Paleontologists have unearthed fossil footprints from both invertebrates and vertebrates, dating back between 500,000 and 25 million years, including a faux Saber Tooth cat (Nimravid).
John Day Fossil Bed National Monument (Joda) is renowned in central and eastern Oregon for its ancient mammalian fossils.
Paleontologists indicate that these specimens provide a nearly continuous 50 million-year record of mammalian evolution.
Within the Joda, four geological layers are identified: Clarno (50-39 million years), John Day (31-25 million years), Muscoll (16-12 million years), and rattlesnakes (8-6 million years).
The recently uncovered footprints belong to the Clarno and John Day layers.
“These footprints reveal intriguing behaviors and species previously undocumented in the extensive fossil records of the monument,” the researchers stated.
The series of footprints in the 29 million-year-old volcanic ash layer of the John Day Formation may have been created by Nimravid, a saber-toothed predator comparable in size to a bobcat, Hoplophoneus.
The absence of nail marks supports the notion of retractable nails, akin to modern-day felines.
Additionally, three round hoof prints of the same age likely belong to large herbivores, such as ancient tapirs and rhinoceroses.
Two small bird impressions, as well as a beak mark and an invertebrate trail, were found in the Clarno Formation.
These findings suggest ancient shorebirds were foraging for food in shallow waters.
Connor Bennett, a paleontologist at Utah Institute of Technology, remarked:
“It’s captivating; such a long duration for a species to maintain foraging patterns as seen in its ancestors.”
Within the same layer, scientists discovered an unusual fossil track featuring scattered toe impressions.
This indicates that lizards breaking through the lakebed represent one of the few known reptile trajectories from this period in North America.
“These tracks provide a unique window into ancient ecosystems,” stated Dr. Nicholas Famoso, Joda’s paleontology program manager.
“They add behavioral context to the body fossils amassed over the years, enhancing our understanding of prehistoric Oregon’s climate and environmental conditions.”
“Fossil tracks not only confirm the presence of these animals but also reveal their lifestyles,” Bennett added.
The team’s survey results will be published in the journal Palaeontologia Electronica.
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Connor J. Bennett et al. 2025. Following their footsteps: Reports of vertebrate fossil tracks from John Day Fossil Bed National Monument, Oregon, USA. Palaeontologia Electronica 28(1): A11; doi: 10.26879/1502
Source: www.sci.news
