Matamata
   Chelus fimbriatus, by William H. Espenshade III, an article about these turtles. They occur in northern South America, including both the Orinoco River and Amazon River basins.
   http://www.tortoise.org/archives/matamata.html

Matamata Turtles
   Chelus fimbriatus biology and captive requirements, by David T. Kirkpatrick.
   http://www.unc.edu/~dtkirkpa/stuff/mata.html

Scientific Expeditions to Patagonia Organized by University of Connecticut
   Groundbreaking ecological research at Torres del Paine National Park, Magallanes, Chile. Details about past and future expeditions.
   http://www.canr.uconn.edu/paine/