Southern African Phanerozoic marine invertebrates: biogeography, palaeoecology, climatology and comments on adjacent regions

The Palaeozoic marine invertebrate fossil record in southern Africa is char acterised by extensive data for the Early and Middle Devonian but extremely limited or absent for other Palaeozoic Periods. The Mesozoic Era is lackin g in marine invertebrate fossils for the Triassic, Late Jurassic, and Creta ceous. For the Cenozoic Era there is limited marine megafossil information. Overall, in benthic, cool waters, Palaeozoic, marine megafossils from sout hern Africa appear to represent relatively low diversity communities, when compared to ecologically comparable warm water environments elsewhere. Howe ver, the marine benthic Cretaceous and Cenozoic faunas of southwestern Afri ca are typically diverse warm water types, until the later Miocene when coo l waters again prevailed. The Benguela Current clearly influenced lower div ersity faunas. Climatically, it can be inferred from the marine megabenthic palaeontologic al evidence, that warm conditions were present from Early Cambrian until mi d-Ordovician times, followed by a much cooler climate that persisted well i nto the Middle Devonian. The Late Palaeozoic evidence thus indicates cool t o cold conditions. In contrast, the Late Permian fossils are consistent wit h warmer conditions, continuing through Late Jurassic and Cretaceous times along the East African and West African coasts, until the Late Miocene. Within the Gondwanan framework, a Central African region can be envisaged t hat was subject to non-marine conditions during the entire Phanerozoic Eon. Peripheral to this central African region were marine environments of vari ous ages. The geological history of these peripheral regions was fairly uni que. Some features in southern Africa are similar ot those found in the Par ana Basin and the Falkland Islands. Most of North Africa from central Senegal to Libya contains a Phanerozoic m arine cover extending from the Early Cambrian through to the Carboniferous, characterised by warm water faunas, except for the Ordovician which yields cool-cold water faunas. The Palaeozoic of Arabia, which was an integral pa rt of Africa until the Miocene, has yielded warm water fossils. (C) 1999 El sevier Science Limited. All rights reserved.