Abstract
The reduced lower temporal arcade of the skull and the movable quadrate are the most distinctive features of squamates. Up to now, no exception has been documented for any fossil or extant squamates. We report here a new fossil lizard that possesses a complete lower temporal arcade and an unmovable quadrate. The anatomical relationships indicate that those two modifications were secondarily obtained in the new lizard. The complete lower temporal bar and the firm contact between the pterygoid and quadrate may have served as a brace to support the quadrate jaw articulation and thus prevent it from twisting anteriorly rather than posteriorly during the bite cycles. This represents an entirely new pattern of jaw muscle functions within the Squamata.
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Acknowledgments
We thank the Ministry of Science and Technology of China (973-Project-2006CB701405) and the Bureau of Land and Resources of Henan Province, China for supporting the project. We are greatly indebted to the Shandong Tianyu Natural Museum at Pingyian, Shandong Province, China for allowing us to study the specimen. Mr. Gui-hai Cui skillfully prepared the specimen. Dr. Peter Dodson (Philadelphia) read the earlier draft, offering helpful advises and suggestions. The functional discussion of the manuscript is benefited from the comments and suggestions of the four reviewers. X-c Wu thanks Dr. Hai-lu You for providing access to his office when working on the specimen and the Institute of Geology, Chinese Academy of Geological Sciences for support during his stay in the institute. The revision of the manuscript was done in National Museum of Natural Sciences, Republic of China during X-c Wu’s sabbatical stay.
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Lü, Jc., Ji, Sa., Dong, Zm. et al. An Upper Cretaceous lizard with a lower temporal arcade. Naturwissenschaften 95, 663–669 (2008). https://doi.org/10.1007/s00114-008-0364-1
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DOI: https://doi.org/10.1007/s00114-008-0364-1