The Professor Pepe Paleontological Site, located in Parque dos Girassóis, in Presidente Prudente (SP), which was the target of complaints for possible irregularities, began to be excavated by a new group of researchers. The site brings together fossils of different species that lived between 80 million and 70 million years ago.
The interruption of work occurred after a civil inquiry was sent to the Federal Public Ministry (MPF) in 2023. However, the process was archived the following year, in 2024, after the body found no irregularities. Understand the process in this report.
Fieldwork began more than 20 years ago, led by paleontologist and professor William Roberto Nava. Currently, the area is fenced and has tall grass next to the fences and trash scattered across the land.
g1 was at the site last week and identified that the area is fenced and has signs indicating that littering is prohibited. Despite this, there was waste and vegetation accumulated along the fence.
A second, smaller plaque also identifies the space as the Professor Pepe Paleontological Site and informs that the site is part of the cultural heritage protected by:
Decree-Law No. 4,146/1942, of the Presidency of the Republic;
Law No. 10,267/2020, of Presidente Prudente City Hall;
Decree No. 30,661/2020, from Presidente Prudente City Hall.
In a note, the Mayor's Office of Presidente informed g1 that the excavations at the paleontological site follow a technical schedule defined and guided by researchers from the Universidade Estadual Paulista (Unesp) of Presidente Prudente.
The municipal administration also said that it follows this planning and, whenever communicated, meets the demands necessary to carry out field activities.
"The municipality promptly signed the agreement after it was drawn up, which was concluded later with the signing by the University. Even before formalization, the city hall was already taking measures to preserve the site and collaborating with research activities", states the statement.
Finally, the administration said that the site is permanently cleaned by the city hall, remains surrounded by fences and has identification and guidance signs, measures designed to prevent irregular waste disposal, vandalism and inadequate access.
Interruption of excavations
Professor William Nava continued excavations at the site until August 2023, when a complaint was made about possible irregularities related to the extraction of the fossils.
The case was forwarded to the Federal Public Ministry (MPF). According to the agency, the investigation was archived in 2024 and no irregularities were found during the investigations.
In a note to g1, the MPF reported that the foreign researchers involved in extracting the fossils had the appropriate authorizations granted by the National Mining Agency (ANM).
The agency also reported that the fossil material collected was destined for the Marília Museum of Paleontology and that no signs of diversion or illegal sale of the items were found.
Also according to the MPF, measures were adopted to preserve the Paleontological Site in Presidente Prudente, such as listing the site through Municipal Decree No. 30,661/2020 and fencing the entire area to prevent depredation.
“Since September 2024, the MPF has been carrying out an administrative procedure to monitor the effective adoption of measures to protect cultural heritage related to the paleontological site”, concluded the note.
According to William Nava, however, the excavations were interrupted at the beginning of the investigations and were not resumed later due to "a certain lack of incentive".
For the researcher, the interruption also represents the absence of new records and field collections that could contribute to scientific research.
“Our discoveries over all these years at this paleontological site in Prudente have placed the city in the global spotlight and have greatly contributed to the expansion of scientific knowledge in the area of paleontology”, reinforces the professor.
Discovery
To g1, the paleontologist, who is also responsible for the Marília Museum of Paleontology, recalled how he discovered the paleontological site. He was in Presidente Prudente in September 2004 to verify another fossil occurrence: that of a sauropod dinosaur, discovered in 2000 and named, in 2013, as Brasilotitan nemophagus.
“My attention was drawn to a hill nearby, which, as I approached, I saw a vacant lot with bushes, next to a group of small buildings, the CDHU, some rubbish and, on one side, on Av. Odinir Marangoni, there were rocks outcropping”, he recalls.
When checking the site, the researcher found small “bones” distributed in the rocky matrix, which, according to him, were “quite interesting”. From then on, he took blocks of rock to Marília to further his research.
In November and December 2004, William Nava continued expeditions there. In January 2005, he made a new discovery.
