The lacustrine deposits of the Yixian and Jiufotang Formations in the Early Cretaceous Jehol Group in the western Liaoning area of northeast China are well known for preserving feathered dinosaurs, primitive birds and mammals. Here we report a large basal bird, Jeholornis prima gen. et sp. nov., from the Jiufotang Formation. This bird is distinctively different from other known birds of the Early Cretaceous period in retaining a long skeletal tail with unexpected elongated prezygopophyses and chevrons, resembling that of dromaeosaurids, providing a further link between birds and non-avian theropods. Despite its basal position in early avian evolution, the advanced features of the pectoral girdle and the carpal trochlea of the carpometacarpus of Jeholornis indicate the capability of powerful flight. The dozens of beautifully preserved ovules of unknown plant taxa in the stomach represents direct evidence for seed-eating adaptation in birds of the Mesozoic era.
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机译:东北辽西地区早白垩世热河群的义县和九佛堂组的湖相沉积物以保存羽毛恐龙,原始鸟类和哺乳动物而闻名。在这里,我们报告了一只大型基础鸟Jeholornis prima gen。等。十一月,来自九佛堂组。这只鸟与白垩纪早期的其他已知鸟的不同之处在于,它保留了长长的骨骼尾巴,并带有意想不到的细长的合子前体和人字形,类似于绒毛龙科,为鸟类和非禽兽脚类之间提供了进一步的联系。尽管在早期禽类进化中具有基础地位,但Jeholornis腕果的胸带和腕轮的先进特征表明其具有强大的飞行能力。胃中数十个保存完好的未知植物类的胚珠代表了中生代鸟类对种子进食适应的直接证据。
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