Vertebrate localities in the Karroo System of the Luangwa Valley, Zambia

Abstract

PROLIFIC vertebrate localities within the Karroo System of the northern part of the Luangwa Valley in Zambia have been known since Dixey's investigations of 1928 and 1935¹. They were the subject of extensive collecting in 1960–61 by the then Geological Survey of Northern Rhodesia², and again in 1963 by a joint British Museum (Natural History)–University of London expedition³. Two fossiliferous horizons are recognised in the Luangwa Valley, the Madumabisa Mudstones corresponding to the Upper Permian Daptocephalus-zone of South Africa, and the Ntawere Formation which is regarded as a little older than the Manda Formation of Tanzania and corresponds approximately to the Beaufort-Stormberg boundary of the Karroo System. In 1972 members of the Geological Survey of Zambia investigated the middle Luangwa Valley in and around the game reserves, discovering two new, potentially important localities. The first lies in the Munyamadzi Corridor between the northern and southern game reserves and is an exposure of the Madumabisa Mudstones yielding abundant therapsid and some pareiasaur remains. The fossils are, however, preserved in calcareous mudstone nodules which lack the extensive, hard ferruginous covering which makes the specimens from the Upper Luangwa so difficult to prepare. The second is an exposure of the Ntawere Formation in the northern game reserve and yielded archosaur-like teeth along with the bivalve Unio karrooensis. As a consequence of these discoveries members of the Oxford University Museum were invited to participate in an expedition during the summer of 1974, to collect fossil vertebrates from the series of new localities in the middle Luangwa Valley.