Taxonomy, palaeoecology and palaeobiogeography of some palaeozoic fish of Southern Gondwana

[摘要] ENGLISH ABSTRACT: The fossiliferous Waaipoort Formation (Witteberg Group, Cape Supergroup), GanikobisFormation (Dwyka Group, Karoo Supergroup) and Whitehill Formation (Ecca Group,Karoo Supergroup) span a protracted period interrupted by a +-45Ma glacial event. ThisLate Carboniferous glacial event resulted in a prolonged hiatus in sedimentation as wellas significant erosion in many southern continents of Gondwana. This studydemonstrates how the glacial episode affected faunal composition and changes inpalaeoecology in southern Gondwana across this time period. The Waaipoort shows thehighest overall faunal diversity with relatively high palaeoniscoid diversity withinGanikobis and Whitehill Formations. This study is unique in correlating EarlyCarboniferous - Early Permian fish fauna of South Africa and Namibia specifically, aswell as other parts of southern Gondwana, and includes maps of possible fish migrationroutes. This study attempts to refine the body of disjointed knowledge on the taxonomyand distribution of the fish fauna surrounding this period in southern Gondwana. Threenew Waaipoort taxa are recognised, and several reassigned. Earlier work on LateCarboniferous fish from Southern Africa has been updated herein to incorporate recentcollections. This has allowed the recognition of up to 15 new palaeonoscoid taxa, some ofwhich are endemic to this region. Several new taxa are recognised within the WhitehillFormation fish fauna and a new lectotype for Palaeoniscum. capensis is presented.Detailed taphonomic and sedimentological studies (with 6 lithologs) of fossil localitiesvisited in this broad-based study verify the correlation, and impart information often lostor ignored in pure palaeontological studies on the palaeoecology or palaeoenvironment ofthe fauna. Systematic relationships discussed here also serve to strengthen thepalaeobiogeographical correlations between the Gondwanan continents.

[发布机构] Stellenbosch University