9-Million-Year-Old Capybara Tooth Reveals Ancient Wet Atacama Desert
- Scientists discovered a fossilized capybara tooth from almost 9 million years ago in Chile’s Atacama Desert, challenging the longstanding view that the region has remained continuously dry for...
- Researchers recovered the specimen from a three-foot-thick sediment bed at El Morro in northern Chile.
- Microscopic plant traces preserved within the sediments, known as phytoliths, indicate that palms and other flowering plants, including dicots, grew in the area.
Scientists discovered a fossilized capybara tooth from almost 9 million years ago in Chile’s Atacama Desert, challenging the longstanding view that the region has remained continuously dry for an estimated 40 million years. Described in a study published in Scientific Reports, the discovery provides the first and oldest record of the world's largest living rodent in coastal Chile, indicating that the parched region once featured a much wetter environment capable of supporting a stable ecosystem.
Discovery of the Fossilized Tooth in Northern Chile
Researchers recovered the specimen from a three-foot-thick sediment bed at El Morro in northern Chile. The sediments accumulated in a shallow sea between 10 million and 7 million years ago. El Morro is part of the Bahía Inglesa Formation, a fossil-rich area that also contains Cerro Ballena, known as Whale Hill, which is recognized as the world’s largest concentration of whale fossils. No other capybara remains this old have been found in Chile. Local residents had previously recovered fossils from the location and sold them to collectors, though some specimens were eventually donated to local scientists. Alongside regional specialists, the site was investigated by Carolina Gutstein, a professor at Universidad Santo Tomás in Santiago and the head of paleontology at the Chilean mining firm Fosfatos de Caldera. Priscilla Martinez, lead author of the study and a doctoral student in the University of Arizona’s Department of Geosciences, described the find just freakish
given the current extreme aridity of the location.
Ancient Palms and Freshwater Ecosystems
Microscopic plant traces preserved within the sediments, known as phytoliths, indicate that palms and other flowering plants, including dicots, grew in the area. Caroline Strömberg, a co-author and professor at the University of Washington, analyzed the botanical record. Think sunny Southern California full of palm trees,
Martinez stated, noting that the vegetation is entirely out of place in the modern Atacama. Additional support for a well-watered environment came from aquatic animal fossils found in the same deposits. Mark Clementz—who serves as a paleobiology expert, professor, and head of the University of Wyoming’s Department of Geology and Geophysics—pointed out that the sedimentary layers hold the remains of gavials, which are freshwater crocodiles, alongside freshwater fishes. All this supports the idea that there was enough of an ecological community to support capybara populations long term,
Clementz said. The presence of both freshwater species and semiaquatic herbivores demonstrates that the region offered sufficient water and vegetation to sustain permanent populations before the modern desert climate formed.
