Globoturborotalita barbula


Classification: pf_cenozoic -> Globigerinidae -> Globoturborotalita -> Globoturborotalita barbula
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 barbula Pearson & Wade 2015
Rank: Species
Synonyms:

Globoturborotalita barbula Pearson and Wade 2015:10-11, figs. 6, 1a-5b; 7,1a-5; 8, 1a-8 [upper Eocene Zone E15/E16, TDP Site 17, Tanzania].

[Spezzaferri et al. 2018]
Taxonomic discussion:

This species is a common component in assemblages at the Eocene/Oligocene transition in Tanzania and Java (Pearson and Wade, 2015). Due to its small size it has probably been overlooked in previous studies. Some specimens illustrated in Olsson and others (2006, pl. 6.10, figs. 13, 15) as Subbotina gortanii are very similar in morphology to G. barbula, but the presence of barbules is not proven. Wade and Pearson (2008) assigned these specimens to G. ouachitaensis. However, comparison with the holotype of G. ouachitaensis illustrated in Pl. 8.11, Figs. 1-3, disproves this hypothesis. We retain here G. ouachitaensis as the most probable ancestor of G. barbula. [Spezzaferri et al. 2018]

Catalog entries: Globoturborotalita barbula

Type images:

Distinguishing features: Similar to G. ouachitaensis but with barbules, (conical spikes) in the sutural regions

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 peculiar distinguishing feature of this species is the high density of minute, highly conical, spikes that are concentrated in the sutural regions of the test on both the umbilical and spiral sides (Pl. 8.1, Figs. 4 and 7).

[Spezzaferri et al. 2018]

Wall type: Normal perforate, cancellate, spinose, ruber/sacculifer-type wall texture with an average of 18 pores/50 μm 2 test surface area. Minute spikes “barbules” concentrated in sutural areas. [Spezzaferri et al. 2018]

Test morphology: Test moderately to very high trochospiral, petaloid in outline, chambers globular and inflated; in spiral view usually 3 ½ (occasionally 4), slightly embracing in the final whorl, increasing moderately in size; in umbilical view 3 ½ (occasionally 4) globular, slightly embracing chambers, increasing moderately in size, the last chamber is usually kummerform, sutures depressed, straight or slightly arched on both sides, umbilicus large and open, aperture umbilical, a rounded arch, bordered by an imperforate, thickened rim; in edge view chambers globular in shape, slightly embracing. A detailed description is given in Pearson and Wade (2015). [Spezzaferri et al. 2018]

Size: Maximum diameter of holotype 0.23 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:Umbilical
sp chamber shape:Globularcoiling axis:Moderate-highperiphery:N/Aaperture border:Thin 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:3.5-4.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Very common in Tanzania, its presence has been documented also in Java. [Spezzaferri et al. 2018]

Isotope paleobiology: The data from Pearson and Wade (2015) indicate that this species calcified in warm surface water habitat. [Spezzaferri et al. 2018]

Phylogenetic relations: Globoturborotalita barbula probably evolved from G. ouachitaensis. [Spezzaferri et al. 2018]

Similar species: Subbotina gortanii is typically much larger with more closely appressed and embracing chambers

Most likely ancestor: Globoturborotalita ouachitaensis - at confidence level 4 (out of 5). Data source: Pearson & Wade (2015), p11.

Biostratigraphic distribution

Geological Range:
Notes: This species has a short stratigraphic range from the uppermost Eocene (Zone E15/E16) to the lowermost Oligocene (Zone O1). [Spezzaferri et al. 2018]
Last occurrence (top): within O1 zone (32.10-33.90Ma, top in Rupelian stage). Data source: Pearson & Wade (2015)
First occurrence (base): within E15 zone (34.68-35.89Ma, base in Priabonian stage). Data source: Pearson & Wade (2015)

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.8 p.224;

References:

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

Wade, B. S. & Pearson, P. N. (2008). Planktonic foraminiferal turnover, diversity fluctuations and geochemical signals across the Eocene/Oligocene boundary in Tanzania. Marine Micropaleontology. 68: 244-255. gs


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

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