Common Ancestor (image) American Museum of Natural History Caption This is an artist's rendering of the hypothetical placental ancestor, a small insect-eating animal. The research team reconstructed the anatomy of the animal by mapping traits onto the evolutionary tree most strongly supported by the combined phenomic and genomic data and comparing the features in placental mammals with those seen in their closest relatives. Credit Carl Buell Usage Restrictions Can be used with appropriate credit 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.