Andes field trip reveals new species of climbing rodent

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Zoologists have discovered a new species of squirrel-like mammal, which they have described as a strikingly unusual creature, in the high mountains of Peru.

The nocturnal animal looks similar to a squirrel, and is about the same size, but DNA tests have shown that it is more closely related to a family of South American spiny rats, whose fur bristles with spines.

The new species is a climbing rodent with strange-looking, long, dense fur, a broad head and thickly furred tail tipped with white. It also has a distinctive blackish crest of fur on its crown, nape and shoulders.

Scientists discovered the rodent during a field survey in 1999 of Peru's Manu National Park and Biosphere Reserve Mountains on the lush eastern slopes of the Andes in southern Peru, which is one of the richest regions in the world for wildlife.

Its formal scientific description and official naming has only now been made public with the publication today of a description of the Manu reserve findings in the journal Mastozoologia Neotropical. The same field trip, which extended from 1999 to 2001, uncovered 11 additional species new to science, namely one opossum, seven bats and three other rodents.

"Like other tropical mountain ranges, such as the Himalayas, the Andes support a fantastic variety of habitats. These in turn support some of the richest faunas on the planet," said Bruce Patterson, the curator of mammals at the Field Museum in Chicago, who led the research team.

"The new species is not only a handsome novelty. Preliminary DNA analyses suggest that its nearest relatives, all restricted to the lowlands, may have arisen from Andean ancestors," Dr Patterson said.

"The newly discovered species casts a striking new light on the evolution of an entire group of arboreal rodents," he added.

Little is known about the species - which has been named Isothrix barbarabrownae after a Field Museum scientist called Barbara Brown - except that it lives in the cloud forests at an altitude of 6,200 feet and probably feeds on seeds, nuts, berries and small insects.

Subsequent attempts to find further specimens of the rodent have failed. The species is known to have five other close relatives belonging to the same genus living in South America.

The Manu reserve extends from the lowland forests of the Amazon basin to open grasslands above the Andean tree line.

It is home to more species of mammals and birds than any other area of the world of comparable size. In total, the team recorded 222 species of mammals, 94 of which were bats, and 1,003 species of birds, twice the number of breeding bird species in North America, during the three-year field trip.

Sam Turvey, a research fellow at the Zoological Society of London, said that this region of South America is renown for being one of the richest regions in the world for biodiversity.

"It covers an area from low to very high altitude, which supports many different kinds of ecosystems. It's very much a centre for biodiversity," Dr Turvey said. "People think it's very unusual to describe a new species of mammal such as this one but in fact several new mammals and birds are routinely reported each year. There's still a lot of new species of relatively large animals in the world left to be described, certainly more than we think."