Further clues to the evolution process from dinosaurs to birds are found with the new fossil, which had a dinosaur skull and bones but a bird’s body.
You may have heard that modern birds are among the closest descendants of the dinosaurs that we can live with today. Although science has known for some time, there are few glimpses of the complete transformation process in animals, hiding the subtle changes from us. A new 120-million-year-old fossil found in China recently gave us some of these evolutionary details.
What strikes us preserved remains of the bird is that it is complete, which allows it to display its unique characteristics, such as the dinosaur head on a body much more similar to that of a modern bird. In the developmental periods of young birds of modern birds, it is still possible to see some bodily appearances similar to those of dinosaurs – evolution, however, took that away from him as he developed.
Bird body, dinosaur head
So take action Cratonavis zhui, the curious new fossil. Excavations in northern China have revealed this and more primitive birdsas the A Confucian saint, as well as feathered dinosaurs, hidden in Cretaceous sedimentary rocks, about 120 million years old. With a digital reconstruction of the skeleton C. zhuits skull was found to be almost the same as that of large dinosaurs, such as the Tyrannosaurusand not like that of a bird.
This means that it could not open the upper part of its beak independently of the skull and lower jaw, as modern birds do, which even helped them to diversify ecologically. The animal would be, evolutionarily, between a Archaeopteryxwhich is more like a reptile, and the Ornithothoraxalready much closer to a contemporary bird.
The fossil also features a long scapula (bone equivalent to our shoulder blades), as well as a large metatarsus (middle foot bone), extremely rare in other ancestors and totally absent in modern birds. The hypothesis is that the metatarsal would have shrunk due to natural selection, becoming so small that it would lose its functions when less than 1/4 of the second metatarsal remained.
The long shoulder blade was visible other Cretaceous birds, and it is theorized that it would have been useful in the absence of a sternum, the pectoral bone that supports the strong muscles that move the wings, essential for flight today. The longer bone in the wings would help adapt things like retraction and rotation of the humerus, another wing bone, initial compensations that took place before the animal fully developed flight as we know it.
Fossilized species had the body of a bird and the skull of a dinosaur – CNET: #Artificial intelligence #IoT #Me and CC @motorcycletwitt @mikequindazzi https://t.co/TyYe8kzvlM pic.twitter.com/3zP2ixAuAC
— Arceo Choya (@ArceoChoya) January 5, 2023
In a sense, we can call the C. zhu of the “missing link” of birds, or at least one step less in the evolutionary ladder between them and them dinosaur ancestors. It’s a very interesting reminder of how small biological changes overlap, happening in different animals and in different ways until they find the best possible adaptations to their environment.
Source: Nature Ecology & Evolution
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