Globoturborotalita bassriverensis


Classification: pf_cenozoic -> Globigerinidae -> Globoturborotalita -> Globoturborotalita bassriverensis
Sister taxa: G. tenella, G. rubescens, G. decoraperta, G. apertura, G. connecta, G. druryi, G. nepenthes, G. woodi, G. cancellata, G. occlusa, G. paracancellata, G. pseudopraebulloides, G. barbula, G. bassriverensis, G. brazieri, G. eolabiacrassata, G. euapertura, G. gnaucki, G. labiacrassata, G. martini, G. ouachitaensis, G. sp.,

Taxonomy

Citation: Globoturborotalita bassriverensis Olsson & Hemleben, in Olsson et al. 2006
Rank: Species
Basionym: Globoturborotalita bassriverensis Globigerinatheka
Synonyms:
Taxonomic discussion: Globoturborotalita bassriverensis is described from an exceptionally well-preserved assemblage of planktonic foraminifera from a Zone E1 section in the Bass River Borehole, ODP 174AX, New Jersey Coastal Plain. The assemblage from which this species is described is associated with the carbon isotope excursion (CIE) and the Paleocene-Eocene Thermal Maximum (PETM). In addition, the excursion taxa (Kelly and others, 1996), Acarinina africana, A. sibaiyaensis, and Morozovella allisonensis also occur in this E1 assemblage. The bassriverensis morphology has not been observed in the Paleocene (Olsson and others, 1999). Thus, it appears that the origin of Globoturborotalita is related to climate-induced changes in the structure of water masses during the PETM. The genus was apparently derived from Subbotina because of its symmetrical sacculifer-type, spinose wall texture and umbilically directed aperture. Specimens are quite common but have probably been overlooked because of their small size. [Olsson et al. 2006]

This species was described from lower Eocene Zone E1 and is more typical of the Eocene than the Oligocene (see Olsson and others, 2006 for the complete description, synonymy and discussion). Initially reported as ranging to Zone E10 (Olsson and others, 2006), it is here included for completeness because new observations have extended its range to the lower Oligocene Zone AO1 (Pl. 8.1, Figs. 11-14). Four specimens that were originally figured as  G. bassriverensis by Olsson and others (2006) in plate 6.3, figs. 16-19, are here assigned to Globoturborotalita eolabiacrassata Spezzaferri and Coxall n. sp. (Pl. 8.5) based on their more compact profile and possession of a thickened rim bordering the aperture. The Globoturborotalita bassriverensis diagnosis, therefore, is restricted to forms with a more enclosing globular final chamber and a thin apertural lip. [Spezzaferri et al. 2018]

Catalog entries: Globoturborotalita bassriverensis

Type images:

Distinguishing features: Test small, 4 globular, slightly embracing chambers in final whorl. Aperture umbilical with prominent lip, wall cancellate.

NB These concise distinguishing features statements are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus.
They are being edited as the site is developed and comments on them are especially welcome.

Description


Diagnostic characters: The species is characterized by its small size, 4 globular, slightly embracing chambers in the final whorl, umbilical aperture, and cancellate wall texture. It is distinguished from G. ouachitaensis, which it most closely resembles, by its thicker, more prominent lip which it shares with its ancestral genus Subbotina. [Olsson et al. 2006]

Wall type: Cancellate, normal perforate, spinose, sacculifer-type wall structure.

Test morphology: Test moderately low trochospiral, globular, lobulate in outline, chambers globular; in spiral view 4 globular, slightly embracing chambers in ultimate whorl, increasing moderately in size, sutures depressed, straight, last 4 chambers make up about 1/2 of the test size; in umbilical view 4 globular, slightly embracing chambers, increasing moderately in size, sutures depressed, straight, umbilicus small, open, enclosed by surrounding chambers, aperture umbilical, a rounded arch, bordered by a narrow lip that is thickened in some specimens; in edge view chambers globular in shape, slightly embracing, initial spire of chambers slightly elevated.

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Concavo-convexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Moderateperiphery:N/Aaperture border:Thick lip
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:4.0-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Distributed in mid- to low latitudes. [Olsson et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Olsson et al. (2006a)

Isotope paleobiology: Recorded (as ‘small globigeriniforms’) by Pearson and others (2001) from the middle Eocene of Tanzania with relatively negative ∂18O indicating a shallow water habitat. [Olsson et al. 2006]
Aze et al. 2011 ecogroup 2 - Open ocean mixed-layer tropical/subtropical, without symbionts. Based on δ13C lighter than species with symbionts; also with relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): Pearson et al. (2001a)

Phylogenetic relations: Globoturborotalita bassriverensis is the first species in a generic line that extends to the Recent. The probable ancestor is Subbotina hornibrooki. [Olsson et al. 2006]

Most likely ancestor: Subbotina hornibrooki - at confidence level 3 (out of 5). Data source: Olsson et al. 2006, f5.1.
Likely descendants: Globoturborotalita cancellata; Globoturborotalita eolabiacrassata; Globoturborotalita martini; Globoturborotalita ouachitaensis; Turborotalita carcoselleensis;

Biostratigraphic distribution

Geological Range:
Notes: Zone E1 to Zone E10? [Olsson et al. 2006] Initially reported as ranging to Zone E10 (Olsson et al., 2006), new observations have extended its range to the lower Oligocene Zone AO1 [Spezzaferri et al 2018]
Last occurrence (top): within O1 zone (32.10-33.90Ma, top in Rupelian stage). Data source: Spezzaferri et al 2018;
First occurrence (base): within E1 zone (55.81-55.96Ma, base in Ypresian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.8 p.225; Olsson et al. 2006 - Eocene Atlas, chap. 6, p. 117;

References:

Kelly, D. C., Bralower, T. J., Zachos, J. C. & Premoli Silva, I. T. , E. (1996). Rapid diversification of planktonic foramiifer in the tropical Pacific (ODP Site 865) during the late Paleocene thermal maximum. Geology. 24: 423-426. gs

Olsson, R. K., Hemleben, C., Berggren, W. A. & Huber, B. T. (1999). Atlas of Paleocene Planktonic Foraminifera. Smithsonian Institution Press, Washington, DC. 1-252. gs

Olsson, R. K., Hemleben, C., Huber, B. T. & Berggren, W. A. (2006b). Taxonomy, biostratigraphy, and phylogeny of Eocene Globigerina, Globoturborotalita, Subbotina, and Turborotalita. In, Pearson, P. N. , Olsson, R. K. , Hemleben, C. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Eocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 41(Chap 6): 111-168. gs

Pearson, P. N. & Wade, B. S. (2015). Systematic taxonomy of exceptionally well-preserved planktonic foraminifera from the Eocene/Oligocene boundary of Tanzania. Cushman Foundation for Foraminiferal Research, Special Publication. 45: 1-85. gs

Spezzaferri, S., Olsson, R. K., Hemleben, C., Wade, B. S. & Coxall, H. K. (2018c). Taxonomy, biostratigraphy, and phylogeny of Oligocene and Lower Miocene Globoturborotalita. In, Wade, B. S. , Olsson, R. K. , Pearson, P. N. , Huber, B. T. & Berggren, W. A. (eds) Atlas of Oligocene Planktonic Foraminifera. Cushman Foundation for Foraminiferal Research, Special Publication. 46(Chap 8): 231-268. gs


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Globoturborotalita bassriverensis compiled by the pforams@mikrotax project team viewed: 14-11-2019

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