This fish belongs to the group of Antarctic ice fish, also called notothenioids. The special thing about them: You can not only survive in the ice -cold south polar sea of Antarctica, but even feel comfortable there. Of the dozens of notothenioid species, some preferably swim near the surface, other strips on the sea floor and still whiz through the open water. This is made possible by frost protection proteins in your blood that protect the animals from freezing.
But there is still a second factor that enabled ice fish to live in the Antarctic: their diverse skull shape, as researchers around Kory Evans from Rice University now found. To do this, they had created and compared micro-Cans of the skull bones of 170 species from the family tree of the notothenioids. According to this, the emergency theater in the course of their more than 30 million years of evolution always developed a new shape of a skull – from very round with a short face to very elongated. The upper and lower jaw have adapted independently of each other and regardless of the rest of the body.
“By decoupling the pine, emergency theater could optimize the suction and bite mechanics without redesigning the entire head,” explains Evans. “Because even small changes in shape can redesign the way a fish grabs prey.” Some types of ice fishing developed pine with which they crush their prey living on the sea. Others optimized their skulls for a absorbent manner, with which they catch quickly moving destinations in the open water.
“The ice fish were able to vote on their feeding strategies when the Antarctic changed around them,” explains Evans. This opened up new nutritional strategies in the low -food waters, in which hardly organisms live because of the cold and dark. In addition, the climate in Antarctic has changed several times in the history of the earth, for example because the marine currents or glaciers changed. This habitat change was the boost for new skull shapes of the ice fish, as the team stated. This would not have been possible without the modular evolution of the jaw.