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A NEW BASAL LINEAGE OF EARLY CRETACEOUS BIRDS FROM CHINA AND ITS IMPLICATIONS ON THE EVOLUTION OF THE AVIAN TAIL |
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| Authors: | CHUNLING GAO,LUIS M. CHIAPPE&dagger ,QINJING MENG,JINGMAI K. O'CONNOR&dagger &Dagger ,XURI WANG,XIAODONG CHENG, JINYUAN LIU |
| Affiliation: | Dalian Natural History Museum, 40 Xicun Street, Heishijiao Shahekou, Dalian, China; The Dinosaur Institute, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA;e-mail:; University of Southern California, Department of Earth Sciences, 3651 Trousdale Parkway, Los Angeles, CA 90089, USA |
| Abstract: | Abstract: We report on a new Early Cretaceous bird from China that sheds significant light on the evolutionary transition between primitive birds with a long bony tail and those with a short tail ending in a pygostyle. A cladistic analysis of basal birds supports the placement of the new fossil as the sister-taxon of all pygostylians. Possessing a unique hand morphology with a phalangeal formula of 2-3-3-x-x and a reduced number of caudal vertebrae lacking a pygostyle, the new specimen reveals anatomical information previously unknown and increases the taxonomic diversity of primitive, non-pygostylian birds. We infer from the specimen that during the evolution of the avian tail, a decrease in relative caudal length and number of vertebrae preceded the distal fusion of caudals into a pygostyle. |
| Keywords: | Aves pygostyle evolution Cretaceous |