Maotherium asiaticus Ear Morphology (IMAGE) Carnegie Museum of Natural History Caption Maotherium is related to such modern mammals as Didelphis. But unlike marsupials and placentals, in which the middle ear is separated from the mandible, in Maotherium the middle ear is still attached to the mandible. Recent developmental biology studies have shown that the connection of middle ear to the mandible can “re-appear” as the genes control their development can change, and such genetic and developmental changes can impact evolution. Maotherium provides a strong case of how development has impacted fossil evolution in the deep history of Earth. Credit Zhe-Xi Luo/Carnegie Museum of Natural History Usage Restrictions Credit must accompany image. Full caption is optional. 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.