New Study Explains Evolution Of Human Ears And Teeth From Jurassic Era Period

The recent two new studies from the Jurassic-era fossil fuel have offered new insights into the evolution of mammals such as human–specifically their ear and teeth. Researchers from Australia, China, and the USA examined the Jurassic-era fossil fuel to determine the earliest dental diversification of mammaliaforms and documented evolutionary changes of jaw joint to the mammalian middle ear. Both studies yielded a total of four fossils dating back more than 164 million years. They are all fossils of mammals, a group that includes mammals and their closest extinct relatives. Three of the four found were Shuotheriids – small, rat-sized creatures that died out along with the dinosaurs.

While examining the teeth and ears of Shuotheriids, the researchers were puzzled as to how humans got from the time of dinosaurs to the modern era, where mammals predominate. They also wondered about the process of linking different evolutionary branches which we see today. The research by palaeontologist Patricia Vickers-Rich of Monash University in Australia provides important information about the evolution history of mammaliaforms, little known until recent discoveries in China.

Shuotheriids have puzzled paleontologists since the 1980s. The shape of their teeth does not match that of equivalent mammals today. On closer analysis, the shape of Shuotheriids teeth matched to another group of mammaliaforms called the docodontans. It branched off early from the group of mammals that eventually became our ancestors. Basing the study on this fact, researchers claim that Shuotheriids should be grouped closer to docodontans.

Regarding fossil ears, researchers identified key features in the middle ear that give us mammals the ability to hear among the sharpest on Earth. The second study compared an older, more reptile-like mammal fossil with a newly discovered Shuotheriids species. This helped in explaining the evolutionary change from reptiles with one middle-ear bone to mammals, which have three ears.

Jin Meng, a palaeontologist at the American Museum of Natural History in New York, says scientists have been trying to understand how the mammalian middle ear evolved since Darwin’s time.

“These new fossils shed light on a critical missing link and enrich our understanding of the gradual evolution of the mammalian middle ear. This type of remapping helps show how traits evolved, either independently or in concert,” says Jin Meng.