Paleontologists have extracted ancient enamel protein sequences from fossilized teeth of epiacaratherium sp., a nasal bacteria that thrived in the High Arctic of Canada between 240 and 21 million years ago (early Miocene). This recovered sequence enabled researchers to ascertain that this ancient rhino diverged from other syoxidants during the mid-Eocene Oligocene period, approximately 410-250,000 years ago. Additionally, the findings illuminate the distinctions between two principal subfamilies of rhinocerotinae and Rhinocerotinae, indicating a more recent division of bone development around 340-22 million years ago.
Reconstruction of three extinct rhinoceros species: foreground features a Siberian unicorn (Elasmotherium sibiricum), accompanied by two Merck rhinos (Stephanorhinus kirchbergensis); In the distant background is a wooly rhino (Coelodonta antiquitatis). Image credit: Beth Zaiken.
Dr. Mark Dickinson and his team from York University investigated the teeth of epiacaratherium sp. They utilized a method known as chiral amino acid analysis, which aids in understanding how these proteins were preserved over time.
By assessing the degree of proteolysis and comparing it with previously studied rhino material, they confirmed that the amino acids originated from the teeth themselves, not from subsequent contamination.
“It’s astounding that these techniques allow us to revisit the past and delve deeper,” Dr. Dickinson remarked.
“Armed with our understanding of ancient proteins, we can now pose intriguing new questions regarding the evolution of ancient life on Earth.”
The rhinoceros holds particular significance as it is currently categorized as an endangered species. Exploring its extensive evolutionary history offers vital insights into how past environmental shifts and extinctions have influenced present biodiversity.
Historically, scientists have depended on the morphology of fossils or, more recently, ancient DNA (aDNA) to reconstruct the evolutionary narratives of long-extinct species.
Nonetheless, aDNA typically does not last more than a million years, constraining its utility in unraveling deep evolutionary history.
Although ancient proteins have been detected in Miocene fossils, previous samples extending back over 4 million years had been constrained to roughly the last 10 million years—full sequences were necessary for robust reconstructions of evolutionary lineages.
The latest research significantly broadens this temporal scope, indicating that proteins may endure across extensive geological timescales under optimal conditions.
“Success in analyzing ancient proteins from such old specimens provides fresh perspectives for scientists globally, who possess remarkable fossils in their collections,” stated Dr. Fazeera Munier of York University.
“This crucial fossil aids our understanding of the distant past.”
The results were published in the journal Nature this week.
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RS Patterson et al. Phylogenetically significant proteins from the early Miocene era. Nature Published online on July 9, 2025. doi:10.1038/s41586-025-09231-4
Source: www.sci.news
