Newly discovered fossil remains from Maranhão state in northeastern Brazil belong to Dasosaurus tocantinensis, a previously unknown titanosauriform sauropod that reached approximately 20 meters in length and lived roughly 120 million years ago, according to a study published in the Journal of Systematic Palaeontology. Researchers state that its closest known relative inhabited what is now Spain, offering concrete evidence of an ancient biogeographical link between European island chains and South America during the Cretaceous period.
Discovery of the Giant Sauropod in Maranhão
The remains of Dasosaurus tocantinensis were uncovered during construction work on a road-rail terminal in Davinópolis, Maranhão. Archaeologists monitoring the site as part of the environmental licensing process initially suspected the material belonged to younger megafauna mammals. However, Elver Luiz Mayer, a professor at the Federal University of the São Francisco Valley (UNIVASF), noted the depth of about eight meters and recognized the geological formation from previous research as dating to the transition from the Lower to the Upper Cretaceous, roughly 120 million years ago.
According to Max Langer, a professor at the Ribeirão Preto School of Philosophy, Sciences, and Letters at the University of São Paulo (FFCLRP-USP), the find includes tail vertebrae, a 1.5-meter femur, ribs, foot bones, and arm and leg bones. “Because it includes tail vertebrae, a 1.5-meter femur, ribs, foot bones, and arm and leg bones, this is considered a relatively complete specimen,” Langer states, adding that the team believes more fossils from the same specimen remain buried at the site. The fossils were analyzed in Pará and later returned to Maranhão to be housed at the State Center for Natural History and Archaeology Research in São Luís.
Did you know? The name Dasosaurus tocantinensis derives from “Daso,” meaning forest in reference to regional woodlands, and “Tocantinensis,” pointing to the Tocantins River, as the fossil site lies near its eastern bank.
Evolutionary Links Between South America and Europe
Phylogenetic analysis reveals that the closest known relative of Dasosaurus tocantinensis inhabited the region that is now Spain. Researchers state that the ancestors of the Maranhão species likely migrated to South America through North Africa between 140 and 120 million years ago. At that time, these landmasses remained connected as part of the supercontinent Gondwana. This discovery indicates that specific bone remodeling and growth patterns emerged earlier in dinosaur evolution than previously understood, shedding light on how certain sauropods attained massive sizes.
Elver Luiz Mayer points out the distinction between this find and other regional discoveries. “It’s the largest known dinosaur for Maranhão, which has other species, but not sauropods like this one; rather, it has smaller ones, such as the diplodocid Amazonsaurus maranhensis, which was about 10 meters long,” Mayer explains.
Infrastructure Projects and Paleontological Preservation
The unearthing of Dasosaurus highlights the complex relationship between major construction projects and fossil preservation in tropical environments. Dense vegetation across Brazil often limits traditional hand-tool excavation, meaning paleontologists rely heavily on commercial and industrial earth-moving projects to expose deep rock layers.
“Brazil is a tropical country with dense vegetation. Geologists and paleontologists rely heavily on human activity to excavate, expose the rocks, and reveal the fossils,” Langer states. While highways and quarries provide crucial access to paleontological heritage, experts emphasize the necessity of regulatory compliance. “That’s why it’s urgent to foster closer cooperation between the parties to reconcile construction projects with federal legislation on fossils and promote new discoveries while ensuring the proper preservation of our heritage,” Mayer notes. The research team is currently discussing continued excavation work with the construction company.
Frequently Asked Questions
How old are the Dasosaurus tocantinensis fossils?
The fossils date back approximately 120 million years, placing them in the transition period between the Lower and Upper Cretaceous.
Where are the fossils currently housed?
After being analyzed in Pará, the specimen was returned to Maranhão and is kept at the State Center for Natural History and Archaeology Research in São Luís.
What makes this discovery significant for paleontology?
The find provides evidence of an ancient evolutionary link between South American sauropods and European relatives, while also offering insights into early dinosaur growth patterns and bone remodeling.
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