A rare and surprisingly well-preserved fossil of a giant turtle that lived between 10.8 and 8.5 million years ago during the Miocene was found in the Boca dos Patos region of Assis Brasil, Acre.
The discovery was done by a research group led by teachers and paleontologists Carlos D’Epolito Júnior, from the Federal University of Acre (UFAC), and Annie Schmaltz Hsiou, from the University of São Paulo (USP), coordinators of the “New Borders in the Fossiliferous Registry of the South-Western Amazon”, funded by the Scientific Expeditions Notice, the Amazon Initiative+10-Foundations Program-Foundations Program of Foundations Research Support State (CONFAP), with resources from the National Council for Scientific and Technological Development (CNPq), FAPESP and the Acre State Research Support Foundation (FAPAC).
“We found a carapace of the largest freshwater turtle that ever existed, the Stupendemys geographicus”, Hsiou says, who has been studying the region for almost 20 years. The carapace found was incomplete, from the waist, and was large, about 1.70 meters wide. The carapace is among the best preserved ever found of this species – a spectacular record of this surplus that lived during the myocene in the Brazilian Amazon. ”
The diversity of fossils of the Amazonian South West region has been known for over a century and a half and includes well consolidated along the barrancos and banks of the main rivers of the region, especially in the state of Acre. “The point is that we generally find very fragmented fossils,” explains D’Polito Jr. “It is common to find pieces of carapace, bone remains or rarely together and especially smaller animals, which are easier to stay articulated. Finding large animals, well preserved, was a surprise. Now it will be possible to compare with records from other places, such as Venezuela, we will be able. Finally, it is the same species or if there was a different one. ”
The researcher compares the discovery of other major reptiles found in the region, such as those in the Amazon. “It’s not exactly the same, of course, but in 1986 an entire skull was discovered Purussaurus brasiliensiswhich is a giant alligator, the largest that ever existed. And from this fossil some studies were done in relation to his description, the size estimate, the bite. I consider it a great comparative, precisely because they are reptiles who lived in the same region at the same time – a very different environmental period, warmer, much more available water, where you found gigantic lakes and rivers. ”
The geological time of the Miocene (23 million to 5 million years ago) is known for the rich aquatic and terrestrial fauna, as well as being the cradle of several Amazonian strains. “Therefore, the more we go deeper into this geological interval, the more we will understand how biodiversity was formed in the Amazon and how climate change caused extinctions and transformations in the region,” explains Hsiou.
Boca dos Patos Expedition
Fieldwork required great logistical effort. The team, made up of 16 people, with ten researchers, five boatmen and a cook, took a full day to climb and down the river until they reach the excavation site. “The dry river is the main difficulty. We were stopping a lot to push the boat until you found a little piece deeper and be able to navigate,” recalls D’Polito Jr. The expedition had a maximum period of six days, because the waters could be too lower and it would be even harder to return. “We were lucky, because this fossil was found on the first day,” celebrates the researcher.
The collection of the material lasted four days between excavation, preparation of plaster jacket for the preservation of the hull, removal and river transport to the city of Assis Brazil, about seven hours by boat from there – then to go to the Federal University of Acre, in the capital. “If we had not found in time, the material would have fatally lost. When it rains and the dry river bed floods, the water takes everything. There would be nothing or much less the preserved state we find the carapace,” projects the researcher.
The turtle was transported in a makeshift base made with wood cut by the boatmen, generally riverside and residents of the city of Assisi. Interaction with local communities, including, is one of the project axes. “The partnership with them is critical to discovering new fossils and new species that have never before been described-or that only the knowledge of traditional and original communities were aware. Now we can bring light on what really happened in proto-Yellow and also understand how these people’s relationships with fossils are like,” says Hsiou.
One of the proposals of the work is precisely to be linked to residents who have knowledge of fossiliferous localities and have acted as sources, giving them and their communities recognition, as well as training, on the preservation of regional paleontological heritage. “We already have a certain knowledge about the understanding of the indigenous of the upper river Juruá with the fossils,” says the researcher. “We know the respect they have to the fossils they find on the river’s Beira. There is a certain devotion to this material. Our intention is to further deepen environmental education and the awareness of the importance of preservation, both biodiversity and past. They are the guardians of these places.”
During the expedition to the region of Boca dos Patos, there was also contact with the local indigenous community of the village of the Patos, the Manchineri people. “We went to ask for permission and show that we were there. We didn’t work on the indigenous land itself, but they went there to follow our excavation work,” says D’Polito Jr.
Next Steps
The fossil of Stupendemys geographicus He was transported to the headquarters campus of the Federal University of Acre, in Rio Branco, where he will undergo scientific analysis and then integrate Ufac’s fossil collection. One of the guidelines of the Scientific Expeditions Notice, by which the project “New Borders in the South-Western Amazon Fossiliferous Registry” is funded, it is precisely that the material collected in field work is cataloged and listed in Amazonian institutions, as a form of preservation of local heritage.
“Ufac’s collection has nearly 10,000 fossils and the vast majority has been discovered in close places. With the trip to more remote places, we increase the chance of finding materials that do not yet exist in the collection or, although already known, are better preserved and bring more taxonomic information. Thus we will better understand what the Amazon of the past, such as fauna and flora have evolved and adapted to changes climate ”, comments D’Polito Jr.
The objective of the project is to continue exploring other rivers in Acre and southern Amazonas, one of the main geological units within the Solimões Formation. “After this superrtoise, we are looking forward to finding much more interesting fossils in these more inhospitable and little explored places,” says Hsiou.
It also highlights the importance of cooperation between institutions. “I have a strong partnership with UFAC researchers. All my projects funded by FAPESP, since my first young researcher, deal with Fossils of Solimões Formation, Southwest of the Brazilian Amazon, or the Western Amazon,” he says. “We have already produced numerous scientific articles together and we have a great focus on human resources training, sharing research and materials and also exchanging students from USP and UFAC,” celebrates the researcher.
