The evolution and biodiversity of Cretaceous planktonic Foraminiferida

摘要: Abstract Planktonic Foraminiferida originated in the Triassic[?] or Early Jurassic but only expanded markedly to mid-Cretaceous. It is during mid-Late Cretaceous that they evolved into a wide range of morphotypes and were able colonise much greater environments regions. During mid-Cretaceous, particular, developed strategies which allowed them move from eutrophic oligotrophic environments, especially those deeper water column. The general increase and/or turnover taxa was punctuated by number major “events”, e.g., Bonarelli event latest Cenomanian. Between these biotic crises there are smaller events, some can be attributed limited anoxic although others appear more related eustatic changes. changes fauna described problems identified.