Tooth replacement of the sauropod Tornieria africana (Fraas) from Tendaguru (Late ,Tanzania)

Franziska Sattler

Material Results

The () of The left maxilla displays up to three replacement teeth. Most Tanzania offers one of the richest sauropod faunas known, teeth can be found in the left and right premaxilla. Two to four including the diplodocid Tornieria africana (Fraas, 1908). The teeth can be found, with an average formation time of 103 to material from Tendaguru treated in this study includes the left 163 days & replacement rates of between 32 to 41 days. (b) & right premaxilla (a) and incomplete left maxilla (c) of Tornieria inhabited forested ecosystems as a selective Tornieria africana. browser. Having teeth replace faster, it kept them fresh for In the premaxillae, four replacement teeth are present in each trimming off trees or bushes, as sauropods only used teeth to of the four tooth families. The maxilla bears ten alveoli, the cut food from plants before swallowing it whole. number of replacement teeth decreases from four to two per tooth family. The CT images also displayed a minimally developed structure, between alveoli three & four, of the maxilla. It is not a b c yet clear if this structure is either an undeveloped interalveolar septum or possibly a fracture, damaged bone or a crystallization

ee d

scale bar represents a length of 3 centimeters

Methods

f g

CT imaging was performed on a multi-detector CT scanner system (Toshiba Aquillion ONE, Otawara, Japan) at The Charité - Universitätsmedizin Berlin, medical school, To view &

edit the images, the freeware program OsiriX (32-bit version, 5.6) was used. The formation time of teeth in days was determined with measurements of lengths of teeth, basing on the calculations of d’Emic et al. (2013) by the equation for slender crowns: d alveoli length measurements on left maxilla MB.R.2345 (Ki 127), longitudinal CT section e CT images of left premaxilla MB.R. 2346 (Ki 126), longitudinal CT- section f Possible septum between alveoli three & four, scale bar represents a length of 2 y = - 0.0393 x2 + 5.403 x centimeters, g Example of incomplete septa in premaxilla of hansemanni (Jens Kosch) + 5.5891 Outlook y = formation time in days x = length of tooth Supplementary research on fragments of right maxilla (MB.R.2350), right dentary (MB.R.2347) & left dentary The replacement rate (MB.R.2348) would lead to more significant results in was calculated from the determination of tooth replacement rates in Tornieria africana. difference between Future histology studies of von-Ebner-Lines (tooth replacement formation time of different rate by lines of growth) would present a more in depth tooth positions. analysis. CT images generally presented low quality & References observing structures and D'Emic, D., Whitlock, J., Smith, K., Fisher, D., & Wilson, J. (2013), Evolution of replacement teeth often High Tooth Replacement Rates in Sauropod , PLoS ONE 8(7): proved difficult. e69235. doi:10.1371/journal.pone.0069235 Fraas, E. (1908), Ostafrikanische Dinosaurier, Palaeontographica (1846 - 1933), 55(2), pp. 105 - 144 Kosch J., Schwarz-Wings D. & Fritsch G. Tooth replacement in Insights from CT images in Dicraeosaurus hansemanni, A Talk in Symposium Lengths (in millimeter) of replacement teeth preserved 15: Tendaguru and beyond Vertebrates in Jurassic Terrestrial Ecosystems in the tooth bearing bones of Tornieria africana