<i>Cryptonanus chacoensis</i> (IMAGE) Field Museum Caption This is Cryptonanus chacoensis, a South American oppossum whose species was represented in this study. Credit (c) Noé de la Sancha, The Field Museum. Usage Restrictions Please include credit line License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.