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Dicraeosaurus dentition and tooth replacement

Ben Creisler

A new online paper:

Daniela Schwarz, Jens C. D. Kosch, Guido Fritsch & Thomas Hildebrandt (2015)
Dentition and tooth replacement of Dicraeosaurus hansemanni
(Dinosauria, Sauropoda, Diplodocoidea) from the Tendaguru Formation of
Journal of Vertebrate Paleontology (advance online publication)

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.

SUPPLEMENTAL DATA—Supplemental materials are available for this
article for free atwww.tandfonline.com/UJVP