Expeditions to Amazonia reveal new species of toads, lizards, birds and plants

Understanding the evolutionary history of Neotropical biota and past relationships between Amazonian and Atlantic Rainforest are the goals of a team led by zoologist Miguel Trefaut Rodrigues.

By Karina Toledo  |  Agência FAPESP – The idea of spending a month surrounded by the sounds of a tropical forest, without internet access or any hope of a hot shower, sleeping in a hammock or tent and working from five in the morning until midnight, even on weekends, must appear stressful to many. However, for zoologist Miguel Trefaut Rodrigues, an expedition undertaken in such conditions is “the most relaxing experience in the world”.

Rodrigues, a professor in the University of São Paulo’s Bioscience Institute (IB-USP) in Brazil, has led two scientific expeditions to practically unexplored parts of the Amazon in the past several months. Their main aims were to garner more knowledge of the evolutionary patterns in the Neotropical biota and to explore past relationships between the Atlantic Rainforest and Amazon biomes through research on these animals and plants.

Each expedition lasted 30 days and involved at least ten researchers with different specialties, as well as a logistical support team. They were funded by FAPESP via projects for which the principal investigators are Rodrigues and his IB-USP colleague Cristina Miyaki. Both projects are being conducted under the aegis of FAPESP’s Research Program on Biodiversity Characterization, Conservation, Restoration & Sustainable Use (BIOTA-FAPESP).

“In the first expedition, we collected more than 700 specimens of 104 different species, including reptiles, amphibians, small mammals, birds and plants. The material is still being analyzed, but we believe it will be possible to describe several new species. In the second expedition, we collected more than 1,000 specimens of some 110 species, most of which were lizards,” Rodrigues told Agência FAPESP.

The first expedition, which took place in October-November 2017, focused on Pico da Neblina, the highest point in Brazil, located 2,995 m above sea level in a full protection nature conservation unit near the border with Venezuela.

Because part of Pico da Neblina National Park lies within the Yanomami Indigenous Territory, the researchers required permission from the National Foundation for Indigenous Peoples (FUNAI) and the Brazilian Army to carry out fieldwork there.

“It was a long negotiation,” Rodrigues said. “We almost gave up, but exploring the fauna in Brazil’s highest area had been our wish for many years.”

At last, it was agreed that the expedition would be led and logistically supported by the Brazilian Army, which keeps a battalion stationed to support the Yanomami in Maturacá, approximately 150 km from São Gabriel da Cachoeira in Amazonas State.

The research group flew to Manaus and from there traveled to Maturacá, where they stayed for two weeks collecting specimens. The second part of the campaign was conducted in the Pico da Neblina highlands.

“We know the landscapes found at altitudes above 1,700 m have nothing to do with today’s Amazonia. They consist of open types of vegetation, such as high-altitude meadows and grasslands, with a much cooler climate than the tropical forest, possibly similar to the climate of South America during the colder periods of the Quaternary [approximately 2.6 million to 10,000 years ago],” Rodrigues said.

Among the 700 specimens collected, the group identified 12 new toad and lizard species, as well as a small owl never described in the scientific literature.

“As for plants, so far, we’ve identified one new species, but I expect we’ll discover about ten more,” Rodrigues said. “They’re complex groups and have to be analyzed by experts. The small mammals are also still being analyzed, and very possibly we’ll have some good surprises.”

The material collected, he added, will not be used only to describe new species. It will also provide new knowledge of the evolutionary and phylogeographic history of South American flora and fauna.

“Several groups of animals are being studied in terms of genetics, morphology and physiology,” he said. “Some of these studies will help us appraise the risk of extinction of these species if temperatures in the area rise in the years ahead.”

The researchers have already been able to note, for example, that the species present on Pico da Neblina are entirely unrelated to the biota found in other parts of the Amazon region. To Rodrigues, this shows the tropical forest was not there when the Neblina Massif was formed. 

“That’s important, as it suggests a possible link between the biota on Pico da Neblina and the biota found in the Andes, Atlantic Rainforest and other biomes. We already have evidence for this. One of the lizard species we found, the green anole Anolis neblininus, is part of an evolutionary radiation that encompasses species endemic to the Andes and montane areas of Atlantic Rainforest in the Southeast of Brazil,” Rodrigues said. 

River barrier

The second expedition took place in April-May 2018 and was not supported by the Brazilian Army. “We had to hire a boat, as river travel was the only way to move through the forest,” Rodrigues recalled. “We spent a month sleeping in hammocks on the boat, where we also took all our meals and set up our lab. At each stop along the river, we had to engage a local guide. The [Rio] Negro is full of boulders, and accidents happen very easily.”

The group traveled by boat from Manaus to approximately 80 km upstream of Santa Isabel do Rio Negro, via the region where the Branco meets the muddy waters of the Negro. Specimens were collected on both banks at different points along the way.

“Because of its low density and high acidity, the Negro is considered faunistically poor,” Rodrigues said. “We wanted to study the influence of the Branco’s waters on species diversity and abundance. Another goal was to understand the Negro’s role as a geographic barrier to species differentiation. That’s why we collected specimens on both banks.”

Traps made from buckets and plastic tarpaulins were installed in the forest to capture small animals, especially reptiles and amphibians. The research line led by Rodrigues aims to understand the evolution of snakes, lizards, toads and frogs in South America.

“These animals are highly interesting from an ecosystems standpoint, as they form the base of the food chain,” he said. “In this second expedition, we obtained a spectacular collection with more than 1,000 specimens.”

They needed a large number of specimens to meet one of the goals of the second expedition, which was to explore the mechanisms behind the origin of a complex of parthenogenetic lizard species – species comprising only females that reproduce asexually – belonging to the genus Loxopholis. 

This project, conducted by two postdoctoral researchers supervised by Rodrigues – Sérgio Marques de Souza and Tuliana Oliveira Brunes – also aims to understand why this part of the Amazon region is home to so many parthenogenetic lizards.

“We collected lizards of the genus Loxopholis at many different points. In some of these populations, we managed to find males. There are bisexual populations and others comprising only females with diploid and triploid karyotypes [with two or three sets of chromosomes, whereas human gametes have only one, for example].”

They also collected tree-dwelling lizards of the genus Anolis with the aim of investigating the evolution of these species in South America. This is the purpose of a postdoctoral research project conducted by Ivan Prates, currently a fellow at the Smithsonian Institution in the United States.

During the expedition, the group found parthenogenetic lizard species belonging to the genus Gymnophthalmus at three different sites along the Negro.

“Curiously, we found these animals in narrower parts of the river, on sand dunes that bear witness to a time when the Negro had a much drier climate than it has now,” Rodrigues said. “We plan to compare the specimens collected on each bank to see whether they belong to one and the same parthenogenetic species. They could be different clones. If so, we’ll try to find out when they separated. This will contribute to an understanding of the history of the Negro.”

Despite the huge amount of material to be analyzed, the researchers are already planning their next expedition to the Amazon, for which they expect again to receive logistical support from the Brazilian Army. This time, the goal is to sample the fauna that inhabit the highlands of Pacaás National Park in Rondônia, in collaboration with a team of parasitologists led by Erney Plessman de Camargo, a professor in the University of São Paulo’s Biomedical Science Institute (ICB-USP).