Application of Ostracoda and Charophyta from the Late Jurassic to Early Cretaceous Tendaguru formation at Tendaguru, Tanzania (East Africa) - Biostratigraphy, palaeobiogeography and palaeoecology

摘要

Revisitation of the famous Late Jurassic/Early Cretaceous dinosaur locality of Tendaguru by a German-Tanzanian expedition in summer 2000 resulted in a new standard section. Micropalaeontologic samples from this section yielded a marine and nonmarine, partially mixed ostracod fauna consisting of 40 taxa and some charophyte gyrogonites and utriculi. A few marine taxa provided biostratigraphic information, although comparable faunas from the West Indian-Madagascan-East African faunal province are stratigraphically older (Middle/Late Jurassic), fully marine and strongly endemic. An (Middle) Oxfordian age is suggested for the lower part of the Tendaguru formation. Nodosoclavatoroid utriculi (Charophyta) suggest that the Jurassic/Cretaceous boundary may be located lower in the section than supposed previously, i.e. in the Trigonia smeei member rather than in the Upper Saurian member. In biogeographical terms, the marine ostracod fauna is relatively endemic and has most similarities with that known from eastern Tanzania. Only a few faunal links to Madagascar, Northwest India and Somalia exist, and there are no links to South Africa. Ostracods and charophytes also provided palaeoecological data for specific horizons. In the lower part of the Middle Saurian member a regression is documented. While the nonmarine Late Jurassic/Early Cretaceous ostracods of Tendaguru are not applicable to biostratigraphy so far, they are important because the nonmarine setting is unique in this area of the Tethys.