Innovations among Paleogene planktonic foraminifera
Titel:
Innovations among Paleogene planktonic foraminifera
Auteur:
Radford, Sally Gamson, Paul Qianyu, Li
Verschenen in:
Historical biology
Paginering:
Jaargang 5 (1991) nr. 2-4 pagina's 363-367
Jaar:
1991-12
Inhoud:
Comparison of results from ODP Sites in the Indian and Antarctic Oceans with published data, reveal that planktonic foraminifera underwent considerable radiation, diversification, proliferation and expansion, throughout the 21 Myr duration of the Eocene, the longest, warmest epoch of the Cenozoic. Fundamental changes in wall texture and test architecture occurred in equatorial, tropical, temperate, austral and boreal oceans. One hundred new species appeared, 83 of them in tropical waters, mainly within the first eight of eleven biozones. Lineages in the evolving continuum of Morozovella in the tropics and Acarinina in high latitudes contributed to the proliferation of muricate taxa. Cosmopolitanism in the warm oceans of the Early-Middle Eocene was followed by declining diversity in the Late Eocene when temperate species expanded into the tropics. Slow taxonomic evolution continued throughout the 13 Myr duration of the Oligocene, within five zones. Provincialism in the cooling oceans was followed by progressive and iterative evolution of new lineages. Innovative morphologies are illustrated for Pseudohastigerina, Globigerinatheka, Hantkenina, Turborotalia, Globigerina and Tenuitella.