Efforts of local museum volunteers contribute to the discovery of fossil mammals | News

The discovery was based on the analysis of fossils collected over decades. The authors’ findings were published Wednesday in the journal PLOS ONE.

The discovery concerns a muskrat-sized cousin of modern marsupials that may have inhabited swamps about 70 to 75 million years ago, when a vast inland sea covered much of the West . The researchers named the mammal Heleocola piceanus. “Heleocola” roughly translates in Latin to “swamp dweller,” according to a CU press release.

The discovery is based on analysis of fossils discovered at four locations on Bureau of Land Management lands southwest of Rangely. The fossils include isolated teeth and the jaw fragment, all found in the Williams Fork geologic formation.

The discoveries date back to field expeditions led by J. David Archibald at San Diego State University in the mid-to-late 1980s and some were the result of more recent field work conducted by the authors of the study. That work included the 2016 recovery of a sandstone block by participants in an Appalachian State University paleontology field course, working with study co-author John Foster. He is a scientist at the Utah Field House State Park Museum of Natural History in Vernal and is a former curator of Western Colorado Museums.

“It’s a big slab of sandstone with a bunch of fossils in it,” Julia McHugh, director of paleontology at the Museums of Western Colorado, said of the block collected in 2016.

But it wasn’t until two years after it was collected that Tom Lawrence, a volunteer at the Museums of Western Colorado, discovered the jaw fragment while working on the block, which is part of the museum’s collection. The fragment is about an inch long and still contains teeth.

According to CU’s press release, when Foster first saw the jaw piece emerging from the sandstone, “I said, ‘Holy cow, that’s huge.’ »

McHugh said: “Many species of mammals are defined by the shape of their teeth, so teeth are very important in mammalian paleontology. »

She added: “With a jaw fragment, you have several teeth in a row. You’re not dealing with a lone tooth here and a lone tooth there, they’re kind of all together and you can see how they fit together here and there, so it provides a bunch of extra information.

Analysis of the teeth of the discovered mammal suggests that it probably fed on plants, but also on certain insects or other small animals.

According to the CU press release, the mammal may have weighed about 2 pounds, making it larger than most mammals from the Late Cretaceous period in which it lived. Eberle said in the release that not all mammals of that era were tiny.

“There are some animals emerging from the Late Cretaceous that are larger than we expected 20 years ago,” she said.

She added: “Colorado is a great place to find fossils, but mammals from this period tend to be quite rare. So it’s really cool to see this slice of time preserved in Colorado.

John Foster and ReBecca Hunt-Foster, another co-author of the study and a paleontologist at Dinosaur National Monument, have been digging up fossils in northwest Colorado every summer for about 15 years. Around the time the newly discovered mammal lived, animals like turtles, duck-billed dinosaurs and giant crocodiles could have thrived in and around marshes and estuaries, according to the release.

“The area could have looked like Louisiana,” Hunt-Foster said in the release. “We see a lot of animals that lived happily in the water, like sharks, rays and guitarfish.”

The new peer-reviewed study can be viewed and downloaded for free at https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0310948.

Eberle is happy to see the Rangely area getting attention with this discovery.

“It’s a small town, but, in my experience as a paleontologist, a lot of interesting things come out of rural environments,” she said in the release. “It’s nice to see western Colorado make an exciting discovery.”