The fossilized remains of a nearly 75 million-year-old “swamp dweller” have been discovered by paleontologists in northwest Colorado.
The University of Colorado team behind the discovery has been digging just outside Rangely, Colorado, for 15 years and recently unearthed one of its largest and most important finds. strange to this day: the jaw of a Heleocola piceanusor “vertebrate inhabitant of marshes”.
The swamp dweller looks just like its name suggests. It was a very rodent-like marsupial, about the size of a muskrat, that weighed up to two pounds. However, this size was actually relatively large compared to most Cretaceous mammals.
“They’re not all tiny,” Professor Jaelyn Eberle, curator of fossil vertebrates at the University of California Museum of Natural History, told University of Boulder Today.
“There are some animals emerging from the Late Cretaceous that are larger than we expected 20 years ago.”
Before an asteroid wiped out nearly all non-avian animals 66 million years ago, mammals generally fell on the smaller side, usually with statures similar to today’s rats and mice, Eberle said. For this reason, many are largely identified through fossilized teeth.
70 million years ago, Colorado was nothing more than an inland sea, with the land around it mostly made up of marshes and swamps. The fossil itself was discovered where land and sea would have met at the time.
The only inhabitants of the area, besides swamp dwellers, would likely have included traditional swamp creatures like turtles and enormous crocodiles.
“The region could have looked like Louisiana,” Rebecca Hunt-Foster, co-author of the study, told CU Boulder Today.
“We see a lot of animals that lived happily in the water, like sharks, rays and guitarfish.”
The discovery team celebrated thinking outside the box and sticking to digging in western Colorado for as long as they did.
“It’s a small town, but, in my experience as a paleontologist, a lot of interesting things come out of rural environments,” Eberle told CU Boulder Today. “It’s nice to see western Colorado make an exciting discovery.”
“We have scientists who come from all over the world specifically to study our fossils. We are really lucky.