Study ‘living stubborn’ revisits the anatomy of fish, a new sight of the evolution of the scalp skull

Qualakanth is known as “living focus” because its anatomy has changed very little in the last 65 million years. Despite being one of the most studied fish in history, it continues to reveal new information that can change our understanding about the evolution of the rash. This has been revealed in a research published in the journal Science development Researchers at the University of Sao Paulo (USP) in Brazil and Smithsonian institution in the United States.

When re -examining the cranial muscles of the African Qualakant (Latimiria Chalmani), the authors discovered that only 13 % of the pre -identified evolutionary muscle novels for the largest rash tissues were just 13 % accurate. The study also identified nine new evolutionary changes in feeding and breathing in these groups.

“Ultimately, it is more matching than cartilagins fish [sharks, rays, and chimaeras] And tetrapeds [birds, mammals, amphibians, and reptiles] It was thought earlier, and even more separate fish, which forms almost HALF half -livedaries, “says Alecio Datu, a professor at the USP’s Museum of Zoology (MZ), who is leading the study.

The evolutionary novels have been wrongly identified as present in the quiclant, which are responsible for actively expanding the bocyfrigenic cavity in the muscle, which extends from the mouth to the neck. This muscle combination is directly related to food arrest and breath. However, the study shows that the muscles in the colakanth were actually ligaments, which are unable to contraction.

Ray Fund Fish (Actinoproti) and Loubi Fund Fish (Sarcoptriji) were removed from a combined ancestor about 420 million years ago. Surkoprotection includes fish such as quiloxaths and lungs as well as all other tetrapeds, as they are produced by aquatic ancestors. These include staggers, birds, crawling animals and embezzles.

In a ray -like ray like aquarium carp, it is easy to see how to suck in the mouth. This qualification has benefited activities to an important evolutionary benefit. Today, they contain half of all living watches.

This is a fundamental difference from other fish, such as quail and sharks, who mainly cut their victims and eat.

“In previous studies, it was assumed that this combination of muscle, which would provide more suction capacity, was also present in the Qualakanth, and for this reason, the shared ancestors of Bonnie Benemia, which we now show.

Behind the curtains

Coelacanths are extremely rare fish that live 300 meters below the water level and spend their days in underwater caves.

Since dinosaur disappears, they have changed so little that they have very few hunters and live in a relatively CEET safe environment. This resulted in a gradual changes in their genome, as shown from a 2013 study published in the journal Nature.

Coelacanths was first known as fossils about 400 million years ago. It was not until 1938 that a living animal was discovered, because of the surprise of scientists. In 1999, another species was discovered in the Asian waters.

Due to the fragility of samples in the museum, researchers from the National Museum of Natural History of the USP and the Smithsoni Institution had to find an organization ready to lend animals.

The Field Museum in Chicago and the Virginia Institute of Marine Sciences, both in the United States, finally agreed to give a sample. According to Datu, the co -author of the article, G. David Johnson, deserves credit for obtaining a loan.

According to Datu, Johnson, who was born in 1945, was probably the largest fish of his time. He died in November 2024 after a domestic accident, while the research was considered.

“On the contrary, the transfer of a model does not mean that it does not mean that it is done properly,” says Datu.

The researcher, who has been studying this kind of study for 20 years, spent six months separating all the muscles and scalp bones of colakant. These structures are now safe and can be studied individually by other scientists, which can eliminate the need to separate a new animal.

Looking at each muscle and nerves themselves, the authors were allowed to identify what was in the head of the colakanth with reality, identify the structures described before, and the right mistakes that were repeated in scientific literature for 70 years.

“There were many contradictions in the literature. When we finally started to examine the samples, we found more mistakes than our imagination. For example, the 11 structures described as muscles were actually ligaments or other types of tissues. It has a strong consequence of mouth and breathing, because they only explain it, because they only explain it.” “

Due to the status of a colakant in the life of life, this discovery affects our understanding of cranial evolution in all other major western groups.

With this information, the researcher used images of three -dimensional microtomography of the skulls of other groups of fish, both are living and living. These images are provided by other researchers who study fish anatomy while scanning 3D.

From the completely extinct tissues, the pictures of the skull of other fish, Datu and Johnson succeeded in guessing where the muscles found in the colakanth would fit, and the evolution of these muscles was clarified in the first jaw. In the future work, Datu Tetrapids plans to analyze the matching with muscles, such as Ambibine and Currening Animals.