“Consulting the scientific literature, I identified that the small bones belonged to an extinct group of birds from the time of the dinosaurs, known as ‘enantiornithes’.”
From that moment on, the researcher continued working on the then vacant land, excavating and collecting small fossils found at the site.
“I focused my energies on this place, and it remained that way until 2017, when I began to rely, sporadically, on fellow researchers from other institutions who also helped with the excavations in search of more fossil materials that could be subjected to studies.”
According to the paleontologist, the bones of the birds found in Presidente Prudente corresponded to the first record of this group in Brazil, which is why they are considered rare.
Furthermore, the fossils of enantiornithes birds were well preserved. The material was analyzed and studied, resulting in the first scientific articles on fossil birds described from the Cretaceous period in Brazil.
“The degree of conservation of the fossils from the Pepe de Prudente site allowed scientists and paleontologists new glimpses and interpretations of the vertebrate fauna that inhabited what we now know as Oeste Paulista, around 80 to 70 million years ago, providing Brazilian paleontology with new knowledge and emphasizing its importance.”
Main findings
Among the main finds made at the Professor Pepe Paleontological Site are fossils of birds, lizards, crocodylomorphs, snakes, fish and dinosaurs.
“At the same time that bird bones were appearing, the excavations also turned up fossils of other animals, such as carnivorous dinosaur teeth, crocodylomorph teeth, coprolites (fossilized excrement), fish scales and other fossils”, he recalls.
In 2018, during laboratory work at the Marília Museum of Paleontology, William Nava claims to have identified a bird skeleton found at the Presidente Prudente site that also had the skull.
The discovery resulted in the publication of a study in one of the most prestigious scientific journals in the world. The material was named Navaornis hestiae, in reference to the researcher's surname.
“It was the first record of a fossil bird in Brazil to present the skull preserved in 3D (in fact, it is the first bird skeleton with a skull in Brazil, it is not found anywhere else) and was named Navaornis hestiae, in the magazine Nature, 2024, a simple tribute that the authors of the article made, and which made me very happy.”
Crocodylomorph eggs
In 2020 and 2021, during the pandemic, William Nava worked at the site accompanied by prudent geologist Giovanna Paixão.
The duo discovered the first clutches of fossilized crocodylomorph eggs in the Presidente Prudente region. The study on the material was published this year.
According to Nava, around 83 eggs grouped into three clutches were found, as well as isolated eggs.
“Studies revealed that this is the largest clutch of crocodylomorph eggs in the world, bringing together around 83 eggs grouped into three clutches, apart from the isolated eggs we found, revealing that this area of the Prof. Pepe site could have been, between 80 and 70 million years ago, a nesting site for these reptiles.”
According to the professor, other eggs, which have different morphologies, are being studied at the Federal University of Pampa, in Rio Grande do Sul, with the participation of Giovanna, who is also an intern at the Marília Museum of Paleontology.
The work carried out at the Professor Pepe Paleontological Site also included the partnership of researchers from other institutions, including professor Rodrigo M. Santucci, from the University of Brasília; professor Luis Chiappe, from the Natural History Museum in Los Angeles, in the United States; and professor Agustin Martinelli, from the Argentine Museum of Natural Sciences in Buenos Aires, Argentina.
“They were super important in the study and analysis of fossils, especially birds", says professor William Nava.
Prehistoric snake
In another fieldwork, carried out in 2020, researchers found the fossil of a snake, which was taken to the laboratory of the Marília Museum of Paleontology for study.
According to the researcher, the analysis revealed an almost complete skeleton, including the skull. The material was considered the first fossil snake skull found in Brazil.
The study on the animal was published in the journal Nature in July 2026. The species was named Tametara mirim.
“From the best preserved snake from the dinosaur era in our country, in a study also published in Nature Magazine in July 2026, the Tametara child snake.”
“Because of these and other finds, today the Prof. Pepe Paleontological Site is seen as a ‘window to the past’, revealing its paleontological richness to Brazil and the world, thanks to our excavations, our efforts and our dedication.”
