Image: MARK WIDHALM Field Museum

These days, discovering a new species usually means adding a new plant, microbe or invertebrate to the roster of living things that inhabit our planet. Identifying new species of large animals or creatures that belong to well-studied groups is extremely rare. But according to two new analyses researchers appear to have done just that. One report, published in the November issue of the journal Molecular Ecology, reveals that a population of right whales living in the North Pacific Ocean in fact represents a separate species. The other report, which will appear in the December International Journal of Primatology, describes three new species of mouse lemurs--the tiniest living primates.

When Wildlife Conservation Society researcher Howard Rosenbaum and his colleagues examined DNA from North Pacific right whales, they found them to be genetically distinct from the other two known species, the northern right whale of the North Atlantic Ocean and the southern right whale. Biologists know very little about these giants--which reach some 45 feet long and weigh around 50 tons--in part because there aren't very many of them (illegal hunting has taken its toll on their population size). "What is known," says Rosenbaum, "is that this animal numbers perhaps a few hundred individuals throughout their entire range in the North Pacific and should therefore be a top conservation priority."

In the second study Steven Goodman of the Field Museum in Chicago and his colleagues compared the physical characteristics of mouse lemurs from 12 locations on Madagascar, where they are endemic. Considerable differences in the forms of their teeth, skulls and body sizes led the researchers to add three new species (see skulls above) of the diminutive primates to the four that were already known. "It was already clear from museum specimens that there was a tremendous amount of variation among mouse lemurs," Goodman says. "But previous assessments were based on too few specimens from widely scattered localities, many very discolored and as much as 150 years old. The data were not adequate to assess variation within a population." The team named the new species Microcebus berthae, Microcebus sambiranensis and Microcebus tavaratra.

Like most of Madagascar's wildlife, lemurs are found nowhere else on Earth. And like most of Madagascar's wildlife, they are in grave danger of extinction. "Anything living in the forest in Madagascar is threatened due to the rapid loss of habitat," Goodman remarks. "At this point it's not a race to save things: it's a race to know what's there." Sadly, the new mouse lemurs may well disappear almost as suddenly as they were discovered.