Fossilized Tooth Revealed Ancient Atacama Freshwater Ecosystem
A discovery from 8.8 million years ago indicates that Chile's hyper-arid region once supported semiaquatic wildlife.
Updated on Sept. 18, 2026 in Geography
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Researchers identified a fossilized tooth belonging to the genus Cardiatherium in the Bahía Inglesa Formation of the Atacama Desert. The find confirms that the region supported freshwater ecosystems during the late Miocene, despite the desert being hyper-arid for 40 million years.
Why it matters
This discovery provides critical insight into the environmental evolution of South America by demonstrating that previously arid zones were once habitable for semiaquatic animals. The findings challenge current models of regional ecosystem connectivity during the Miocene epoch.
The fossilized tooth from the genus Cardiatherium dates back 8.8 million years. This discovery suggests a significant environmental shift compared to the 40 million years of hyper-aridity characterizing the Atacama Desert.
The players
Cardiatherium
An extinct genus of semiaquatic rodents related to modern capybaras.
The details
Researchers identified the tooth through analysis of sediment layers within the Bahía Inglesa Formation, a site primarily characterized by shallow marine environments. The presence of associated fossils, including palms and flowering plants, confirms the existence of local freshwater habitats. Cardiatherium were semiaquatic rodents, requiring consistent access to water sources not present in the region today.
Timeline
8.8 million years ago: The period when the Cardiatherium lived.
Late Miocene: The geological epoch when the region was significantly wetter.
September 2026: The month the study was published in Scientific Reports.
The Tech Race
This discovery follows a pattern set by the Scientific Reports geological paleontology research series by providing new evidence of ancient biodiversity in unexpected environments. It aligns with ongoing efforts to refine the timeline of South American environmental transitions during the late Miocene.
This finding updates the scientific understanding of regional climate history for researchers and enthusiasts tracking South American biogeography. It provides a new baseline for studies investigating the migration patterns of ancient semiaquatic species across the continent.
The takeaway
This discovery confirms that current desert landscapes are not permanent features, highlighting the dynamic nature of historical ecosystems. Researchers are now focused on mapping the ancient freshwater routes that allowed fauna to traverse modern Chile.
Further reading
For more context on the environmental history of the region, visit the Geography section.
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