A Rich Collection of Triassic Fossils Found at Bears Ears

Monday, February 26, 2018

Paleontologists excavate a phytosaur fossil in what was Bears Ears National Monument in September 2017. The site turns out to harbor a rich deposit of Late Triassic fossils in the Chinle Formation.  (Photo courtesy of Robert Gay)

Paleontologist Robert Gay’s quest to find the fossilized remains of an ancient phytosaur, a primitive ancestor to crocodiles, turned into something much larger last summer when he came upon a major trove of Triassic fossils on public lands recently stripped from Utah’s Bears Ears National Monument.

But Gay’s find also is significant for other reasons that speak to the vulnerability of fossil deposits in Utah and elsewhere to looting and vandalism, especially those near roads like the site he dug with permission and funding from the Bureau of Land Management.

“This site [on the western side of the former monument] is pretty spectacular,” the scholar told The Salt Lake Tribune on Friday.

“It’s an entire bone bed, it is the largest and densest Triassic bone bed in the state of Utah. It is higher density than some of the more famous Jurassic sites,” said Gay, who presented his findings Feb. 16 at the annual meeting of the Western Association of Vertebrate Paleontologists in St. George.

“There are decades of work at this site,” said Gay, who called the deposits “the Triassic equivalent of Dinosaur National Monument,” famed for later Jurassic fossils.

Gay discovered articulated phytosaur remains, with fossilized bones found together, during survey work in 2016 in Chinle Formation, which dates back 217 to 223 million years. He returned the following September to recover the bones in a project conducted in conjunction with the Museums of Western Colorado.

But as Gay’s work progressed, he said, his team uncovered the front end of a ancient crocodile’s snout, but the cranium and neck were missing. Plaster residue clung to the sandstone, a tell-tale sign that someone had looted the site, said Gay, who serves as education director for the Colorado Canyons Association in Grand Junction.

He reported the theft to the BLM, which had some good news for him.

Nearly a decade earlier, the culprit had turned in the purloined skull, missing a snout, to Arizona’s Petrified Forest National Monument, according to Bill Parker, the monument paleontologist who received the skull. Parker had only recently transported the skull to BLM paleontologists in Moab, who in turn delivered it to the Natural History Museum of Utah for curation.

“It was complete serendipity that three weeks after I dropped it off, I got a call from the BLM saying they thought someone found the rest of it,” Parker said.

“It’s a good story because that doesn’t always happen,” he said.

In September 2008, the person who looted the fossil brought it to Parker after finding it in his garage. He admitted he excavated if from a particular canyon in San Juan County — without proper permits.

“I made a decision, because it was supposedly from BLM land, to accept it,” Parker said. “So he signed it over to us. I contacted Utah state geologist. At the time there was no proof of where it came from, the person wasn’t held. He has since moved on and who knows where they are.”

Information submitted by a BLM paleontologist to the St. George conference indicates the illegal excavator was a “volunteer at a major regional museum,” who turned in the specimen after partial preparation.

“This situation shows the need for increased education, monitoring, and protection around paleontological resources and highlights the vulnerability of fossil resources that remain un-excavated across the Bears Ears region,” the BLM report said.

It was only through a “rare combination of circumstances,” the BLM said, that the fossil’s origins were rediscovered. That, the report said, “is not the usual situation for looted fossils, which are often never recovered or recovered without their context, making this case a poignant reminder of what can be lost during looting.”

Parker and his colleague Larkin McCormack are preparing a paper on the stolen half of the specimen — believed to be from the ancient species Pravusuchus hortus — for scientific publication. In the meantime, he hopes the two specimens can be reunited, but that, it turns out, is easier said than done.

Gay’s specimen is currently undergoing preparation at St. George’s Dinosaur Discovery Site at Johnson Farm, which is helping manage the excavation. The bones will eventually be curated at the Museums of Western Colorado, which hopes to put them on display.

That organization, which has a paleontology museum in Fruita, wants to obtain the stolen half of the skeleton so the whole thing can be studied as a single unit.

“We are trying to figure out a way to keep the site and specimens together between our two museums,” said paleontology curator Julia McHugh. “There’s a lot of logistics and paperwork involved, so we haven’t quite nailed down how we are going to do that.”

“From the perspective of someone doing research,” McHugh said, “it’s not in their best interests to have the site divvied up between two museums.

She said she agrees the new Bears Ears fossil site is special and could shed new light on the Late Triassic, a period when some big reptiles went extinct and dinosaurs rose to rule the world during the Jurassic.

“It’s a really good site, has some good bone in it. It has some good diversity in it,” said McHugh, whose museum is also exploring Triassic sites in New Mexico. The Bears Ears locale appears to also harbor remains of an armored plant-eating crocodilian, known as aetosaur.

“One of the great things about the Late Triassic is you have a big turn over in ecosystems. You go from a world dominated by large amphibians, large crocodilian predators, herbivore, and you have the rise of dinosaurs coinciding with this,” McHugh said.

“As these lineages change over for who’s in charge of the ecosystem, you get a window into how evolution is working and how changes in climate are driving evolution,” she said. “Because we have a sporadic fossil record, any time we get a new site with a lot of good material, it’s really exciting because it is going to tell us things we don’t know yet.”

Conservationists have heavily promoted Gay’s discovery because it highlights what they say was the shortsightedness of President Donald Trump’s decision to shrink the Bears Ears monument, a move that is being challenged in court.

“While a discovery of this magnitude certainly is a welcome surprise, protecting such resources was the very purpose of Bears Ears National Monument,” said Scott Miller of the Wilderness Society, an environmental group.

“That President Trump acted to revoke protections for these lands is outrageous, and that he did so despite the Department of the Interior knowing of this amazing discovery is even more shocking,” Miller said. “I hope the courts will act quickly to restore protections for Bears Ears National Monument before any more fossils are looted from the area and lost to science.”

Whatever the outcome of the court case, however, the fossils will remain under the jurisdiction of the Paleontological Resources Protection Act, a 2009 law that carries criminal penalties for those who loot fossils from public lands.

Source: www.sltrib.com