For paleontologists, there is a shortage of fossils for tracing the evolutionary history of the Amazon region, a place that boasts unparalleled biodiversity. By drawing on new data collected at a site that has been known for over a century, the University of Fribourg researcher Juan Carrillo and colleagues from other institutions have made exceptional discoveries that shed new light on this poorly understood past.

The tropical rainforest of the Amazon possesses incredible biological diversity, the result of an extremely long history punctuated with significant variations in climate and landscape. Like all tropical regions, the Amazon has a sheer quantity of different plant and animal species that is higher than in other regions of the world. Fossils can help us trace this evolution back in time, but in the tropical countries of South America, fossil sites that have been studied in depth are rare.

An exceptional site for fossil hunters
Rare, but not inexistant! What is now called the Tatacoa Desert in Colombia is home to a fossil-rich site that is well known to paleontologists called La Venta. There researchers have uncovered fossils in an exceptional state of preservation dating back between 13 and 11 million years. Displaying great variety of fauna, these fossils attest to the existence of a tropical forest long ago. At the time, the northern Andes had not risen yet and the climate was considerably warmer than today.

Known but little studied
Paleontologists have known about the Tatacoa Desert site for over a century, although the last significant expeditions date back several decades. Recently, an interdisciplinary group of researchers from both Colombian and international institutions, including Juan Carrillo of the University of Fribourg, has revived paleontological interest in the site, closely collaborating with the local community of La Victoria, a small rural town of around 3000 inhabitants.

New discoveries
Combing through the site has enabled the paleontologists to make extraordinary new discoveries, such as the oldest relative of the Amazon river turtle, an ancient species of catfish, and the remarkable fossil of an extinct saber-toothed marsupial. The results show that despite a century of research, there remains a lot to learn from the La Venta site. This will help scientists to understand how changes in climate and geological events like the Andean uplift have influenced the evolution of tropical biodiversity.

An impact both scientific and local
Thanks to the joint work of scientists and young leaders from the local community of La Victoria, a museum was recently founded. It is contributing to the development of tourism in the town while also filling a number of educational missions. This is of great importance to protecting and studying the heritage of the world’s ancient past.
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CARRILLO J. D. (ed.) 2023. — Neotropical paleontology: the Miocene La Venta biome. Geodiversitas, vol. 45, arts 3, 6, 10, 12, 13, 15, 18, 25, 26.

Illustration credit: Guillermo Torres. Banco de Imágenes Ambientales (BIA). Instituto de Investigaciones de Recursos Biológicos Alexander von Humboldt.