/https://public-media.smithsonianmag.com/filer/c9/94/c9947f05-f54c-4fc4-8ba7-549a2b7fcf76/01_ancient_footprints_manakacha-trackway-march-2018-46-adapt11901.jpg)
The 28 footprints capture an early reptile-like creature’s unusual diagonal gait (Courtesy of Stephen Rowland)
Posted on 10/29/2018 12:57:38 PM PDT by ETL
The 28 footprints capture an early reptile-like creature’s unusual diagonal gait (Courtesy of Stephen Rowland)
Some 310 million years ago, a reptile-like creature with an unusual gait roamed the sandy expanses of the Grand Canyon, leaving a trail of 28 footprints that can still be seen today. As Michael Greshko reports for National Geographic, these unusually well-preserved markers represent the national park’s oldest footfalls—and, if additional analysis links the early reptile to one that left a similar set of prints in Scotland roughly 299 million years ago, the tracks may even earn the distinction of being the oldest of their kind by more than 10 million years.
A paleontologist hiking the Grand Canyon’s Bright Angel Trail with a group of students happened upon the footprints in 2016. The animal’s path, which hardened into sandstone soon after its creator scurried off, had previously been hidden inside of a boulder. When the rock fell and split open, the winding trail was finally exposed, enabling the hikers to spot it as they explored the Arizona canyon.
The scientist reported the find to a fellow paleontologist, Stephen Rowland of the University of Nevada, Las Vegas, and in March of this year, Rowland and geologist Mario Caputo of San Diego State University arrived at the scene to investigate further. The pair announced their preliminary findings, soon to be followed up with a formal scientific study, at this month’s Society of Vertebrate Paleontology’s Annual Meeting.
According to Rowland and Caputo’s presentation abstract, the broken quartz boulder preserved the reptilian creature’s footprints as both impressions and natural casts measuring an overall width of about one meter across. Oddly enough, the tracks appear to represent a diagonal gait, as individual footfalls are angled 40 degrees out from the main pathway.
“Even if it was an ordinary trackway, it would be unusual,” Rowland tells Greshko. “But in this case, it’s doing a funny little side-walking step, line-dance kind of thing, which is weird.”
There are a number of potential explanations for the ancient animal’s strange gait. Perhaps a strong wind was blowing from the west, pushing the animal right as it attempted to push forward. Or maybe the creature purposefully angled its walk, hoping to steady itself on the slippery surface of a sand dune.
The creature may have been pushed to the right by strong winds
(Courtesy of Stephen Rowland)
It’s unclear what species the animal belonged to, but the scientists write that they “tentatively” assign the tracks to a “basal tetrapod of unknown taxonomic affinity” and the ichnogenus (category of trace fossil) Chelichnus, which is all basically a very science-y way to say we don’t quite know what this is, but we know it had four legs.
As researchers Patrick J. McKeever and Harmut Haubold explained in a 1996 article for the Journal of Paleontology, the Chelichnus classification was first used to describe a set of tracks found in Scotland’s Permian of Dumfries and Galloway during the early 19th century.
Unfortunately, McKeever and Haubold note, “Trackways that represent variations by the same trackmaker due to gait or substrate have been assigned different names. This practice has led to widespread confusion in the area of Permian vertebrate ichnology.”
Still, if Rowland and Caputo’s new identification proves accurate, the Grand Canyon footprints may well be the oldest left by members of the mysterious group.
“With a skeleton with bones and teeth, you get lots of good information, but you don’t actually see behavior,” Rowland says to Greshko.
Luckily, he concludes, “we’ve captured this animal walking.”
Exactly 310 million years old?
That’s what ended the dinosaurs. She flashed them.
Are they sure those aren’t ATV tire treads?
Or maybe a few hundred million fewer years than 310,000,000. It might also be the mud tire of a Jeep Wrangler.
310 million, 2 days, 4 hours, and 12 seconds.
Take this!...
Exactly, and not a day older or younger!!! snark, snark...
A big hole and a big ho........................
Mebbe he was sidestepping around those perfectly straight crossing lines so as not to mess them up?
Interactive geologic map of the Grand Canyon area:
http://rclark.github.io/grand-canyon-geology/
AZGS wunderkind Ryan Clark has built a demonstration interactive geologic map of the Grand Canyon region, using the geologic maps prepared by George Billingsley of the USGS.
Run your cursor over the map and the geologic unit name and description appear in the legend at the lower left. Although the maps were published at 1:100,000 scale, the original mapping was done at 1:24,000
That is so amazing. The world is truly a glorious place.
From the peculiar gate, it would appear to be the earliest discovery of Hillary Rodham’s decedents...
As predicted - thank you !
Thanks ETL. And yes, I do make my own fun, sometimes. :^)
If the Grand Canyon is, say, forty million years old and Ice Ages occur, say, every forty thousand years, then the Grand Canyon must have been covered with ice over a thousand times in its history. Odd that the Colorado River can leave its mark, but being covered by an ice pack a mile thick a thousand times -- for centuries at a time -- does not. [JoeSchem]
I am one of those weirdos who think the Grand Canyon was carved down in a much shorter time, and not so long ago.
From the air it looks so much like drainage from the huge ocean that was icebound in Canada and the Plains.
So, foot prints in mud at any level in the grand canyon is suspect in my mind.
Just my opinion. And I am a pretty hardcore traditional geologist guy from way back when Fossil Fred was teaching on the hill.
“Some 310 million years ago, a reptile-like creature with an unusual gait roamed the sandy expanses of the Grand Canyon”
The first dinosaurs are thought to have appeared somewhere around 225-235 million years ago.
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