More than a quarter of the 166,000 species on the International Union for the Conservation of Nature’s Red List are threatened with extinction. That includes 41% of known amphibians, 26% of freshwater fish and 12% of birds. What’s more, continued global warming is only likely to drive those percentages higher. Often lost, however, in the justifiable concern for known species—especially iconic ones such as jaguars and giant tortoises—is the all-too-real possibility that many plants, animals and other organisms could vanish before scientists even are aware they exist.

In South America, these newly described, possibly already endangered species range from frogs high in Andean cloud forests to creatures at the bottom of the region’s deepest ocean trench. Finding and studying those species, scientists say, not only marks a first step toward protecting them, but can also help illuminate how our planet has evolved, how species might adapt and what future awaits all species on a warming Earth.

New to science, but often not to Indigenous people

When scientists spotted an unassuming brown salamander in the mountains of north-central Peru, they were excited—it was a species never before described in the scientific literature. But to Yulisa Tiwi Wajai, an Awajún teacher who worked as a field assistant to researchers recording reptiles and amphibians, the small creature was an old friend.

“We found it both in my community and in the white sand forest. It’s always been there. We Awajún, when we saw a lot of them, we’d say, ‘This is a place where we can plant sachapapa [Dioscorea spp., a potato-like wild tuber] or peanuts,” she adds. “That helped guide us, and having them there is good.”

She had a similar reaction when her team found a frog never described in the scientific literature. It was long known to Awajún hunters, who use a secretion from the frog’s skin on the tips of their arrows to paralyze or kill their prey.

Like other Indigenous peoples, the Awajún have a close relationship with the forest, “because ancestrally, our parents and grandparents lived off the land in this territory,” Tiwi Wajai says. Finding so many species identified as new to Western science “was a little surprising, because we’ve always had them there. We even ate them.” The combination of Western and Indigenous knowledge, she says, provides an even deeper understanding of the Awajún territory.

Scientists came across the salamander and frog during a rapid assessment led by the nonprofit group Conservation International (CI). The assessment, conducted June 6 to July 14, 2022, targeted an area of Peru’s north-central San Martín region that scientists refer to as Alto Mayo. Located on the eastern flank of the Andes, where montane and Amazonian ecosystems merge in a highly biodiverse transition zone, Alto Mayo covers some 780,700 hectares (3,014 square miles), sitting between 570 meters and 2,230 meters (1,870 feet and 7,316 feet) above sea level.

Ecosystems there include flooded forests, palm swamps, cloud forest and white sand forest. Some of the land studied was inside two protected areas—the Alto Mayo Protection Forest and the Cordillera Escalera Regional Conservation Area. Alto Mayo is home to 16 Awajún Indigenous communities, and an influx of settlers in recent years has led to deforestation aimed at accommodating agriculture, especially commodity crops such as coffee and cacao. The rapid assessment was intended mainly to fill a biodiversity “data gap” concerning the more settled land between the two protected areas. Investigators hope to use the information to guide the planning and creation of a conservation corridor linking the protected lands.

So far, biodiversity remains amid ongoing deforestation

Despite forest fragmentation and the study area’s proximity to villages and towns, the field teams recorded more than 2,000 species, including nearly 1,000 vascular plants, along with 151 mammals, 536 birds, 218 diurnal butterflies, 68 fish, 27 amphibians and 18 reptiles. Of the total, 27 species had never been documented in scientific literature, including a squirrel belonging to a previously undescribed genus, an aquatic mouse and a spiny mouse, several frogs, eight fishes, 10 butterflies, two dung beetles and a salamander.

Information from the rapid assessment will help conservationists, government officials and the communities, which are part of the Regional Awajún Federation of the Alto Mayo (Feriaam), to jointly plan land use, including environmentally low-impact economic activities such as ecotourism. These stakeholders will also discuss ways to guard against further forest fragmentation and protect eco-corridors that allow the movement of species between conservation areas, says Wily Palomino, CI’s program manager for the southern Peruvian Amazon, who participated in the rapid assessment.

Both Palomino and Tiwi Wajai stress the importance of the collaborative study, which included 13 researchers from outside the Indigenous communities, seven Awajún professionals and a dozen local Awajún guides. Although the Awajún team members did not necessarily know the scientific names of animals they recorded, they often were familiar with their behaviors and habitat preferences, even if they had not been described in scientific literature. Tiwi Wajai knew about the poisonous frog, for example, but did not know it might be critically endangered.

Meanwhile, the Awajún team members’ knowledge helps identify species that are indicators of ecosystem health, Palomino says.

“It would be good for the world to understand that the knowledge of the Awajún is very important in this type of research,” Tiwi Wajai says, “and not just focus on the behavior of plant or animal species, but also understand the people—what we’re like, our customs and our relationship with our territory, the forest and the animals.”

