Ancient Proteins Discovered in 18-Million-Year-Old Mammal Enamel

In a groundbreaking discovery, paleontologists have identified protein sequences within the dense enamel tissues of ancient rhinocerotid and proboscidean fossils, dating back 18 million years, at sites located in the Turkana Basin of Kenya. This research, published on July 9, 2025, in the journal Nature, marks a significant milestone in the field of paleobiology, opening new avenues for understanding the biological and ecological history of extinct species.

The Turkana Basin, renowned for its rich fossil assemblages, offers a unique glimpse into the evolutionary past, housing fossils that extend over 66 million years. The recent study led by Dr. Daniel Green, a researcher affiliated with both Harvard University and Columbia University, involved the collection of powdered samples from the enamel of large herbivores. Dr. Green remarked, "Teeth are rocks in our mouths. They’re the hardest structures that any animals make, so you can find a tooth that is a hundred or a hundred million years old, and it will contain a geochemical record of the life of the animal."

Previously, it was believed that mature enamel contained minimal proteins due to its dense structure. However, advancements in proteomics, particularly the application of liquid chromatography tandem mass spectrometry (LC-MS/MS), have allowed researchers to detect a diverse range of proteins within these ancient tissues. Dr. Kevin Uno, also from Harvard and Columbia, explained, "The technique involves several stages where peptides are separated based on their size or chemistry so that they can be sequentially analyzed at higher resolutions than was possible with previous methods."

This study has revealed peptide fragments representing proteins that are as old as 18 million years, surpassing the previous oldest findings of 3.5 million years. Dr. Green noted, "Nobody’s ever found peptide fragments that are this old before. The newly discovered peptides cover a range of proteins that perform different functions, altogether known as the proteome."

In light of these findings, Dr. Emmanuel Ndiema, a researcher at the National Museum of Kenya, expressed enthusiasm about the implications for paleobiology. He stated, "This research opens new frontiers in paleobiology, allowing scientists to go beyond bones and morphology to reconstruct the molecular and physiological traits of extinct animals and hominins." The ability to analyze these peptides could facilitate the exploration of phylogenetic relationships among ancient species, even those lacking direct descendants.

The implications of this discovery extend beyond mere academic interest, potentially influencing fields such as evolutionary biology, ecology, and conservation. By understanding the molecular traits of extinct species, researchers can draw parallels with contemporary organisms, enhancing our knowledge of evolutionary processes and environmental adaptations.

The research team anticipates that these findings will stimulate further studies into the proteomic content of other fossilized remains, potentially illuminating the evolutionary history of various mammalian lineages. The significance of such discoveries underscores the importance of continued investment in paleontological research, particularly in biodiverse regions like the Turkana Basin.

In conclusion, the detection of ancient proteins from 18 million-year-old mammal enamel not only challenges previous assumptions about fossilized tissues but also paves the way for novel methodologies in paleobiological research. This transformative approach may redefine our understanding of the evolutionary narratives of extinct species and enrich our comprehension of biodiversity through geological time. The full details of this study can be found in the publication available online through Nature.