A LINEAGE PHYLOGENY FOR THE PALEOGENE PLANKTONIC-FORAMINIFERA

A stratophenetic lineage phylogeny (''phylogram'') is proposed for the Paleogene planktonic foraminifera, based on an extensive taxonomic re view and fundamental reassessment of their geohistoric record. In this phylogeny, an attempt is made to delineate lines of genetic descent t hrough lineages, rather than relationships among typologically defined morphospecies. The phylogenetics of 20 subgroups of the Paleogene pla nktonic foraminifera are summarized in a series of ''plexigrams,'' whi ch are graphical representations of previous taxonomic opinions. The p hylogeny is constructed with additional consideration of stratigraphic ranges and known examples of intergradation between taxa. As a result , approximately 800 morphospecies are grouped into six principal clade s and 134 lineages, of which 70 are terminal (ending in extinction or surviving into the Neogene) and 64 are nonterminal (ending in branchin g). The phylogeny is in no way intended to replace the existing taxono mic methodology but rather is intended to help elucidate patterns of e volution in the group by allowing cladogenetic and anagenetic modes of evolution to be identified.