Swimming mouse among 27 new species discovered in Peru

An amphibious mouse with webbed feet and a fish with a round head are among 27 new species discovered by scientists in Peru.

They were discovered during an expedition to Alto Mayo, which includes the Amazon rainforest, by scientists from the nonprofit Conservation International and members of local indigenous groups.

Up to 48 other new species may also have been discovered, although further study will be needed to determine whether they are new, according to Conservation International.

“Discovering so many new species of mammals and vertebrates is truly incredible, especially in such a human-influenced landscape,” said Trond Larsen, senior director of Conservation International.

Alto Mayo is a protected area in northern Peru with multiple ecosystems and indigenous territories.

Its population density is relatively high, putting pressure on environmentalism through deforestation and agricultural expansion, Conservation International said.

Yulisa Tuwi, an Awajún woman who contributed to the research, said the report “empowers the Awajún to protect our culture, our natural resources and our territory” because it gives them a better understanding of ecosystems.

“[The Awajún] have extensive traditional knowledge about the forests, animals and plants they live with,” Mr Larsen said.

The expedition also discovered a new species of dwarf squirrel, eight species of fish, three amphibians and ten species of butterflies.

This round-headed fish is a new discovery for science, but the indigenous Awajún people who participated in the expedition already knew of its existence.

Fish experts were particularly shocked by its enlarged head – something they had never seen before.

This dwarf squirrel measures just 14 cm (5.5 inches), half the length of an average gray squirrel in the UK, which ranges from 24 to 29 cm, according to the UK Squirrel Agreement.

“[It] fits so easily in the palm of your hand. Adorable and beautiful brown color, very fast,” Larsen said.

“He jumps quickly and hides in the trees.”

Scientists have discovered a new species of spiny mouse, named after the particularly stiff guard hairs found on their fur, which function similarly to a hedgehog's spines.

They also discovered a new “amphibious mouse”, with partially webbed feet and which feeds on aquatic insects.

It belongs to a group of semi-aquatic rodents considered one of the rarest in the world, with the few known species having only been spotted a few times by scientists.