Once considered barren, trench found to be a trove

Marine biologist Johanna Weston has explored some of the deepest places in the world’s oceans and described at least five species that were new to the scientific literature. But one of her favorite spots is not far off the coast of Chile, in the Atacama Trench—a dark, frigid environment that is home to a surprising amount of life, and which could hold clues to how ocean environments will change as the planet warms.

“I really like these really deep ecosystems in general. I’ve worked in a number of different trenches, but I find the Atacama Trench to be a really interesting one,” says Weston, who began studying the hadal zone—the deepest parts of the ocean—in 2017.

One of those deep-sea zones is the Peru-Chile trench, located just off the coast of those two countries in the subduction zone where the Nazca Plate is sliding under the South American Plate. The Nazca Ridge off southern Peru splits the longer trench into two sections. The northern portion is the Milne-Edwards Trench, and the southern part is the Atacama Trench, where the deepest point is located—an area known as Richard’s Deep.

The combination of tectonic action, runoff from nutrient-laden rivers that begin high in the Andes Mountains, water depth—around 8,000 meters (26,246 feet) at the deepest point—and its isolation makes the Atacama Trench special, researchers say. Weston calls it essentially an island on the ocean floor. Oceanographer Carolina González of the Millennium Institute of Oceanography at the Universidad de Concepción in Chile says some water in the trench has been there 1,000 years or more, giving scientists a long look into the evolutionary past.

“Until 1948, it was thought that life couldn’t live deeper than 6,000 meters [below sea level],” Weston says. “And then an expedition to the Peru-Chile trench in 1948 … brought animals up, and they’re like, ‘Oh, life can live this deep.’ And life lives all the way to the deepest parts of the ocean.”

Although scientific expeditions using human-operated submersibles and remotely operated vehicles get the most popular headlines, the researchers’ workhorse is the “lander,” a tripod-like structure outfitted with cameras, instruments and baited traps, and designed to resist the enormous water pressure on the ocean floor. One of these traps’ most common catches are amphipods, a type of crustacean that has evolved to live in a variety of ecosystems, from beaches to trench bottoms.

Weston has authored papers describing five hadal species new to science and coauthored another. Her most recent discovery, published in December in the journal Systematics and Biodiversity, involves an amphipod identified not only as a new species but as a member of a previously unknown genus. Unlike most deep-sea amphipods, which are scavengers, Weston recognized the new one, dubbed Dulcibella camanchaca in a nod to the novel Don Quixote, as a predator.

González—coauthor of that paper and lead author of a new one about deep-sea amphipod evolution, published in January in the journal Ecology and Evolution—found Dulcibella camanchaca in a trap during a research trip in 2023 and sent a photo to Weston, who could tell at a glance that it was new.

Of all the unusual creatures in the hadal zone, amphipods are Weston’s favorites. “Not everyone finds them beautiful,” she says. But while doing her doctoral research at Newcastle University in the United Kingdom, she adds, “I had massive access to amphipods, and when you have that many sets of specimens, you can ask a lot of questions, and I fell in love with just really looking at them.”

Though remote, trench life faces human-posed risks

Isolated as they might seem, sea-floor trenches are not immune to human impacts. Both Weston and González worry about the effects of deep-sea mining, which will stir up sediment and disturb and destroy ecosystems about which scientists still know virtually nothing. While the Atacama Trench does not appear to have attractive mineral deposits, González says, it cannot be assumed to be isolated from undersea disturbances and human-caused pollution. The latter concern was underscored in 2019, when two Millennium Institute scientists making the first-ever descent in a submersible vessel found a plastic bag on the trench floor.

The bag served as a reminder that deep-water ecosystems are connected to the surface, says González, who studies the water column. Often in the course of her research, she takes water samples to find specimens and environmental-DNA traces of other creatures that have passed through the water at that depth. She then compares her samples against a global database.

“More than 50% of the organisms that live in deep trenches can’t be identified,” González says. “You can’t get to the species level in the database. That tells us that there is a great biodiversity that is unknown to us. So we have two challenges: there are many new species, but we can also see that we know very little about what’s down there.”

Molecular analyses of deep-sea organisms are also intriguing, González says, and could yield substances useful for developing pharmaceuticals or other products. In one practical example, an enzyme isolated from a microbe found around deep-sea hydrothermal vents as well as in freshwater hot springs contributed to development of the PCR test used to diagnose Covid-19.

For researchers, new discoveries often raise more questions than they answer. González was intrigued by an amphipod that had eyes, even though it lived in the dark. Analysis of proteins related to the eye suggested that it might detect infrared light. She calls such revelations “fascinating,” adding: “It makes you think about how little we know about the largest part of the planet.”