Every time we swallow, it's about 164 million years ago

164 million-year-old fossil is the last record of a tiny column-toothed beast. It is a tinylike a baby, and the earliest example of animals evolving modern tongue bones.
mammals are now very diverse and can chew food in different ways, but they all swallow it in the same way, " he said. "In essence, mammalian chewing and swallowing is achieved by flexible tongue bones, " said Roggethy, senior author of the study and a professor of anatomy and biology at the University of Chicago.
Led by Zhou Chang-fu, a professor in the School of Geosciences and Engineering at Shandong University of Science and Technology, the international cooperation team of Chinese, American and German scientists, after 6 years of research, finally confirmed that the Jurassic tiny column-toothed beasts found in fossils found in the Wuhua area of Ningcheng, Inner Mongolia, have the same tongue bone structure as living mammals. The fossil is also the first primitive mammalian fossil to date with a complete tongue bone. The paper was published July 19 in Science.
" finding proves that every time we swallow is related to 164 million years ago. "Mammal tongue bones appear in the earliest stages of the chewing ability of mammalian animals, " Zhou told China Science. Thethe back of the mouth with a tongue bone and "guards" the "gates" of the esophageal and throat. The tongue bones of modern mammals, including humans, are U-shaped, similar to saddles, and play a key role in the fine chewing and swallowing of food.
researchers say saddle-shaped tongue bones determine the frame of the throat, marking a finer and more complex way for mammals to chew and swallow food than reptiles: mammals typically swallow small or fine pieces of food at once, rather than swallowing large pieces of food or entire prey in one bite like an alligator.
, however, when and how this unique tongue structure first appeared in mammals has been a question for paleontologists.
2014, Zhou Changhua, who was working at Shenyang Normal University, and colleagues discovered a tiny column-toothed animal fossil with delicate tongue bones in the Yanliao biome on the border of Liaoning, Inner Mongolia and Hebei.
"This is a primitive, beautiful fossil. I was surprised at first sight that this little fossil had been preserved so well. We have a feeling that this fossil is unusual, but we are confused about its unusualness. "After taking detailed photos and examining the fossils under a microscope, we realized that the jurassic animal's tongue bone was very small, much like that of a modern mammal. " small column-toothed beast belongs to the column-toothed eye and is a mesozoic mammal." Mammals are earlier animals than mammals, such as apes and humans, but they are not mammals, but mammals. Zhou Chang-fu said.according to
, the Mesozoic (also known as the reptile era) from 252 million to 66 million years ago, in this ancient age, mammals are close relatives of modern mammals, so the study of mesozoic mammal fossils is the focus of paleontology and life evolution research.
because the tongue bone is relatively brittle, relatively small, difficult to preserve, so few people in previous fossil studies have paid attention to this field.
" tongue bone is relatively small and not closely connected to other bones, so the animal dies, it is easy to fall off or decay, so it is difficult to save. Previously discovered fossils of older mammals have not been preserved with intact tongue bones, mostly teeth or incomplete skulls. "Therefore, the study fills a gap in the systematic study of the evolution of mammalian tongue bones. After
tongue bone was found in tiny column-toothed animals, researchers found similar tongue bone fossil structures in other mesozoic mammals.
the first time we have been able to learn from the fossil record how key swallowing functions in early mammals evolved," he said. The tiny tongue-like body of a tiny column-toothed beast is an important milestone in explaining the evolution of mammalian feeding function. Rozesi said.
researchers also noted that the findings suggest that the tongue bone structure of modern mammals originated and was passed on to more primitive mammals, breaking conventional scientific understanding that tongue bones originated in mammals rather than mammals.researchers also studied models of tiny column-toothed beasts and reconstructed their way of life.
the fossil is about 14.7 cm long and weighs about 5 to 9 grams. According to reports, this is the smallest column-toothed beast fossils found so far. Its tongue bone part is only a few millimeters in size, difficult to distinguish with the naked eye, scientists through industrial CT and other technical means to detect, after a long period of research, finally determined the existence of the tongue bone.
addition, the jaws and middle ears of modern mammals were developed by the first pharynx, a structure in vertebrate embryos that can develop into other recognizable bones and tissues. At the same time, the tongue bone develops from the second and third pharynx bows, respectively. Tiny column-toothed beasts have a primitive middle ear that still adheres to the jaws like other early mammals, such as canine-toothed dragons.
, such as the "d'a" jaw-type middle ear, also provide new clues to the study of the diversity of primitive mammals and the evolution of the middle ear. Zhou Chang-fu said. Bhart-Anjan Bhullar, a postdoctoral scholar at Yale University, said:
In the tongue and ear bones are derivatives of primitive vertebrate mouths and gills, which were used by the earliest fish ancestors to feed and breathe. The tongue joints and active tongue bones of tiny column-toothed beasts coexist with the ancient middle ear. Therefore, the establishment of modern mammals is the reuse of ancient systems. "
, the tiny column-toothed beast was the first new species to be discovered and named." It has typical primitive mammalian characteristics, light bones, long and slender limb bones, tail more than half the length of the body, mainly tree habitat. Zhou Chang-fu said.
, Yanliao biome is a world-renowned treasure trove of meso-living biological fossils, which is of great value for studying the origin of dinosaurs, birds and plants. Fossil layers of tiny column-toothed beasts date back between 166 million and 164 million years, when tiny column-toothed beasts coexisted with other column-toothed animals, such as semi-aquatic beaver-tailed beasts.
relevant paper information: