Paleontologists from the American Museum of Natural History and the Chinese Academy of Sciences announce the discovery
of Liaoconodon hui, a complete fossil mammal from the Mesozoic found in China that includes the long-sought transitional middle ear.
The specimen shows the bones associated with hearing in mammals -- the malleus, incus, and ectotympanic -- decoupled from the lower jaw, as had been predicted, but
were held in place by an ossified cartilage that rested in a groove on the lower jaw.
The new research, published in Nature this week, also suggests that the middle ear evolved at least twice in mammals, for monotremes and for the marsupial-placental group.
http://www.sciencedaily.com/releases/20 ... 132949.htm