju Formation in South Korea, in a layer of rock dating back to between 110 and 120 million years ago. There, researchers found a series of footprints each measuring between 18 and 24 cm (7 and 9.4 in) long. At a glance they resembled crocodile feet, with clear heel impressions left by the flat-footed way that crocs walk.

The tracks made by Batrachopus grandis in South Korea
The tracks made by Batrachopus grandis in South Korea

But there was a problem – no “hand” prints were found alongside them. The team says that the prints they do have are clear and well-formed, with fine details of toe pads and scales still preserved. That rules out two simple explanations: that the hind feet were stepping into the front footprints, or that the front prints just didn’t fossilize.

On closer inspection, the team noticed a few other weird things that indicated that these tracks weren’t made by any kind of crocodile that we know today.

“Typical crocodiles walk in a squat stance and create trackways that are wide," says Kyung Soo Kim, lead researcher on the study. ”Oddly, our trackways are very narrow looking - more like a crocodile balancing on a tight-rope. When combined with the lack of any tail-drag marks, it became clear that these creatures were moving bipedally.”

An artist's impression of Batrachopus grandis
An artist's impression of Batrachopus grandis

The team named the new creature behind the tracks Batrachopus grandis. That groups them in with the crocodile ancestor Batrachopus, while the grandis refers to the fact that this new animal is six or seven times bigger than others of its type.

Judging by the size of the prints, the team extrapolated the size of Batrachopus grandis. The animal would have had legs about as tall as adult human legs, and walked hunched over. From nose to tail it would have measured about 3 to 4 m (9.8 to 13.1 ft) long.

The research was published in the journal Scientific Reports.

Source: University of Queensland

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3 comments
jgb
Another 'Just so' evolutionary fable. According to the drawing, there is too much weight fore of the pivot point, making walking like that depicted impossible.
Nelson Hyde Chick
I wonder how preserved the animals we are driving to extinction during the anthropocene will be millennia from now?
WB
its' some fabolous story that sounds great.. that animal would be doing summersaults given the front weight distribution.