Rock fall at Grand Canyon reveals ancient animal footprints

[Judi Lynn]

Felicia Fonseca, Associated Press
Updated 2:52 am CDT, Wednesday, August 26, 2020



Photo: AP
This undated photo provided by Grand Canyon National Park shows park employees Klara Widrig, left, and Anne Miller examining a rock that revealed fossilized footprints at the Grand Canyon in northern Arizona. Some researchers have estimated the footprints are 313 million years old, among the earliest found at the Grand Canyon. (Grand Canyon National Park via AP)

FLAGSTAFF, Ariz. (AP) — It's something like a modern-day chuckwalla, strolling in sand dunes on an island in what now is the Grand Canyon region.

That's how Steve Rowland, professor emeritus of geology at the University of Nevada, Las Vegas, and his fellow researchers interpret fossil footprints that were revealed in a rock fall near a popular Grand Canyon hiking trail. They estimate the tracks are 313 million years old, give or take a half-million years.


At that age, they'd be among the oldest tracks of animals that lay eggs with a protective hard or leathery shell and the earliest evidence of vertebrate animals walking distinctively in sand dunes, Rowland, Mario Caputo and Zachary Jensen wrote in a research paper published this month.

“I think our interpretations will hold up very well,” Rowland said Monday.

Not everyone is convinced the footprints were created by a single, four-legged animal that has a lateral-sequence walk, where the legs on one side of the body move in succession, followed by the legs on the other side. Or, that the footprints mark the point in evolution where animals were able to lay eggs with protective shells outside water.

More:
https://www.chron.com/news/article/Rock-fall-at-Grand-Canyon-reveals-ancient-animal-15511794.php