Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont

@article{Meng2011TransitionalMM,
  title={Transitional mammalian middle ear from a new Cretaceous Jehol eutriconodont},
  author={Jin Meng and Yuanqing Wang and Chuankui Li},
  journal={Nature},
  year={2011},
  volume={472},
  pages={181-185}
}
The transference of post-dentary jaw elements to the cranium of mammals as auditory ossicles is one of the central topics in evolutionary biology of vertebrates. Homologies of these bones among jawed vertebrates have long been demonstrated by developmental studies; but fossils illuminating this critical transference are sparse and often ambiguous. Here we report the first unambiguous ectotympanic (angular), malleus (articular and prearticular) and incus (quadrate) of an Early Cretaceous… 
Exploring ancestral phenotypes and evolutionary development of the mammalian middle ear based on Early Cretaceous Jehol mammals
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A monotreme-like auditory apparatus in a Middle Jurassic haramiyidan.
TLDR
It is proposed that the overlapping incudomallear articulation found in this and other Mesozoic fossils, in extant monotremes and in early ontogeny in extant marsupials and placentals is a morphology that evolved in several groups of mammals in the transition from the dual to the single function for the ossicles.
The Evolution and Development of Middle Ears in Land Vertebrates
New fossil evidence and supporting data from embryological studies have helped to consolidate interpretations of the structures that assemble the middle ear apparatus of different lineages of land
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