March 27, 2013
Two New Lemur Species Discovered, Already Endangered
Alan McStravick for redOrbit.com - Your Universe Online
A recent animated movie franchise introduced children around the world over to an island just off the coast of Africa and its immense biodiversity. Perhaps unknown to those children and even their parents is the fact this diversity continues to increase thanks to the dedication of scientists who continually seek out new species.
The mouse lemur, a saucer-eyed, teacup-sized primate is an example of diversity that can only be found in the wild on the island of Madagascar. The large African island has been recognized as one of the most important conservation hotspots on the planet. And lemurs are the last living survivors of an ancient family of primates with a common connection to the primate lineage that eventually evolved into humans. It is for this reason that lemurs are regarded as being especially important to understanding the origin and evolution of Homo sapiens.
Recently, scientists identified two new species of mouse lemur on the island. With this find, the number of recognized species of mouse lemur increases to 20. But discovering and discerning these new species was no easy task due to the fact that the animals live a reclusive, nocturnal existence. Added to this is the fact that they look very similar to their cousins on the island and the only certain way to determine their distinct differences required the scientists to utilize genetic sequencing.
These new mouse lemurs are diminutive in size, weighing between 2.5 and 3 ounces, and their coat is covered with a grey-brown fur. “You can´t really tell them apart just by looking at them through binoculars in the rainforest,” said senior author Peter Kappeler of the German Primate Center in Goettingen, Germany. Though back in Germany now, Kappeler earned his PhD at Duke University in 1992.
The first of the newly discovered species was named the Anosy mouse lemur, or Microcebus tanosi. While M. tanosi is a close neighbor of both the grey mouse lemur and grey-brown mouse lemur, the researchers say genetic data indicates that there is no interbreeding between the three species.
The second species was given the name Marohita mouse lemur, or Microcebus marohita. The name Marohita, meaning “many views” in the native tongue, refers to the forest where this new species was found. However, the scientists pointed out in their study that this species is under threat from ongoing habitat destruction.
While the world is only just now learning of these two new lemur species, it was back in 2003 and 2007, on an expedition into the eastern part of the country that the report´s co-author Rodin Rasoloarison of the University of Antananarivo in Madagascar captured the two primates. Rasoloarison weighed and measured them and took small skin samples that were later used for genetic analysis in the lab.
Anne Yoder and Dave Weisrock, both of Duke University at the time, were also co-authors of the study. They analyzed two mitochondrial and four nuclear DNA genes in the attempt to figure out just where these new animals fit into the lemur family tree. This genetic analysis was first published in 2010. However, it wasn´t until now that the two new species officially received their names and descriptions.
Earlier this week, redOrbit´s Brett Smith wrote on how a group of American and Canadian scientists had just completed mapping the entire genome of another species of lemur on the African island. The recognition of the scarcity of these tiny primates makes work on the island all the more pressing.
This most recent study, published in the March 26 online issue of the International Journal of Primatology was funded by a grant from the German Research Foundation.
NEW SPECIES ALREADY ENDANGERED
Rasoloarison returned to the forest where he discovered M. marohita last year. When Rasoloarison compared the area to how it appeared on his 2003 expedition, he was shocked to find much of the lemur´s forest home had been cleared. It was this mass deforestation that led the International Union for the Conservation of Nature (IUCN) to classify the new species as “endangered” even before it was formally named and described.
"This species is a prime example of the current state of many other lemur species," Kappeler said. The presence of mouse lemurs on Madagascar has spanned the last 7 to 10 million years. However, with human presence on the island over the previous 2,500 years, activities such as logging and slash and burn agriculture have decimated the forest regions that these tree-dwelling primates call home.
In fact, only 10 percent of Madagascar´s original forests remain today. According to the IUCN, this makes the lemur among the most endangered mammals in the world.
"Knowing exactly how many species we have is essential for determining which areas to target for conservation," Kappeler said.
According to experts, achieving an increased understanding of mouse lemur diversity could benefit humans as well. This is because the mouse lemur is a far closer genetic match to humans than either mice or rats which are the most common lab animals used for genetic research. In fact, at least one species of mouse lemur — the grey mouse lemur — develops a neurological disease that is, say scientists, strikingly similar to Alzheimer´s disease. For this reason, researchers claim the lemur could potentially be an important model in helping us to understand the aging brain.
"But before we can say whether a particular genetic variant in mouse lemurs is associated with Alzheimer's, we need to know whether that variant is specific to all mouse lemurs or just select species," said Duke´s Lemur Center Director Anne Yoder.
"Every new mouse lemur species that we sample in the wild will help researchers put the genetic diversity we see in grey mouse lemurs in a broader context," she said.