Birds are the only surviving descendants of dinosaurs. Not only did they cross the Cretaceous mass extinction some 65 million years ago, they have successfully evolved into one of the most diverse vertebrates today. The successful evolution of birds is related to their various structures related to flight, and is also inseparable from their special skull structure. From non-bird theropod dinosaurs to real birds, a series of changes have occurred in the skull, such as shortening of the face, enlargement of the skull, deterioration of bones around the orbit, and thinning of bones and loss of joints between each other. Particularly special is that the living birds are mainly neochids with highly movable skulls, which is reflected in the fact that their upper jaws can move flexibly relative to the skull, while the skulls of non-bird dinosaurs do not have such mobility.
Birds are the only surviving descendants of dinosaurs
Since the discovery of bird skull mobility in the 19th century, researchers have paid great attention to its related mechanisms, evolution, differentiation and function. Mobility of bird skulls may have the following functions: expand the scope of cleft lip, speed up the opening and closing of the beak, increase the ability of the skull to absorb impact forces, and improve the accuracy of feeding. This feature is mainly achieved by the relatively flexible zygomatic arch, square bone, and zygomatic bone: the square bone transmits the thrust to the movable zygomatic arch and zygomatic bone when it moves forward and backward, so that part of the upper jaw is relatively Lift up. The pterygoid-patella-coccygeal system can transmit thrust from the back of the skull to the front, so it plays an important role in the realization of skull mobility. Because early birds rarely preserved skeletal bones, little is known about the origin and early evolution of bird skull mobility.
Recently, the research team of Zhou Zhonghe of the Institute of Paleo-Spine of the Chinese Academy of Sciences and the research team of Hu Yan from the University of New England, Australia, published a research result entitled Evolution of the vomer and its implications for cranial kinesis in Paraves on PNAS. They performed high-precision CT scans on the skulls of Sapeornis and Chinese Sinovenator, and performed a three-dimensional reconstruction of the vulture, an important part of the pupal area, providing important information about the pupal area of early parabirds. Morphological information.
