Paleontologists have recently uncovered an exciting discovery in northwestern Colorado: an ancient mammal named Heleocola piceanus that lived around 70 to 75 million years ago, during the age of the dinosaurs.
The discovery sheds light on the environment where this creature thrived, which was a swampy area very different from the Colorado we know today.
According to the scientists, the region where H. piceanus lived was partially underwater, resembling modern-day Louisiana with its warm and wet conditions. ReBecca Hunt-Foster, a co-author of the study and a paleontologist at Dinosaur National Monument, described the habitat, saying, "We see a lot of animals that were living in the water quite happily, like sharks, rays, and guitarfish."
Heleocola piceanus: An Ancient Mammal from the Late Cretaceous
This indicates that H. piceanus was not alone; it shared its environment with various aquatic creatures.
Heleocola piceanus weighed around two pounds or more and was similar in size to a muskrat. Lead author Jaelyn Eberle, a professor at the University of Colorado Boulder, explained that this animal is a cousin to today's marsupials.
The researchers made this discovery by studying fossils found in the Williams Fork Formation in Rangely, Colorado, dating back to the mid-1980s, along with new fossils from 2018.
Originally, the fossils were thought to belong to other ancient species, but further research led to the exciting conclusion that they had found a new species.
This mammal's teeth suggest that it primarily ate plants but occasionally snacked on insects or small animals. Eberle noted that mammals from this time period are usually rare, which makes this discovery even more significant.
She expressed the importance of the find, stating, "Heleocola, which was an ancient opossum-like animal and a distant cousin to today's marsupials, is important, in part, because the time slice it comes from is not well documented in North America."
H. piceanus lived during the Late Cretaceous period when a vast inland sea, known as the Western Interior Seaway, divided North America into two landmasses. This ancient landscape was likely dotted with swamps, marshes, and coastal plains, providing a unique ecosystem for various creatures, including turtles and duck-billed dinosaurs.
The discovery of Heleocola piceanus highlights the significance of ancient mammals in understanding the ecosystems of the Late Cretaceous. While dinosaurs often steal the spotlight, findings like this remind us that there were larger mammals than previously thought, according to PLOS.
Eberle concluded, "They're not all tiny. There are a few animals emerging from the Late Cretaceous that are bigger than what we anticipated 20 years ago."
