NEW SPECIES OF MONKEY FOUND IN AMAZON RAIN FOREST.

Byline: Les Line The New York Times

A curious, squirrel-size marmoset from the Amazon rain forest is the sixth new monkey species to be discovered in Brazil since 1990, and a scientist predicts that several more primate species will be found there by the end of the century.

``This shows how little we know about biological diversity among even our closest relatives,'' said the scientist, Dr. Russell Mittermeier, a primatologist and president of Conservation International in Washington.

The newly discovered species, the Satere marmoset (Callithrix saterei), is named for a group of Indians indigenous to the central Amazon area between the Madeira and Tapajos rivers where the first animals were collected. Mittermeier said the species had a distinctive face and ears, unpigmented facial skin, mahogany-colored fur and fleshy appendages on the genitalia of both sexes whose purpose has biologists puzzled. ``There's no other marmoset like it,'' he said. The species is described in the current issue of the Brazilian scientific journal Goeldiana.

Marmosets are among the smallest primates and are found mainly in the Amazon region of South America, where they live in small groups. Marmosets run along horizontal branches, leaping from twig to twig, and mainly eat insects and soft fruit; their long tails are not adapted for grasping. Female marmosets mate with more than one male, and the young are raised cooperatively with the males carrying the offspring on their backs, transferring them to the mother at feeding time.

The golden lion tamarin with its flowing mane and long reddish fur is possibly the best known of the 18 species of marmoset and is one of the world's most critically endangered mammals. Conservation International, which works to preserve global biodiversity, estimates that only 500 to 600 golden lion tamarins survive in the wild in the Atlantic Forest near Rio de Janeiro because of habitat loss and decades of unregulated exports to zoos, pet dealers and laboratories.

In contrast, the Satere marmoset does not appear to be threatened, Mittermeier said. While researchers have not defined the species' range, he said that most Amazon marmosets are adaptable and tend to be found in greater numbers at the edge of clearings, in abandoned slash-and-burn plots and in second growth rather than in primary rain forest. It is apparently not hunted for food.

The marmoset's discovery raises the count of primate species in Brazil to 75 of some 250 species worldwide.