A team of Brazilian scientists has discovered a fossilized skeleton of what they believe is one of the world’s oldest dinosaurs after heavy rains in the southern state of Rio Grande do Sul accelerated the natural process of erosion.
The fossil found next to a reservoir in the municipality of Sao Joao do Polesine is around 233 million years old, according to paleontologist Rodrigo Temp Müller, who led the team from the Federal University of Santa Maria that found the bones in May.
The claims have not been verified by other scientists or published in a scientific journal.
The researcher believes the dinosaur lived during the Triassic period, when all continents were part of a single land mass called Pangaea. Dinosaurs are thought to have first evolved at that time.
The apex predator discovered in Rio Grande do Sul belongs to the group known as Herrerasauridae — a family of dinosaurs that used to wander across lands that now make up present-day Brazil and Argentina, according to a fact sheet about the discovery shared with The Associated Press.
Rodrigo Temp Müller said that he and his team were “very excited and surprised” by their findings.
After around four days of excavations, the group of researchers transported a block of rock containing the specimen back to the laboratory, where they ran tests.
“Initially it seemed like just a few isolated bones, but as we exposed the material, we were able to see that we had an almost complete skeleton,” Müller said.
The expert hypothesizes that their discovery is the second most complete skeleton for this type of dinosaur.
Researchers will now try to determine whether the fossil belongs to an already-known species or a new kind. That work is expected to take several months, as the process is meticulous to ensure no damaged is caused.
Fossils are more likely to appear after rains, as water exposes the materials by removing the sediment that covers them, in a phenomenon known as weathering.
Rio Grande do Sul saw record amounts of rainfall earlier this year. That caused devastating floods in May that killed at least 182 people, according to a toll published by the state’s civil defense on July 8.
Extreme weather events are made more likely by climate change, principally caused by the burning of oil, gas and coal.
Müller said that more fossils are appearing because of the heavy rains, which has launched a race against time to rescue the materials before they are ruined.
In the field, his team observed “a leg bone and a pelvis bone in the pelvic region that were already being destroyed due to the rain,” he said.
Müller hopes the discovery will contribute to elucidate the origins of dinosaurs.
“Having new fossils that are so well preserved certainly helps us better understand this topic that is still much debated,” he said.