New Giant Dinosaur Species Found Beneath Brazilian Construction Site

Researchers have described a new species of giant dinosaur, Dasosaurus tocantinensis, after its fossils were uncovered during construction of a road-rail terminal in Davinópolis, a city in Maranhão state in northeastern Brazil. The species is described in a study published in the Journal of Systematic Palaeontology, the study of fossils and ancient life. The animal measured about 20 meters long and lived roughly 120 million years ago, during the transition from the Lower to the Upper Cretaceous period.

The fossils were found about eight meters underground by archaeologists monitoring the site under environmental licensing requirements, and were initially mistaken for remains of prehistoric mammals. Elver Luiz Mayer, a professor at the Federal University of the São Francisco Valley (UNIVASF), recognized the bones as much older from their depth and the known age of the rock layer. The specimen — including tail vertebrae, a 1.5-meter femur, ribs and limb bones — is unusually complete and is now held in São Luís, Maranhão's state capital.

Dasosaurus tocantinensis is the largest dinosaur known from Maranhão, where previously identified species, such as the roughly 10-meter-long Amazonsaurus maranhensis, were considerably smaller. Its closest known relative lived in what is now Spain, suggesting the two animals belonged to a broader lineage spanning regions now separated by the Atlantic Ocean. Researchers propose that ancestors of Dasosaurus tocantinensis reached South America via North Africa between 140 and 120 million years ago, when the landmasses were still joined within the supercontinent Gondwana.

Researchers are now negotiating with the construction company for permission to return to the site, where they believe more fossils from the same animal remain buried.