Notebook
Monday, May 23, 2005
Monkey Species Discovered
Two teams of scientists working hundreds of miles apart in Tanzania have independently discovered a new species of monkey -- the first new African monkey to be discovered in 21 years.
Dubbed the highland mangabey, Lophocebus kipunji is about three feet long from head to rump with a three-foot-long tail; weighs about 30 pounds; has long, mostly brown fur; sports a lighter brown, spiky, punklike hairdo; and communicates with a distinctive call that is more of a "honk-bark" than the standard-issue mangabey's "whoop-gobble," the teams report in the May 20 issue of Science magazine.
Mangabeys are a kind of monkey found only in equatorial Africa. Their closest relatives are baboons and mandrills.
The hunt began in January 2003, when researchers with the Wildlife Conservation Society (WCS) heard rumors of a shy and unusual monkey living in Tanzania's southern highlands. No one knew if the stories were true, because local people have a lively oral tradition based in part on mythical animals. But the WCS team spotted one in December of that year near Mount Rungwe.
Unaware of that, a team from the University of Georgia and Conservation International made a similar find the following July in the Udzungwa Mountains to the east.
Only last October, after they had been studying their respective populations for months, did the two groups find out about each other.
The two populations probably have no more than 500 individuals each. Those small numbers, along with heavy pressure from logging, poaching and other environmental insults, suggest to the researchers that the species deserves to be listed as critically endangered.
-- Rick Weiss
East Antarctic Ice Sheet Growth
Scientists have documented that global warming is causing ice sheets and glaciers across the globe to shrink, which in turn is pushing sea levels higher. Now a researcher at the University of Missouri at Columbia has discovered a rare piece of good news: The East Antarctic ice sheet's interior is actually growing.
Curt Davis and his team observed 7.1 million square kilometers of the East Antarctic ice sheet from 1992 to 2003 and determined with the aid of satellites that the ice sheet is gaining about 45 billion metric tons of mass a year. That could slow sea level rise -- about 1.8 millimeters a year -- by 0.12 millimeters annually.
Davis, whose findings appear online in the May 19 issue of Science Express, said this most likely makes the ice sheet the only large terrestrial ice body in the world to be gaining mass.
"Many recent studies have focused on coastal ice sheet losses and their contributions to sea level rise," Davis said in an interview Friday. "We think that the East Antarctic ice sheet is probably gaining mass at a rate comparable to the amount of mass being lost by the Greenland ice sheet."
Increased precipitation, especially snowfall, accounts for the sheet's growth, Davis said. Other scientists have predicted that global warming would have that effect in some regions, but Davis cautioned that it is too early to tell whether global warming is causing the growth of East Antarctica's ice.
-- Juliet Eilperin
How a Stegosaur Used Its Plates
Everybody knows that stegosaurs were the pea-headed dinosaurs with the double row of bony plates growing like banana leaves down their backs. But what, exactly, were the plates for?
To find out, a team led by researchers at the University of California at Berkeley cut up some of the plates, called scutes, and compared them with similar bones on related species.
The team concluded that stegosaurs used the scutes to identify other stegosaurs, probably a wise strategy for a not-particularly-bright vegetarian sharing its world 175 million years ago with ferocious predators.
"There were four possibilities for the scutes," said team member Russell Main, a Harvard biologist. "They could be for defense, display [to attract mates], thermoregulation or species identification."
In the spring issue of the journal Paleobiology, the team concludes that the scutes were too lightweight for defense.
Display was also ruled out, because male and female stegosaurs "look the same."
Thermoregulation -- controlling body temperature -- seemed a plausible explanation, because scute surfaces were threaded with blood vessels that could have cooled the blood during warm weather and warmed it during cool weather. But many stegosaur ancestors had scutes that lay flat or rose only slightly, not a good arrangement for heat exchange.
The team concluded that the vessels probably carried blood to facilitate rapid scute growth, like the vessels in the antlers of elk or moose. Although the scutes "may have acted passively" as thermoregulators, Main added, their most likely purpose was species recognition.
-- Guy Gugliotta