Mammalian development does not recapitulate suspected key transformations in the evolutionary detachment of the mammalian middle ear.

ABSTRACT: The ectotympanic, malleus and incus of the developing mammalian middle ear (ME) are initially attached to the dentary via Meckel's cartilage, betraying their origins from the primary jaw joint of land vertebrates. This recapitulation has prompted mostly unquantified suggestions that several suspected--but similarly unquantified--key evolutionary transformations leading to the mammalian ME are recapitulated in development, through negative allometry and posterior/medial displacement of ME bones relative to the jaw joint. Here we show, using µCT reconstructions, that neither allometric nor topological change is quantifiable in the pre-detachment ME development of six marsupials and two monotremes. Also, differential ME positioning in the two monotreme species is not recapitulated. This chall

SUBMITTER: Ramirez-Chaves HE 

PROVIDER: S-EPMC4721106 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature