A construction project in northeastern Brazil has uncovered a dinosaur that connects South American fossils with a relative from present-day Spain. The animal, named Dasosaurus tocantinensis, lived about 120 million years ago and reached roughly 20 meters long. It is now considered the largest known dinosaur from Maranhão state. The research was reported by Agência FAPESP.

What happened

The fossils were found in Davinópolis, Maranhão, while workers were building a road-and-rail terminal. Archaeologists were monitoring the project because environmental licensing required fossil checks. At first, the bones looked like the remains of large prehistoric mammals. Their depth changed that interpretation. The fossils lay about eight meters underground, inside a geological layer known to be about 120 million years old.

Elver Luiz Mayer recognized that the bones were much older than the team first thought. He contacted other specialists, who formed a group to study the specimen. The fossil was prepared and analyzed before returning to Maranhão. It is now kept in São Luís, the state capital.

What the bones show

The specimen is unusually informative. It includes tail vertebrae, ribs, foot bones, arm bones, leg bones, and a femur about 1.5 meters long. Researchers call it relatively complete, although much of the skeleton is still missing. More bones from the same animal may remain at the construction site.

The team also studied the internal structure of the bones. Its growth pattern combines features seen in older sauropods and titanosaurs. That result suggests some dinosaur growth and bone-remodeling patterns appeared earlier than scientists had believed. It may help explain how certain dinosaurs became extremely large.

Why Spain matters

The dinosaur’s closest known relative lived in what is now Spain. That relationship gives scientists a clue about how dinosaur groups spread across ancient lands. The team proposes that Dasosaurus ancestors reached South America through North Africa between 140 and 120 million years ago.

At that time, South America, Africa, and nearby regions were connected within Gondwana. The finding does not prove one exact travel route. It shows that the continents and land connections were different enough to allow related dinosaurs to live in places now separated by the Atlantic Ocean.

What remains unknown

The fossils cannot yet reveal the animal’s exact route, daily behavior, or full body shape. Scientists also do not know why this lineage had close relatives on both sides of the ancient Atlantic region. More bones could answer some of those questions.

What comes next

Construction can expose fossil layers that normal digging cannot reach. It can also damage or destroy those layers. The researchers are negotiating with the construction company for permission to return and continue excavating. Additional fossils could clarify the new species and the wider history of giant dinosaurs in South America.