Analysis of ancient proteins throws a new light on the genealogical tree of the rhinoceros
Paleontologists have recovered the old sequences of enamel protein from a fossilized tooth of Epiacatherium Sp., A rhinocerotis that lived at the top of the Arctic of Canada 24 to 21 million years ago (early Miocene). The recovered sequences allowed researchers to determine that this former rhinoceros diverged other rhinoceroids during the time of the Middle Eocene-Oligocene, about 41 to 25 million years ago. The new data has also shed new light on the divergence between the two main rhino underfamilies, Elasmotherinae and Rhinocerotinae, suggesting a more recent split in oligocene, around 34 to 22 million years, than that previously by bone analysis.
The reconstruction by a paleoartist of the three species of extinct rhinos: in the foreground is a Siberian unicorn (Elasmotherium sibiricum), and near behind are two Merck rhinos (Stephanorhinus kirchbergensis)); In progress, a woolly rhinoceros (Antiquity of Coelodonta). Image credit: Beth Zaiken.
Dr. Marc Dickinson of the University of York and his colleagues analyzed a tooth of Epiacatherium Sp. Use of a technique known as the Chiraux Amino Acids to better understand how proteins inside had been preserved.
By measuring the extent of the degradation of proteins and comparing it to the material of rhinoceros previously analyzed, they were able to confirm that the amino acids were original to the tooth and not the result of subsequent contamination.
“It is phenomenal that these tools allow us to explore more and more over time,” said Dr. Dickinson.
“Based on our knowledge of old proteins, we can now start asking new fascinating questions about the evolution of ancient life on our planet.”
The rhinoceros is of particular interest because it is now classified as an endangered species, and therefore understanding its evolutionary history in deep time, allows us to better understand how environmental changes and past extinctions have shaped the diversity that we see today.
To date, scientists have relied on the form and structure of fossils or, more recently, old DNA (ADNA) to reconstruct the evolutionary history of long species.
However, Adna rarely survives beyond a million years, limiting its usefulness to understand the deep evolving past.
While the old proteins have been found in the Fossils of the Middle Miocene – about the last 10 million years – obtaining sufficiently detailed sequences for robust reconstructions of evolutionary relations was previously limited to samples no more than four million years.
The new study considerably widens this window, demonstrating the potential of proteins to persist on large geological time ladders in the right conditions.
“A successful analysis of old proteins from such an old sample gives a new perspective to scientists from around the world who already have incredible fossils in their collections,” said Dr. Fazeelah Munnir, also from the University of York.
“This important fossil helps us to understand our old past.”
The results were published this week in the journal Nature.
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RS Paterson and al. Phylogenetically informative proteins of an early miocene rhinoceroid. Naturepublished online on July 9, 2025; DOI: 10.1038 / S41586-025-09231-4
