Tooth formation and replacement rates of diplodocoid saurpods trom the Tendaguru Formation (Late Jurassic, Tanzania)

The Late Jurassic (Tithonian) Tendaguru Formation of Tanzania offers one of the richest sauropod faunas known. The diplodocoid material from Tendaguru treated in this study includes left and right premaxillae, incomplete left and right maxilla, and the left as well as the right dentary from different locations within the Tendaguru Hill area that, historically, had been subsumed under the term Barosaurus africanus. Recent re- examinations have demonstrated that the material belongs to different taxa within Diplodocoidea, and it is henceforth described according to its provenience of different quarries. CT scanning of the separate tooth-bearing bones of the upper and lower jaws allow detailed reconstructions of tooth formation pattern.

The quarry at Kijenjere, Upper Saurian Beds, yielded two premaxillae, with four replacement teeth present in each of the four tooth families. The left maxilla bears eleven alveoli, the dental fragments show eleven alveoli. The number of replacement teeth decreases from four to two per tooth family. Formation times can be calculated to between 96 and 162 days for the premaxillary teeth. With calculated replacement rates of between 23 and 33 days, this material corresponds well with the rates of Diplodocus (34 days), Camarasaurus (62 days), and Nigersaurus (14-30 days). The reconstruction of a of rather high tooth replacement rate in Diplodocoidea corresponds well with the recovered vegetation, dominated by woody browse in the Tendaguru Hill area.