Dentition and tooth replacement of Dicraeosaurus hansemanni (Dinosauria, Sauropoda, Diplodocoidea) from the Tendaguru Formation of Tanzania

ABSTRACT

Computed tomographic scan data of three premaxillae, a maxilla, and a dentary of Dicraeosaurus hansemanni allow reconstruction of the tooth replacement pattern in this taxon. Four or five replacement teeth are present in each of the four tooth families of the premaxilla. The interalveolar septum is labially interrupted, and an alveolar trough is formed. In the maxilla, the number of replacement teeth decreases in a caudal direction from four to one per tooth family. The dentary bears 16 alveoli, and the number of replacement teeth decreases caudally from three to one per tooth family. Replacement rates are around 20 days for the premaxillary and rostral maxillary teeth of Dicraeosaurus, which confirms the presence of high tooth replacement rates in Diplodocoidea. Replacement teeth of the dentary are less than half as large as those of the upper jaw, and replacement rates are around 50 days for the rostral dentary teeth. Hypothetical reconstruction of Zahnreihen yields a potential z-spacing of 1 with simultaneous front-to-back tooth replacement. Most probably, the rostral-most teeth in Dicraeosaurus were used for food acquisition, whereas the more caudally positioned teeth served only as a guide and as a lateral limit for the food within the mouth. The teeth of the dentary were less prone to wear than those of the upper jaws. These findings are in agreement with the reconstructions of Dicraeosaurus as a selective mid-height browser.

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Citation for this article: Schwarz, D., J. C. D. Kosch, G. Fritsch, and T. Hildebrandt. 2015. Dentition and tooth replacement of Dicraeosaurus hansemanni (Dinosauria, Sauropoda, Diplodocoidea) from the Tendaguru Formation of Tanzania. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1008134 .

ACKNOWLEDGMENTS

We cordially thank M. Schudack and O. Hampe for helpful comments, suggestions, and advice on the manuscript. The thorough and helpful reviews of J. Whitlock and M. D'Emic added much to the improvement of an earlier version of the manuscript. We'd like to thank especially J. Fahlke and M. T. Clementz for suggestions and linguistic corrections on the final manuscript. We thank also the editor R. Butler for his careful handling of all manuscript versions.