313 million years ago, a large lizard-like creature crawled on a coastal sand dune that is now Grand Canyon. After some time, a light dew moistened the tracks with cement in place and then the wind blowing sand buried them, preserving the animal’s claw marks for eons.
Paleontologists who study the trackway say they are the oldest recorded vertebrate tracks in Grand Canyon National Park. Tetrapods or four-legged animals left this set of tracks, with another set imprinted after a while. The second set of footprints was placed down after some sand deposited in the first set, and the researchers said that these prints may be of the same species.
These ancestors of modern reptiles lived in sand 250 million years ago. T rex, And they must have gone using a highly developed gait.
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Norway geology professor Alan Krill initially explored the inscribed tracks in 2016, while leading his students on the annual field trip to the Grand Canyon along the Bright Angel Trail. He noticed that on the footpath there are fossilized footprints engraved in a fallen boulder at the base of a valley. Krill took print photos and sent them to a geologist, Steve Rowland, who often accompanied his group to Norway.
Roland and his team determined that the track-bearing boulder fell from a nearby cliff-risk Desired formation. “We were able to determine whether it was from that area because we studied features such as the nature of the rock, its color and grain size,” he said. Researchers allowed the tracks to date after knowing the origin of the rock.
Researchers said that the size of the tracks is about 15 to 30 inches (or 40 to 80 centimeters) long, the size of a chakwal.
When Roland’s team examined the tracks, they found two surprising features. “The first is that they are the oldest known amniote living in sand dunes,” said co-author Steve Rowland, Emeritus Professor of Geology at the University of Naval Las Vegas. Amniotes are animals such as birds and reptiles whose eggs can survive outside the water. Pre-developed species such as fish and amphibians are required to lay their eggs in the water. “Roland said,” finding these coastal locations meant that coastal reptiles meant that these ancestors of modern reptiles landed almost as they evolved.
Rowland told Live Science, “The other surprising thing is the arrangement of the footprints — these tracks revealed a lateral-sequence move.” If you see your pet dog or cat, especially when they are moving slowly, you can see that it will use lateral-sequence moves, in which they move the right-back foot forward-backward. Let’s move forward, and then left-backward to the left. This sequence is more stable than other known types of git, which are called diagonal-sequence driven, Roland said. Humans use this diagonal type of movement, swinging our left arm synchronously with our right leg, and vice versa. Fish also use a diagonal sequence when shaking their wings.
Four-legged animals can use both types of gait. “Until we study these tracks,” Roland said, “no one knew how quickly lateral-sequence moves came into use in animal history. Now, we know that in 313 million years It was used much earlier in the history of amniotes. Earlier. ”
Spencer Lucas, a paleontologist at the New Mexico Museum of Natural History, who was not involved in the study, praised the work. Current research, he said, documents “an important discovery: the earliest record of the footprints of tetrapod vertebrates in an Iolian (wind-formed) rock layer. This establishes that vertebrates lived in the desert millions of years earlier than previously Were. ”
The findings were published in the journal on 19 August one more.
Originally published on Live Science.