New Delhi: Researchers from Colorado have uncovered a fossil mammal about the size of a muskrat that lived in the time of the Dinosaurs. The mammal was identified on the basis of fragmented remains, a piece of a jawbone and some teeth. The creature lived between 70 and 75 million years ago, when a vast inland sea covered vast swathes of the American West. The creature has been named Heleocola piceanus, with the Genus name translating to ‘swamp dweller’ in Latin. While Colorado is famous for its fossil finds, the discovery of mammals from the time of the dinosaurs is rare.
3D scans of the jawbone of H. piceanus. (Image Credit: Eberle et al, 2024, PLOS ONE).
Considering the other mammals that lived in the Late Cretaceous period, H. piceanus is on the larger side. The discovery of the mammal has allowed scientists to get a fuller understanding of the ancient ecosystems in the region. The fossil hunters have been visiting the same region for about 15 years. The location is rich in the fossils of semiaquatic species such as turtles, duck-billed dinosaurs and massive crocodiles, that would have flourished around marshes and estuaries, feasting on vegetation and fish. The remains of sharks, rays and guitarfish have also been recovered in the region. The newly described fossil was originally uncovered in 2016, and with the jawbone measuring about an inch long.
Mammals in the age of dinosaurs
The mammals in the age of dinosaurs were quite small, about the size of rats, and are mostly identified by the remains of their teeth. H. Piceanus was much larger, about the size of modern-day mammals. The teeth of the creature indicated that it lived on a diet of plants, with a few insects and other small animals. A paper describing the findings has been published in PLOS ONE. One of the authors of the study, Jaelyn Eberle says, “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.”
