Chinanews.com, Beijing, December 7th (Reporter Sun Zifa) Springer Nature's academic journal "Nature-Communications" recently published an evolutionary research paper. The researchers described the use of the shape of the inner ear of ruminants to test the shape of herbivores spanning 3,500 years. Thousands of years of evolutionary history.

The findings link changes in inner ear shape to deer and cattle diversification, climate, and dispersal to new habitats.

The location and reconstruction of the deer inner ear (Source: Laura Dziomber).

Photo courtesy of Springer Nature

　　According to the paper, the inner ear senses motion and direction, and its shape and size are used to infer the agility of extinct animals.

The bone of the inner ear (the bony labyrinth) is unusually dense and well preserved in the fossil record, meaning it can be used to study aspects of mammalian evolution over millions of years.

The evolution of the ruminant inner ear is marked by 35 million years of environmental and geological influences (Credit: Laura Dziomber).

Photo courtesy of Springer Nature

　　The paper's corresponding author, Bastien Mennecart of the Museum of Natural History in Basel, Switzerland, and collaborators studied 306 living and fossilized inner ear bones of ruminants, including giraffes, deer, cattle, sheep and goats , spanning their 35 million-year evolutionary history.

Using 3D X-ray data to measure these inner ear bone shapes, they found small, nonfunctional inner ear shape variation consistent with the evolution of new species in this taxon.

For example, accelerated changes in the inner ear of deer coincide with the evolution of 19 new deer species since the Pliocene/Pleistocene 3 million years ago.

In some taxa, changes in the inner ear also coincided with changes in global temperature.

The paleontological and osteological collections of the Natural History Museum in Basel contain many specimens of ruminants (Credit: Credit: Océane Lapauze)

Photo courtesy of Springer Nature

　　Even in the inner ear, an important sensory system, minor shape differences can reflect climate and evolutionary history, the paper's authors conclude.

The findings of their newly completed study suggest that the inner ear has the potential to serve as a tool for evolutionary insights, supporting more work investigating the impact of non-functional shape changes in the inner ear of other taxa.

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