New Monkeys Hint at Amazon Biodiversity

Two new species of marmosets, squirrel-sized New World monkeys, have been identified in the heart of the Brazilian Amazon. The brightly colored animals came to scientific attention only because they were living as pets in small riverbank settlements--suggesting that the number of undiscovered species in the Amazon basin is even greater than scientists suspect.

Callithrix manicorensis and C. acariensis, described in the March Neotropical Primates, are both light-colored: one silvery with a yellow belly and black tail, and the other snow white and sporting a gray racing stripe and an orange-tipped black tail. Dutch primatologist Marc van Roosmalen of the National Institute for Amazon Research in Manaus noticed the monkeys while doing fieldwork in the Rio Madeira basin, a remote area in northwestern Brazil, for Washington, D.C.-based Conservation International.

The discovery proves that "we are still far from understanding the biodiversity of most tropical organisms," says primatologist John Fleagle of the State University of New York, Stony Brook. The fact that scientists had completely missed species of "brightly colored, diurnal mammals" suggests that "the unknown diversity in small, less visible taxa must be vastly greater."