They were described by Marc van Roosmalen, a primatologist at Brazil's National Institute for Amazon Research (INPA), his son, Tomas van Roosmalen, and Russell Mittermeier, president of Conservation International and chair of the World Conservation Union (IUCN) Species Survival Commission's Primate Specialist Group.
"Even though our closest living relatives, the primates, have been very well-studied for the past four decades, we are once again surprised by the discovery of even more species," said Mittermeier. "It proves how much we still need to learn about biological diversity, especially in the tropical rainforests."
One of the species, Callicebus bernhardi, or Prince Bernhard's titi monkey, is remarkable for its dark orange sideburns, chest and the inner sides of its limbs, its reddish-brown back, and a white-tipped black tail. It lives between the east bank of the Rio Madeira and the lower reaches of its tributary, the Rio Aripuaña, south of the Amazon River.
Callicebus bernhardi is named for His Royal Highness Prince Bernhard of the Netherlands, a noted naturalist who created the Order of the Golden Ark to honor conservationists internationally. This prestigious award was bestowed upon co-authors Marc Van Roosmalen and Russell Mittermeier in recent years. Van Roosmalen will present the discovery to the Prince at Soestdijk Palace in Holland on June 25, four days before the Prince's 91st birthday.
Prince Bernhard will also receive a special portrait of his monkey by Stephen Nash, CI's technical illustrator, who has made major contributions to primate conservation worldwide through his posters and educational materials. The second new species, Callicebus stephennashi, is named after Nash, who works for Conservation International and is based at the Department of Anatomical Sciences at the State University of New York at Stony Brook.
Callicebus stephennashi, or Stephen Nash's titi monkey, is silver in color, with a black forehead and red sideburns, chest and inner sides of limbs. Since fishermen brought it to Van Roosmalen's Breeding Center for Endangered Wildlife in Manaus, it is uncertain where it lives. Van Roosmalen believes it came from the eastern bank of the Rio Purús in Central Amazonia.
"I am currently using my new discoveries to convince the Brazilian government to create nature reserves in the areas where I have found these species and where others, yet unknown to science, are likely to live," says Marc van Roosmalen. "The Amazon is extremely rich in biodiversity, and these newly-discovered creatures should be regarded as flagship species."
Scientists have described 24 monkeys new to science since 1990, according to Anthony Rylands, senior director at the Center for Applied Biodiversity Science at Conservation International, 13 of which are from Brazil. Including these two new monkeys, Brazil now has 95 species of primates, far more than any other country, and 134 species and subspecies, close to one-quarter of the global total. Van Roosmalen and Mittermeier have previously described four other new monkey species.
Titi monkeys are about the size of a small cat. They live in the dense understory of the South American tropical forests in small family groups of a mated pair and their offspring. Twenty-eight species, each with unique and colorful fur patterns, are now known to occur over a large part of the Amazon basin and the Atlantic forest of eastern Brazil.
Conservation International (CI) applies innovations in science, economics, policy and community participation to protect the Earth's richest regions of plant and animal diversity in the hotspots, major tropical wilderness areas and key marine ecosystems. With headquarters in Washington, D.C., CI works in more than 30 countries on four continents. For more information about CI's programs, visit www.conservation.org.