The Atacama Desert in northern Chile is one of the driest places on Earth today. However, a fossil tooth indicates that parts of the region may have looked very different around nine million years ago.
Researchers identified the upper molar as belonging to Cardiatherium, an extinct genus of rodent related to modern capybaras. The discovery, reported in Nature, suggests that the area could once have supported wetlands, waterways and substantial vegetation.
The finding is particularly significant because capybaras are semi-aquatic animals that typically live near rivers, lagoons and wetlands. Their presence implies access to water, food and shelter in an environment that is now extremely arid.
“Finding a capybara tooth in a marine deposit in what is now one of the driest regions on Earth is simply astonishing,” said Priscilla Martínez, the study’s lead author and a doctoral student in the Department of Geosciences at the University of Arizona, according to a statement.
The researchers believe the animals may have reached the area through ancient river corridors and wetlands linking different parts of South America, although the exact route remains unknown. Co-author Bárbara Carrapa noted that there is no other evidence of capybaras from that coastal area of Chile, making the fossil an unexpected discovery.
The team also examined the sediment surrounding the tooth. The fossil was found in a layer preserving evidence of a shallow marine environment that existed between seven and 10 million years ago. Microscopic plant fragments known as phytoliths were also recovered, pointing to the presence of palms, grasses and other flowering plants.
According to co-author Mark Clementz, the evidence supports the existence of an ecological community robust enough to sustain capybara populations over a long period. Together, the tooth and plant remains provide a picture of an Atacama landscape that was far wetter and more biologically productive than it is today.
Sources: elDiario.es.