Paleontologists from Denver Museum of Nature & Science, Kent State University, the University of Michigan and City University of New York have discovered the fossilized remains of a mammal species which walked the Earth some 65.5 million years ago.
Life reconstruction of Militocodon lydae. Image credit: Denver Museum of Nature & Science.
The newly-discovered species was part of Periptychidae, a group of animals that gave rise to all modern hoofed mammals, including deer, cows and pigs.
Named Militocodon lydae, the ancient creature was roughly the size of a chinchilla, weighed between 270 and 460 grams, and likely had an omnivorous diet.
It lived in what is now the United States around 610,000 years after the end-Cretaceous mass extinction.
“Rocks from this interval of time have a notoriously poor fossil record and the discovery and description of a fossil mammal skull is an important step forward in documenting the earliest diversification of mammals after Earth’s last mass extinction,” said Dr. Tyler Lyson, curator of vertebrate paleontology at Denver Museum of Nature & Science.
The fossil skull and jaws of Militocodon lydae were discovered in the Corral Bluffs area in the Denver Basin, Colorado, the United States.
“Corral Bluffs is located east of Colorado Springs, Colorado, and is situated within the Denver Basin,” the paleontologists said.
“The south-facing arc of exposures that make up Corral Bluffs are part of the D1 sequence of the Denver Formation, which spans the uppermost Cretaceous through lower Paleocene.”
Militocodon lydae provides important clues about the explosive diversification of mammals in the wake of the dinosaur extinction.
“How and when life rebounded in the aftermath of the extinction of the dinosaurs has been shrouded in mystery due to a poor fossil record.”
“But thanks to an extraordinary discovery of remarkably complete fossils from Corral Bluffs, we are now able to paint a vivid picture of how and when life rebounded after Earth’s darkest hour.”
The study was published in the Journal of Mammalian Evolution.
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L.N. Weaver et al. 2024. Skull of a new periptychid mammal from the lower Paleocene Denver Formation of Colorado (Corral Bluffs, El Paso County). J Mammal Evol 31, 16; doi: 10.1007/s10914-024-09716-5