Swimming mouse is one of 27 new species discovered in Peru

An amphibious rat with webbed feet and a blob-headed fish are among the 27 new species that scientists have discovered in Peru.

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

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

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

Alto Mayo is a protected area in northern Peru containing several ecosystems and indigenous areas.

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

Yulisa Tuwi, an Awajun woman who assisted with the research, said the report “allows the Awajun to protect our culture, natural resources and our territory”, because it gives them a better understanding of the ecosystem.

“(The Awajun) have extensive traditional knowledge about the forests, animals and plants with which they live,” Mr Larson said.

The expedition also found a new species of dwarf squirrel, eight types of fish, three amphibians and 10 types of butterfly.

This “blob-headed” fish is a new discovery to science, but the indigenous Awajun people who helped with the expedition already knew of its existence.

Fish scientists were particularly surprised by its enlarged head – something they had never seen before.

This dwarf squirrel measures just 14 cm (5.5 in) tall, which is 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 very easily in the palm of your hand. Adorable and beautiful chestnut-brown color, very sharp,” Larson said.

“It jumps fast and hides in the trees.”

Scientists discovered a new species of spiny mouse – named after the particularly tough guard hairs found on their coats, which function similarly to a hedgehog’s spines.

They also found a new “amphibious rat”, which has partially webbed feet and eats aquatic insects.

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