JEHOLBAATAR KIELANAE

Dec. 2, 2019

Researchers have unearthed well-preserved middle ear bones from a new species of an extinct rodent that lived 145-66 million years ago in what is now northeastern China.

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The study, published in the journal Nature, looked at fossils of the extinct rodent-like mammal — Jeholbaatar kielanae — at Jehol Biota of China, and noted that these animals had a middle ear that is distinct from those of its relatives.
The fossil clues provide solid evidence of the morphology and formation of the inner ear bones, which are fully detached from the lower jaw. The new fossil reveals a transitional stage in the evolution of the surangular — a “reptilian” jawbone.
In these extinct mammals, the evolution of the middle ear may have probably been triggered by functional constraints on the bones and muscles involved in feeding.
This advance may lead to better understanding of the evolution of hearing.

Source : The Hindu