Scientists discover new species of cloud-forest rodent
January 2007. A strikingly unusual animal was has been recognised from the cloud-forests of Peru. The large rodent is about the size of a squirrel and looks a bit like one although its closest relatives are spiny rats. The nocturnal, climbing rodent is beautiful yet strange looking, with long dense fur, a broad blocky head, and thickly furred tail. A blackish crest of fur on the crown, nape and shoulders add to its distinctive appearance.
The scientists actually found the rodent in 1999 while conducting field research in Peru’s Manu National Park and Biosphere Reserve Mountains in Southern Peru along the eastern slope of the Andes. The new rodent was discovered at an altitude of 6,200 feet. Little is known about its lifestyle because subsequent efforts to locate and observe the animal were fruitless.
Why does it take so long to accredit a new species?
- According to Bruce Patterson, of the Field Museum, Chicago:-'Throughout the 20th century, lag times (the time between the animal being found and the date it is accredited) increased exponentially, from about 2 years at the turn of the 20th century to 14 years and rising by 1990. There are many factors involved but greater rigor, more careful comparisons, and the search for phylogenetic relationships are all involved. In the case of the new Spiny Rat in Peru, we not only described the new critter (which we knew was new in the field) but also revised the diagnosis of the genus (which required study of its 5 closest relatives and then comparisons of the collective group to all other spiny rats). These comparative analyses shed a lot more light than a simple description (in this case telling us about the origins of soft, lax coats among spiny rats) but take a lot more time and effort.'
Extending from lowland tropical forests in the Amazon Basin to open grasslands above the Andean tree line, Manu is home to more species of mammals and birds than any equivalently sized area in the world. ‘Like other tropical mountain ranges, such as the Himalayas, Ruwenzoris, Virungas and Kinabalu, the Andes support a fantastic variety of habitats,’ said Bruce Patterson, MacArthur Curator of Mammals at The Field Museum. ‘These in turn support some of the richest faunas on the planet.’
I. barbarabrownae belongs to a family of rodents known as ‘spiny rats’ because most of the species in that family bristle with spines. Its discovery has necessitated a re-examination of this tropical American family, especially its closest relatives, the bush-tailed tree rats found in South America’s lowlands. As a result of the recent discovery, the authors have used The Field Museum’s Pritzker Lab for Molecular Systematics and Evolution to resolve the evolutionary relationships among all of these rodents.
‘The new species is not only a handsome novelty,’ Patterson said. ‘Preliminary DNA analyses suggest that its nearest relatives, all restricted to the lowlands, may have arisen from Andean ancestors. The newly discovered species casts a striking new light on the evolution of an entire group of arboreal rodents.’
Other discoveries made in Manu.
The work of the international field research team that found I. barbarabrownae stretched over three seasons (1999-2001) and resulted in the discovery of 11 additional species new to science in a single river valley: 1 opossum, 7 bats, and 3 rodents. In November 2006, a synopsis of the entire project was published in Fieldiana: Zoology, a scientific publication of The Field Museum. The article is called ‘Mammals and Birds of the Manu Biosphere Reserve, Peru.’ It lists 222 species of mammals, 94 of which are bats, and 1,005 species of birds, twice the number of bird species breeding in the United States and Canada combined.
To read more about the expedition and the other discoveries, click here.
‘Students from San Marcos University in Lima made up two-thirds of the team collecting mammals, birds, and their parasites,’ Patterson said. ‘Peruvian students have described most of the new species while pursuing graduate studies overseas. Manu trainees are now enrolled in universities in Illinois, Texas, Michigan, Mexico and the United Kingdom.’
The research was sponsored by the National Science Foundation, the Museo de Historia Natural at the Universidad Nacional Mayor de San Marcos in Lima, and The Field Museum.
‘The new species is not only a handsome novelty,’ Patterson said. ‘Preliminary DNA analyses suggest that its nearest relatives, all restricted to the lowlands, may have arisen from Andean ancestors. The newly discovered species casts a striking new light on the evolution of an entire group of arboreal rodents.’
Other discoveries made in Manu.
The work of the international field research team that found I. barbarabrownae stretched over three seasons (1999-2001) and resulted in the discovery of 11 additional species new to science in a single river valley: 1 opossum, 7 bats, and 3 rodents. In November 2006, a synopsis of the entire project was published in Fieldiana: Zoology, a scientific publication of The Field Museum. The article is called ‘Mammals and Birds of the Manu Biosphere Reserve, Peru.’ It lists 222 species of mammals, 94 of which are bats, and 1,005 species of birds, twice the number of bird species breeding in the United States and Canada combined.
To read more about the expedition and the other discoveries, click here.
‘Students from San Marcos University in Lima made up two-thirds of the team collecting mammals, birds, and their parasites,’ Patterson said. ‘Peruvian students have described most of the new species while pursuing graduate studies overseas. Manu trainees are now enrolled in universities in Illinois, Texas, Michigan, Mexico and the United Kingdom.’
The research was sponsored by the National Science Foundation, the Museo de Historia Natural at the Universidad Nacional Mayor de San Marcos in Lima, and The Field Museum.
This map shows where the new species of brush tailed rodent was discovered in Peru’s Manu National Park and Biosphere Reserve. It also shows where scientists have located each of the five other species of the genus Isothrix. The dark areas represent moist broadleaf forests; pale areas represent dry broadleaf forests; and stippled areas represent grasslands, savannas and shrublands.
