Foraminiferal Classification and Evolution

The relative values assigned to various morphologic and physiologic criteria, in foraminiferal systematics, have differed greatly over the past two centuries. The earliest classification was based on a single criterion, whereas data are now available for a wide variety of morphologic, mineralogic, physiologic and ontogenetic criteria.

The membranous or pseudochitinous Lagynacea are believed to have given rise separately to agglutinated, microgranular calcareous, and hyaline calcareous foraminifera. A hypothetical phylogeny is presented for the Parathuramminacea, Endothyracea and Fusulinacea. Developmental trends from simple to compound walls, from unilocular to septate forms and subdivided chambers, and from free-living to attached habit occurred independently in various lineages. The postulated origin of the Nodosariacea and Buliminacea is discussed.

The subfamily Tholosininae Bermudez and Rivero, 1963, is a synonym of the Hemi-sphaerammininae Loeblich and Tappan, 1961, the families Variostomidae (recte Vario-stomatidae) Kristan-Tollmann, 1963, and Duostominidae Brotzen, 1963, are synonymous; the Trocholinidae Kristan-Tollmann, 1963, is a synonym of the Involutinidae Butschli, 1880, and the Eponidopsidae Reiss, 1963, is a synonym of the Eponididae Hofker, 1951.

Neogeinitzina Brotzen, 1963, is a junior synonym of Frondiculinita Gerke, 1961, and both are regarded by us as synonyms of Lingulina. Neospandelina Brotzen, 1963, is based on the same type species as Ichthyolaria Wedekind, 1937, hence is a junior objective synonym.

Discorbis and Epistomaria are herein shown to be monolamellid, rather t)tan bilamellid, hence genera stated by Reiss not to be monolamellid are therefore transferred to the super-families Orbitoidacea (family Rosalinidae), or Rotaliacea (family Rotaliidae). The Rosalinidae Reiss, 1963, is restricted to include only Rosalina, Eoeponidella and Earlmyersia. The Glabratellidae Loeblich and Tappan, 1964, is transferred from the Discorbacea to the Orbitoidacea and the Pegidiinae and Rupertininae transferred from the Rotaliidae to the Orbitoidacea, the former as family Pegidiidae, and the latter placed in the Cibicididae.

Reissia, new genus (type species, Ehrenbergina hystrix Brady) differs from Ehrenbergina in having the radial wall microstructure and apertural toothplate characteristic of the Islandiellidae.

The microgranular hyaline superfamily Cassiclulinacea is restricted to include only the Pleurostomellidae, Annulopatellinidae, Caucasinidae, Delosinidae, Loxostomatidae (herein corrected), and Cassidulinidae. The superfamily Nonionacea is recognized as including the enrolled monolamellid, granular walled Involutinidae, Nonionidae and Alabaminidae, and the new superfamily Anomalinacea (elevated from family status) includes the bilamellid enrolled Anomalinidae and Osangulariidae. Trichohyalus is transferred from the Alabaminidae to the Anomalinidae. Other as yet incompletely known genera require additional study of their morphology and microstructure.