A team of Paleontologists made a unique discovery that unearthed a fossil of a mammal that was the size of a muskrat, from a species that was believed to have lived during the time of the dinosaurs . The team led by paleontologist Jaelyn Eberle from the University of Colorado Boulder identified the fossil from the fragment of a jawbone and three molar teeth. Analysis from the recovered fossils was studied and published in the journal PLoS ONE . The fossil was identified to be from a period roughly 70 to 75 million years ago when a large part of Western America was submerged beneath an inland sea.
Paleontologists unearth 70-million-year-old ‘swamp dweller’ fossil in Colorado
The fossil was named Heleocola piceanus , a Latin phrase that meant “Swamp dweller.” This particular critter was excavated in 2016 from an area near Rangely, Colorado, which had also hosted several other fossil digs with successful results. Eberle, who was also the curator of fossil vertebrates at the CU Museum of Natural History commented, “Colorado is a great place to find fossils, but mammals from this time period tend to be pretty rare. So it’s really neat to see this slice of time preserved in Colorado,” according to Earth.Com . A slab of sandstone revealed under it the mammal’s jawbone and was witnessed by the co-author of the study John Foster, a scientist at the Utah Field House of Natural History State Park Museum.

Knewz.com noted that the name of the fossil was given based on the slab beneath which it was discovered, as it contained traces of swamps and river channels. Hence the species could have survived in an area that was a low-lying swamp. The area could have been home to various creatures that were native to such environments like turtles, duck-billed dinosaurs, and giant crocodiles, who inhabited marshes and estuaries, as mentioned in a statement to Newsweek . Though certain assumptions were made, researchers are yet to detail findings about the Heleocola, however, based on dental morphology, certain data about the swamp dweller’s livelihood could be discerned.
“Diet-wise, and based on its teeth, Heleocola was probably a plant-dominated omnivore, meaning it ate mostly plants but probably consumed some insects and/or small vertebrates too,” said Professor Jaelyn Eberle to IFLScience . “It’s a large mammal by Late Cretaceous standards (with an estimated body mass similar to today’s muskrat), whereas most mammals living at this time (70 – 75 million years ago) were mouse to rat-sized,” they added. CU Boulder Today stated that scientists had considered the size of this mammal to be insignificant until this discovery as it was not before the asteroid killed the non-avian dinosaurs 66 million years ago that this mammal increased in size. With the new find, researchers gained proof of life that was much bigger than scientists had previously anticipated it to be.

Though attention to this period was mostly reliant on dinosaur history, the Heleocola discovery was proof to establish the importance of ancient mammals in the process of understanding a region’s beginnings and the ecosystems of the Late Cretaceous period. It was also marked as a study into prehistoric Colorado, which cemented the significance of the area’s rich paleontological heritage and the need to preserve the location. Researchers urged people who came across any fossil findings to be mindful of their steps in documentation and information; and contact appropriate authorities to not tamper with the region’s identity and history, to protect it for generations to come.

Dana B
Thank you for sharing this information. I had not seen this article and it’s fascinating insight into early mammals during the age of the dinosaurs.