A recent expedition in the Alto Mayo region of northwestern Peru has yielded an astonishing discovery: 27 previously unknown animal species, including a peculiar "blob-headed fish" and a semi-aquatic mouse. The survey was executed by Conservation International, an environmental non-profit organization, during a 38-day journey in 2022. The team explored the Alto Mayo landscape, which encompasses approximately 1.9 million acres of forests and agricultural lands, and is characterized by a rich tapestry of ecosystems.

Despite the area's high population density, there has been limited understanding of its biodiversity and ecosystem health, prompting the researchers to conduct this survey to fill the knowledge gaps. To their surprise, they identified an impressive array of new species: four mammals, eight fish, three amphibians, and ten butterfly species. A species is considered new to science when it has not undergone the formal scientific process of receiving a scientific name.

"The level of biodiversity we found in an area so heavily influenced by human activity was truly unexpected," remarked Trond Larsen, the expedition's leader and director of the Rapid Assessment Program at Conservation International. One of the most intriguing finds was an amphibious mouse with webbed toes, adapted for aquatic life. This mouse belongs to a group of semi-aquatic rodents that are "extremely rare," according to Larsen, who also noted that they are "incredibly elusive and our knowledge about these creatures is minimal." The specific mouse species was found in a small, swampy forest area currently under threat from agricultural activities, highlighting its urgent need for conservation efforts. The other novel mammalian discoveries included a spiny mouse, a short-tailed fruit bat, and a dwarf squirrel.

The "blob-headed" fish, named for its distinctive, enlarged head, was another first-time description. Fish experts involved in the survey had never encountered such a feature. Larsen described the fish's head, saying, "The blob-headed fish has an incredibly odd head that resembles a giant swollen nose. Scientists have never observed anything like it, and the function of this strange, blob-like structure remains a mystery." One hypothesis suggests that the blob might aid the fish in detecting food, though this remains speculative.

The survey cataloged a total of 2,000 species across the landscape, which stretches from the Andes to the Amazon and includes Indigenous territories, towns, and cities. Among these species, 49 are listed on the International Union for the Conservation of Nature's Red List, indicating they are at risk of extinction. The researchers hope that a deeper understanding of the region's biodiversity will facilitate the implementation of effective conservation strategies in the face of threats such as deforestation and agricultural expansion.

While these discoveries were "new to science," they were not entirely unknown to local communities. The expedition involved local indigenous researchers and continues to work in collaboration with indigenous communities on conservation efforts. Yulisa Tuwi, an Awajún woman who contributed to the survey's research on reptiles and amphibians, stated, "This Rapid Assessment empowers the Awajún community to safeguard our culture, natural resources, and territory, as we have a profound connection with nature.

Participating in this research has enabled me to gain a better understanding of how plants, animals, and ecosystems interact, which is integral to our Awajún worldview." She further expressed in a press release, "Our primary objective is to provide the scientific knowledge necessary to advance conservation in a manner that benefits both nature and people." Larsen emphasized the urgency, adding, "We are racing against time to meet global biodiversity conservation goals."