On the night of September 2, 2018, a fire raged through Brazil's National Museum, destroying the country's oldest scientific institution and one of the largest and most important museums in South America. On Tuesday, the museum announced that it had received a large donation of ancient Brazilian fossils to help rebuild its collection ahead of its planned reopening in 2026.

Burkhard Pohl, a Swiss-German collector and entrepreneur who maintains one of the world's largest private fossil collections, has given the National Museum around 1,100 specimens, all from Brazil. The donation is the largest and most scientifically significant contribution to date to the reconstruction of the museum after 85 percent of its approximately 20 million specimens and artifacts were lost in the fire.

The move also brings scientific treasures back to a country whose natural heritage has often disappeared outside its borders – and represents a potential global model for building a natural history museum in the 21st century.

“The most important thing is to show the world in Brazil and outside Brazil that we unite private individuals and public institutions,” said Alexander Kellner, the director of the National Museum. “We would like others, if possible, to follow this example and support us in this truly herculean task.”

Far more than the public exhibitions they house, natural history museums protect the world's scientific and cultural heritage for future generations. The 2018 fire destroyed the National Museum's entire insect and spider collections, as well as Egyptian mummies purchased by Brazil's former imperial family.

The flames also destroyed more than 60 percent of the museum's fossils, including parts of a specimen that scientists used to identify Maxakalisaurus, a Brazilian long-necked dinosaur. The newly donated fossils include plants, insects, two dinosaurs that may represent new species, and two exquisite skulls of pterosaurs, the flying reptiles that hovered above the dinosaurs' heads. The donation also includes previously studied fossils, including the enigmatic reptile Tetrapodophis, which was identified as a “four-legged snake” in 2015 but is now considered an aquatic lizard.

Dr. Pohl, who comes from a family of art, mineral and fossil collectors, said his donations were intended to ensure that Brazil's National Museum in Rio de Janeiro has a comprehensive and accessible collection of the country's fossil heritage.

“A collection is an organism,” said Dr. Pohl in an interview. “If it’s locked away, it’s dead; it has to live.”

The bones provide snapshots of life in what is now northeastern Brazil 115 to 110 million years ago, when the region was a lake-studded wetland that was frequently flooded by the young and growing Atlantic Ocean. Over time, these ancient waters gave rise to the Crato and Romualdo formations, limestone deposits in the Araripe Basin where quarries today dig for raw materials for cement production. Immaculately preserved fossils lurk among the rocks, some of which were formed when the bodies of creatures on ancient coastlines were quickly covered with microbial dirt and then buried. Crato fossils were flattened like pressed flowers; Romualdo fossils were buried in lumps of stone.

Since 1942, Brazil has treated fossils as state property and strictly prohibits their commercial export. But for decades, Brazilian fossils from the Crato and Romualdo Formations have circulated in the global fossil market and been sold in museum holdings and private collections around the world, including Dr. Pohl.

Brazilian paleontologists excited about the fossils' return to their homeland emphasized the research and educational opportunities they provide — and the positive precedent they could set for other donors. “It's very positive to maybe show some other collectors that things can be approached in a friendly way,” said Taissa Rodrigues, a paleontologist at Brazil's Federal University of Espírito Santo.

The foundation stone for Dr. Pohl's donation was made in 2022 when Dr. Kellner met Frances Reynolds, the founder of a Brazilian nonprofit arts organization called Instituto Inclusartiz. She quickly took on the mission of rebuilding the National Museum's collections, reaching out to a network of collectors to secure long-term loans and donations.

“If we can help people and we don’t, I can’t expect anything from anyone else,” Ms. Reynolds said. “It was a lot of work, but an incredible experience.”

Ms. Reynolds learned from Dr. Pohl's fossil collection through his son, the galleries of Dr. Pohls runs Interprospekt Group, a fossil and gemstone company based in Switzerland. Year-long negotiations followed and the fossils were shipped to Brazil in 2023; They will be housed in temporary accommodation until the main museum building is restored.

In addition to the fossils, the National Museum is working with the Interprospekt Group to conduct collaborative research across the United States. Last summer, a group of six Brazilian paleontologists and students traveled to Thermopolis, Wyoming, where Dr. Pohl maintains a private fossil museum. There, the Brazilian team will help search for fossils that could later be added to the National Museum's collections.

Dr. Kellner and Ms. Reynolds are actively soliciting donations and collaborations, and international institutions are responding to the call. Last year, the National Museum of Denmark donated a red cloak made from scarlet ibis feathers made by the Tupinambá people of Brazil, one of only eleven remaining artifacts of its kind in the world. The museum also works closely with Brazil's indigenous groups to rebuild the museum's ethnographic collections.

“This could be an important turning point,” said Dr. Waiter. “It really is something for the future of our people.”