About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 50 (1966)

Issue: 3. (March)

First Page: 605

Last Page: 606

Title: Phylogenetic and Taxonomic Problems of Some Tertiary Planktonic Foraminiferal Lineages: ABSTRACT

Author(s): W. A. Berggren

Article Type: Meeting abstract

Abstract:

The basic phylogeny and classification of five major lineages of Tertiary planktonic Foraminifera are considered and several revisions are suggested. The definition of Globorotalia is broadened to include keeled and non-keeled forms; its range is Danian to Recent. Globorotalia pseudobulloides (Plummer) is interpreted to be highly polytypic and ancestral to all later Tertiary members of the Globigerinacea with

End_Page 605------------------------------

the exception of the Heterohelicidae, which have had their own separate evolutionary development. Globoconusa daubjergensis (Bronnimann) is classified with the Guembelitriinae in this paper.

Four lineages within the genus Globorotalia are differentiated: one leading toward low-conical, keeled and non-keeled forms (G. spiralis-pusilla-convexa-broedermanni) became extinct during the middle Eocene; a second leading toward compressed, keeled, and non-keeled forms (G. compressa-ehrenbergi-pseudomenardii-chapmani-planoconica-pseudoscitula) became extinct at the end of the middle Eocene; a third is postulated as having led from low- to high-conical forms ("conical globorotaliids") which became extinct at the end of the middle Eocene; and a fourth lineage is postulated as having led to the Neogene and Recent globorotaliid faunas.

The acarininids appear to be characterized by species which are distinguished from Subbotina and Globorotalia by a strongly spinose wall texture. Two, and possibly three, branches within this lineage appear to lead independently, through parallel trends, to the development of the polytypic, but monophyletic, genus Truncorotaloides. In terms of normal criteria of divergence (gaps) and monophyly, there seems to be justification for recognition of the acarininids as a genus, provided the genus were emended to include primarily spinose forms. The genus Truncorotaloides also is accepted as valid, although it seems unlikely that it warrants a separate subfamily.

End_of_Article - Last_Page 606------------

Copyright 1997 American Association of Petroleum Geologists