The fossil record of sub-equatorial Africa holds keys for testing a range of fundamental paleobiogeographic hypotheses. Five expeditions (2002-06) to the Rukwa Rift Basin in southwestern Tanzania funded by the National Geographic Society have revealed a diversity of new Cretaceous and Paleogene terrestrial vertebrates. These discoveries add crucial new data that bear directly on competing hypotheses concerning Gondwanan vertebrate biogeography during the Cretaceous-Tertiary transition. This grant assembles an international and interdisciplinary team to characterize novel faunas from Cretaceous and Paleogene deposits in the basin. New fossils will be placed into a rigorous phylogenetic framework, and thorough geological analysis of Rukwa Rift Basin deposits will allow taxa to be interpreted in both temporal and paleoenvironmental contexts. New fossil discoveries will be used to test biogeographic hypotheses concerning the evolution and distribution of Gondwanan vertebrates and exhibited for public education in both the USA and Tanzania.
Intellectual Merit: The field area encompasses both sides of the Cretaceous-Tertiary boundary within a restricted geographic area. This underscores the significance of the region for testing paleobiogeographic hypotheses concerning the origin and distribution of Gondwanan vertebrates during the geologically and biologically dynamic period from the Cretaceous into the early Tertiary. To date, only a fraction of the sedimentary deposits within the basin have been explored. In 2004/5, reconnaissance surveys identified two new outcrop areas that contain well-preserved fossils. The larger crews and longer expeditions under this grant will result in additional new discoveries. The primary scientific goals of this grant are: 1) to continue working proven localities; 2) to expand the search area to include unexplored rift basin strata; 3) to perform a complete basin analysis of the area, delineating the stratigraphic, sedimentologic, and depositional framework of the strata, to better constrain the age of the deposits; and 4) to conduct detailed anatomical and phylogenetic studies of new fossils and use these data to assess competing biogeographic hypotheses concerning the evolution of late Mesozoic and early Tertiary vertebrates.
Broader Impact: The team will develop academic human resources in both Tanzania and the United States by: 1) offering short course lectures at the University of Dar es Salaam; 2) linking the training of US students with their Tanzanian peers through field, laboratory, and research dissemination activities related to the project; and 3) developing a traveling exhibit highlighting the major finds and the process of paleontological discovery and research. This exhibit will enhance informal science learning resources for greatly underserved audiences in Tanzania, while giving US students and faculty a forum for developing skills aimed at engaging scientific and general audiences alike.
