The swimming mouse is among 27 new species discovered in Peru

An amphibian mouse with webbed feet and a drop-headed fish are among 27 new species discovered by scientists in Peru.

They were found by scientists from the non-profit organization Conservation International and members of local indigenous groups during an expedition to Alta Mayo, which includes the Amazon rainforest.

Up to 48 other new species may also have been found, but more research will be needed to determine whether they are new, Conservation International said.

“The discovery of so many new species of mammals and vertebrates is truly incredible, especially in such a human-impacted landscape,” said Trond Larsen, Senior Director of Conservation International.

Alta Mayo is a protected area in northern Peru with many ecosystems and indigenous territories.

It has a relatively high population density, which puts pressure on the environment through deforestation and agricultural expansion, notes Conservation International.

Yulisa Toovey, an Awajun woman who helped with the study, said the report “enables the Awajun to protect our culture, 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 side by side with,” Mr Larsen said.

The expedition also discovered a new species of pygmy squirrel, eight species of fish, three amphibians and 10 species of butterflies.

This fish with “droplet heads” was a new discovery for science, but the native people of Awajun, who helped in the expedition, already knew about its existence.

The fish scientists were particularly shocked by its enlarged head – something they had never seen before.

This pygmy squirrel measures just 14 cm (5.5 in), half the length of the common 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. Lovely and beautiful chestnut brown, very fast,” Larsen said.

“It jumps quickly and hides in the trees.”

Scientists have discovered a new species of spiny mice – named after the particularly tough protective hairs on their fur that function much like the spines of a hedgehog.

They also found a new “amphibian mouse” that has partially webbed feet and eats aquatic insects.

It belongs to a group of semi-aquatic rodents that are considered among the rarest in the world, with the few known species that exist having only been seen a few times by scientists.