Chapter 15: WALL TEXTURES AND HIGHER TAXONOMY OF OLIGOCENE MICRO- AND MEDIOPERFORATE PLANKTONIC FORAMINIFERA
Published:January 31, 2018
Paul N. Pearson, 2018. "WALL TEXTURES AND HIGHER TAXONOMY OF OLIGOCENE MICRO- AND MEDIOPERFORATE PLANKTONIC FORAMINIFERA", Atlas of Oligocene Planktonic Foraminifera, Bridget S. Wade, Richard K. Olsson, Paul N. Pearson, Brian T. Huber, William A. Berggren
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New microstructural observations on the tests of microperforate and medioperforate planktonic foraminifera from the Oligocene are presented and comparisons are made with some Holocene specimens. Two types and two subtypes of wall texture are distinguished: the glutinata-type (in Globigerinita and Tenuitella; with the danvillensis-subtype in Dipsidripella), and the ototara-type (in most Chiloguembelina), with the chipolensis-subtype (in Cassigerinella and some Chiloguembelina). Given also the gross morphological differences between the two major groups (trochospiral versus biserial or enrolled-biserial), these wall textures likely indicate separate evolutionary radiations from different groups of benthic foraminifera and so help define the higher taxonomy of the planktonic foraminifera. Accordingly, the following superfamilies are recognized in the chapters of this work: Globigerinitoidea and Guembelitriodea. Their placement relative to other superfamilies of foraminifera is not yet known.
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Atlas of Oligocene Planktonic Foraminifera
The taxonomy, biostratigraphy, distribution, paleoecology and phylogenetic systematics of Oligocene planktonic foraminifera are treated in an illustrated atlas format. One hundred and twenty-eight species are recognized, including three species of Catapsydrax, eight species of Globorotaloides, two species of Protentelloides, twelve species of Paragloborotalia, two species of Parasubbotina, three species of Globigerina, eight species of Globigerinella, two species of Quiltyella Coxall and Spezzaferri n. gen., four species of Ciperoella Olsson and Hemleben n. gen., fifteen species of Globoturborotalita, seven species of Globigerinoides, seven species of Trilobatus, nine species of Subbotina, sixteen species of Dentoglobigerina, one species of Globoquadrina, two species of Turborotalita, three species of Acarinina, two species of Pseudohastigerina, two species of Turborotalia, two species of Dipsidripella, two species of Globigerinita, four species of Tenuitella, four species of Chiloguembelina, two species of Jenkinsina, two species of Cassigerinella, and four species of Streptochilus.
We name fourteen new species: Chiloguembelina adriatica Premec Fucek, Hernitz Kucenjak and Huber n. sp., Chiloguembelina andreae Premec Fucek, Hernitz Kucenjak and Huber n. sp., Dentoglobigerina eotripartita Pearson, Wade and Olsson n. sp., Globigerina archaeobulloides Hemleben and Olsson n. sp., Globigerinella roeglina Spezzaferri and Coxall n. sp., Globigerinoides neoparawoodi Spezzaferri n. sp., Globigerinoides joli Spezzaferri n. sp., Globoturborotalita eolabiacrassata Spezzaferri and Coxall n. sp., Globoturborotalita paracancellata Olsson and Hemleben n. sp., Globoturborotalita pseudopraebulloides Olsson and Hemleben n. sp., Globorotaloides atlanticus Spezzaferri and Coxall n. sp., Subbotina projecta Olsson, Pearson, and Wade n. sp., Streptochilus tasmanensis Smart and Thomas n. sp. and Trilobatus altospiralis Spezzaferri n. sp. The following new genera are named: Ciperoella Olsson and Hemleben n. gen. and Quiltyella Coxall and Spezzaferri, n. gen.
Over 2000 scanning electron micrographs images, including the type specimens of more than 60 species are illustrated for the first time, providing fresh comprehension of the shell architecture and wall texture, particularly for species that were poorly illustrated when first described. The biostratigraphic occurrences and phylogenetic relationships of all species of Oligocene planktonic foraminifera are reviewed. Analysis of wall textures, based on well-preserved material (much of which is illustrated for the first time) provides the basis for the higher taxonomy. Accordingly, Oligocene normal perforate planktonic foraminifera are divided into the Families Globigerinidae, Truncorotaloididae, and Globanomalinidae. Oligocene microperforate species, are placed in the Families Globigerinitidae, Chiloguembelinidae, Guembelitriidae, and Cassigerinellidae.