Natalie Angier writes about the middle ear of a Mesozoic mammal: "In Mammals, a Complex Journey to the Middle Ear".
The finding also dovetails with recent work in molecular genetics and developmental biology. Among modern mammals, the middle ear of a fetus is one of the last structures to mature and migrate to its proper position, and even after birth the little bones may retain a few lingering filaments of so-called Meckel’s cartilage, which connects the ear to the jaw in the early embryo. Dr. Luo and his colleagues suggest that a mutation to a developmental timing gene responsible for this late-stage disengagement might have essentially locked Maotherium’s ears into a permanent embryonic state, just as can happen with rare human craniofacial disorders like Treacher Collins syndrome. “Fossil hunters, developmental biologists, medical geneticists, we’re all meeting eye-to-eye,” Dr. Luo said.
