Fossils discovered as a result of research conducted all over the world provide the scientific world with valuable information about the history of organisms that lived on our planet and that lived before.
Now, scientists from the Institute of Vertebrate Paleontology and Paleontology (IVPP) of the Chinese Academy of Sciences have found clues about a long-unsolved mystery about humans with the help of millions of years old fossils, with a study published in May in the journal Frontiers and Evolution.
The human middle ear appears to have evolved from fish gills
The human middle ear contains three small vibrating bones and plays a major role in carrying sound vibrations to the inner ear, becoming the boundary signals that enable us to hear. Embryonic and fossil findings had previously revealed that the human middle ear evolved through openings that allow fish to breathe. But the origin of these gills in vertebrates has long been an unsolved mystery.
Some 20th-century researchers sought these breathing openings between the jaws and tongues of the genera, believing that early vertebrates must have had a full spiral gill. However, during these researches that lasted more than a century, this situation was not found in any fossil. Now, in the published research, scientists have found clues about this mystery.
One of the authors of the research, Prof. According to GAI Zhikun, researchers from the institute have found a 438-million-year-old Shuyu brain shell fossil and a 419-million-year-old galeaspid fossil in different parts of China in the last 20 years, with preserved gill filaments. “These fossils provided the first anatomical and fossil evidence that the respiration opening in vertebrates was based on fish gills,” GAI Zhikun said in a statement.
Breathing openings turned into a canal for hearing
Stating that traces of fish can be found in our teeth, jaws and middle ears, and reconstructing the Shuyu brain fossil virtually, the researchers provided valuable information by revealing almost all the details of the head anatomy, five brain parts, and sensory organs of this variety, saying, “The main aim of paleontologists is to uncover the missing links in human evolution. ‘ he said.
The breathing openings, called the ‘spiracle’, are a small hole behind the eyes of some fish that extends to the mouth and helps to perform the breathing action that ensures the survival of the variety. Polypterus, the most primitive bony fish, also uses these openings to breathe air. But the findings showed that this opening changed in many non-fish species as they evolved to breathe through the nose and mouth.
According to experts, the opening called ‘spiracle’ in early tetrapods first turned into Otic notches, which were stated to be a part of the auditory structure. This was initially used in respiration just as with other clarity and could not detect sound. In this process, which is also stated to be seen in human evolution, it was stated that this opening later turned into the ear of tetrapods and eventually became a channel used to transmit sound to the brain through the inner ear bones.