A new monkey is swinging through the Amazon rainforests—at least it's new to scientists. Unfortunately, the future of this mini monkey, weighing in at just 7.5 ounces (213 grams) and nine inches (23 centimeters) tall, is already threatened by human development.

The discovery of Mura's saddleback tamarin was announced today by the Wildlife Conservation Society (WCS) in New York City and published online in the International Journal of Primatology.

"We keep finding new species of plants, insects and butterflies. But it is more and more difficult to find newer species of mammals," says Avecita Chicchón, director of WCS's Latin American and Caribbean Program, unable to suppress her excitement about the new rabbit-size primate. "It is our relative, albeit a little more distant than the gorilla. Looking into its eyes is like looking in the mirror."

The new subspecies of saddleback tamarin is gray and brown in color, with a mottled back and long tail. It is named for the Mura Indians who populate the remote Purus and Madeira river basins where the monkey lives. At this point, scientists have no way of knowing just how many roam the region.

This portion of Brazil is also home to several development projects, including a section of major highway currently being paved through parts of the Amazon's approximately  2.7 million square miles (seven million square kilometers) of tropical rainforest. Construction has also begun on two hydroelectric dams, with a proposed gas pipeline likely close behind.

"These are a significant threat to wildlife that are not even documented," Chicchón says. She advocates the need for more thorough calculations of costs and benefits—for the environment, the people and the wildlife—before these kinds of projects are carried out.

Although the monkey's discovery likely won't stave off the development, Chicchón believes that it will "help us highlight the need to keep doing explorations and to document the diversity of life in the Amazon—the last wilderness on Earth."