A possible azhdarchid pterosaur from the Lower Cretaceous Qingshan Group of Laiyang, Shandong, China

ABSTRACT

A new pterodactyloid pterosaur is identified from the Early Cretaceous Doushan Formaiton of Laiyang, Shandong Province, China, based on a fragmentary humerus. The humerus exhibits several diagnostic characters: deltopectoral crest is elongate and un-warped, its base is slightly displaced relative to the humeral shaft axis, and the crest is swollen terminally and ventrally displaced; humeral shaft is straight and thin-walled with a ‘D’-shaped cross-section. Based on these features, the specimen is referable to the superfamily Azhdarchoidea as Azhdarchidae indet. As the oldest known azhdarchid fossil, the specimen represents a significant stratigraphic range extension for the family. Other non-azhdarchid azhdarchoids such as tapejarids and chaoyangopterids are common in the Jiufotang Formation of western Liaoning, which possibly is equivalent to the Doushan Formation of Laiyang with an age of about 120 Ma. Consequently, the possible coexistence of these azhdarchoids lineages documents that the azhdarchids split from the main azhdarchoid clade occurred no later than the Early Cretaceous.

ACKNOWLEDGMENTS

I thank Prof. Ke-Qin Gao (Peking University, Beijing), Dr. Peter Makovicky (the Field Museum, Chicago), and other members of the Laiyang international field team, R. Pei, H.-Y. Yi, J.-Y. Chen, A. Shinya, R. Sadleir, N. Smith, and B. Kilbourne, for their field assistance. I would like to thank Dr. S. Christopher Bennett (Fort Hays State University, Kansas) and Dr. F. Knoll (Museo Nacional de Ciencias Naturales–CSIC, Madrid) for their critical reviews. The final version of the manuscript was corrected by Dr. P. Makovicky to improve its clarity and readability. This study was supported by grants from the National Scientific Foundation of China (Grant No. 40802007) and from the Ph.D. Start-up Foundation of Shenyang Normal University.