How was the "Gansu Bird" discovered? You Hailu, the first author of the paper and Chinese Academy of Geological Sciences, introduced at the press conference held in Washington, USA that many well-preserved "Gansu Bird" fossils were found in a remote lake bed near Changma Township, Yumen City, Gansu Province. Although they have no heads, their bones are relatively intact and not broken, and some of them still have webbed toes and other soft tissues. He believes that the static environment of the lake makes these fossils, especially the soft tissue parts, "intact" in shale deposition.
In fact, scientists have discovered the "Gansu Bird" fossils as early as 198 1 year, but only some birds' hind legs were found at that time. 1983, an ancient bird fossil with incomplete hind legs was first discovered here, and was later named "Gansu Bird". But for more than 20 years, few people went to Changma to do research. Until 2002, You Hailu went to Changma with a try. With the help of local farmers and even children, on the seventh day of his work, he discovered the fossils of the wings of Gansu Bird. Since 2003, researchers from You Hailu, Chinese Academy of Geological Sciences, the Third Institute of Geology and Mineral Exploration, Gansu Provincial Bureau of Geology and Mineral Resources and Carnegie Museum of Natural History in the United States have jointly investigated and excavated the Early Cretaceous strata in Changma Basin, Gansu Province, and finally found a large number of exquisite birds, fish and amphibian vertebrate fossils.
Due to the limitation of conditions, people have known little about the overall morphological characteristics and systematic classification of Yumen "Gansu Bird" for a long time. It was not until this time that Chinese and American scientists analyzed more than 200 characters of more than 20 main Mesozoic birds, including Gansu bird, that they finally found that Gansu bird was closely related to fish birds and yellow birds in North America in the late Cretaceous and isomorphic with modern birds, forming today's birds. The determination of this systematic relationship has advanced the current bird fossil record by about 30 million years. ? What does this ancient bird look like? How does it live? From the analysis of five species of "Gansu bird" fossils in this paper, it can be known that "Gansu bird" lived in the Early Cretaceous about1.10.50 billion years ago, and its size was similar to that of modern pigeons. In addition, it shares many characteristics with modern birds, including feathers, bones and flippers. The forelimb shape and feather characteristics of Gansu Bird show that it has strong flying ability, at least it can take off from the water.
More interestingly, one of the specimens still has webbed marks. Combined with other skeletal characteristics of hind limbs, it should also be very suitable for life in water. The details of its hind legs and webbed feet show that it may be a diving bird propelled by its feet, much like modern ducks, storks or diving birds, but their diving ability is much inferior. In addition, the skeleton of "Gansu Bird" is hollow, so it is heavy and clumsy. ? According to You Hailu, "Gansu Bird" lives in a warmer and wetter environment. They may eat fish, insects and occasionally plants, but their diet structure can only be determined after finding the head fossils. You Hailu said: "With the opening of layers of soil, the world 100 million years ago will be presented to us."
In addition to "Gansu bird", several primitive modern birds also show their adaptation to the aquatic environment. However, some early members of modern birds may soon migrate to land. For example, the ancestors of ostriches and chickens can also be traced back to the early Cretaceous. Whether this amphibious lifestyle is related to the escape of modern bird ancestors from the Cretaceous extinction event is still inconclusive.
Chinese and American scientists agree that "Gansu bird" is the earliest mode for modern birds to thrive on the earth, and the ancestors of modern birds in Cretaceous probably lived in aquatic environment. ? Matt Lemmona of Carnegie Museum of Natural History in Pittsburgh, USA, said excitedly: "Now, researchers have many almost complete' Gansu Bird' fossils." Most of the ancestors of birds in the dinosaur era were on the verge of extinction and did not form modern birds. But "Gansu bird" is an exception, so it is a bridge between primitive birds and modern birds, filling the gap between ancient and modern birds, and providing an important basis for in-depth study of the evolution and transformation of carnivorous dinosaurs to modern birds.