Chapter 5: TAXONOMY, BIOSTRATIGRAPHY, AND PHYLOGENY OF OLIGOCENE AND EARLY MIOCENE PARAGLOBOROTALIA AND PARASUBBOTINA
Published:January 31, 2018
R. Mark Leckie, Bridget S. Wade, Paul N. Pearson, Andrew J. Fraass, David J. King, Richard K. Olsson, Isabella Premoli Silva, Silvia Spezzaferri, William A. Berggren, 2018. "TAXONOMY, BIOSTRATIGRAPHY, AND PHYLOGENY OF OLIGOCENE AND EARLY MIOCENE PARAGLOBOROTALIA AND PARASUBBOTINA", Atlas of Oligocene Planktonic Foraminifera, Bridget S. Wade, Richard K. Olsson, Paul N. Pearson, Brian T. Huber, William A. Berggren
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The taxonomy, phylogeny, and biostratigraphy of Oligocene and early Miocene Paragloborotalia and Parasubbotina are reviewed. The two genera are closely related; Paragloborotalia was derived from Parasubbotina in the early Eocene. Parasubbotina was more diverse during the middle Eocene, while Paragloborotalia experienced considerable diversification during the mid-Oligocene and in the latest Oligocene-earliest Miocene. A significant finding has been the synonymization of Globorotalia (Tuborotalia) mendacis Blow, and Turborotalia primitiva Brönnimann and Resig with Globorotalia birnageae Blow. The following species from the time interval of interest are regarded as valid: Paragloborotalia acrostoma (Wezel), Paragloborotalia birnageae (Blow), Paragloborotalia continuosa (Blow), Paragloborotalia incognita (Walters) Paragloborotalia kugleri (Bolli), Paragloborotalia mayeri (Cushman and Ellisor), Paragloborotalia nana (Bolli), Paragloborotalia opima (Bolli), Paragloborotalia pseudocontinuosa (Jenkins), Paragloborotalia pseudokugleri (Blow), Paragloborotalia semivera (Hornibrook), Paragloborotalia siakensis (LeRoy), Parasubbotina hagni (Gohrbandt), and Parasubbotina varianta (Subbotina).
Paragloborotalia is a long-lived group of planktonic foraminifera that spanned the early Eocene to late Miocene and provided the root stock for the evolution of multiple smooth, nonspinose, and keeled globorotaliid lineages during the Neogene. The early Oligocene forms of Paragloborotalia (nana, opima, siakensis, pseudocontinuosa) have 4 or 5 globular chambers in the final whorl with radial spiral sutures and a broadly rounded periphery. A trend from radial to curved spiral sutures is observed in late Oligocene and earliest Miocene lineages. Most species of Paragloborotalia had wide distributions, but some were more common in tropical to warm subtropical waters (e.g., siakensis, kugleri) and were especially dominant in the equatorial Pacific divergence zone (e.g., nana, opima, and pseudocontinuosa) analogous to modern tropical upwelling Neogloboquadrina. Other species thrived in cool subtropical and temperate waters (e.g., acrostoma, incognita).
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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.