Globigerinella clavaticamerata


Classification: pf_cenozoic -> Globigerinidae -> Globigerinella -> Globigerinella clavaticamerata
Sister taxa: G. adamsi, G. calida, G. radians, G. siphonifera, G. clavaticamerata, G. molinae, G. navazuelensis, G. obesa, G. praesiphonifera, G. pseudobesa, G. roeglina, G. megaperta, G. wagneri, G. sp.,

Taxonomy

Citation: Globigerinella clavaticamerata (Jenkins, 1977)
Rank: species
Basionym: Protentella clavaticamerata Jenkins 1977
Synonyms:
Taxonomic discussion:

Jenkins (1977) described G. clavaticamerata as biumbilicate, thus, planispiral, however, the paratypes include also low trochospiral forms, i.e. with the spiral and umbilical sides distinguishable. Therefore, we include in this species also slightly trochospiral morphologies. The specimens identified as Protentella rohiensis and illustrated by Popescu and Brotea (1989, in pl. I, figs. 7-8 and 11-12) are referred to G. clavaticamerata because of a clear similarity in morphology. [Spezzaferri et al. 2018]

Catalog entries: Protentella clavaticamerata, Protentella rohiensis

Type images:

Distinguishing features: Near planispiral coiling and last 1 or 2 chambers radially elongate

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:

This species, described form the lower Miocene of a borehole in the English Channel, is distinguished from other Globigerinella species by having a radially elongated penultimate and/or last chambers. It differs from G. molinae by the more marked elongation of the last chamber. It differs from Protentella prolixa Lipps by the wall texture, which is finely cancellate in P. prolixa compared to bulloides-type in G. clavaticamerata. [Spezzaferri et al. 2018]


Wall type: Spinose; spines are supported by spine collars, which coalesce to form ridges. Pore concentrations range from around 80 pores/50 μm2 test surface area and pore diameters range from around 2 μm.


Test morphology: Test very low trochospiral, consisting of 2 whorls, sometimes becoming almost planispiral in the last whorl, ovate and slightly lobulate in outline, 4-6 chambers in the last whorl, increasing moderately in size, the last chamber, sometimes the last two chambers of the last whorl may be strongly radially elongated, sutures depressed, straight to slightly curved on both sides; aperture at the base of the last chamber interiomarginal a low arch bordered by a distinct lip. [Spezzaferri et al. 2018]

Size: Maximum diameter of the holotype 0.26 mm. [Spezzaferri et al. 2018]

Character matrix

test outline:Stellatechamber arrangement:Pseudoplanispiraledge view:Equally biconvexaperture:Extraumbilical-peripheral
sp chamber shape:Elongatecoiling axis:Very lowperiphery:N/Aaperture border:Thick lip
umb chbr shape:Elongateumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Strongly depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:4.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Cosmopolitan, documented in the English Channel, Atlantic, Indian and Pacific Oceans. It is however, never abundant. [Spezzaferri et al. 2018]

Isotope paleobiology: No data available. [Spezzaferri et al. 2018]

Phylogenetic relations: Globigerinella clavaticamerata possibly evolved from Globigerinella navazuelensis in the upper Oligocene Zone O5. [Spezzaferri et al. 2018]

Most likely ancestor: Globigerinella navazuelensis - at confidence level 1 (out of 5). Data source: Spezzaferri et al. 2018.

Biostratigraphic distribution

Geological Range:
Notes: Difficult to establish due to the sporadic occurrence. Existing constraints suggest it ranges from the upper Oligocene Zone O5 (Spezzaferri, 1994) to the Langhian in the middle Miocene (Jenkins, 1977). [Spezzaferri et al. 2018]
Last occurrence (top): within Langhian Stage (13.82-15.97Ma, top in Langhian stage). Data source: Spezzaferri et al. 2018
First occurrence (base): within O5 zone (26.93-28.09Ma, base in Chattian stage). Data source: Spezzaferri et al. 2018

Plot of occurrence data:

Primary source for this page: Spezzaferri et al. 2018 - Olig Atlas chap.6 p.190

References:

Jenkins, D. G. (1977). Lower Miocene planktonic forminfera from the a borehole in the English Channel. Micropaleontology. 23(3): 297-318. gs

Popescu, G. & Brotea, D. (1989). Genus Protentella (Foraminifera) in North Transylvania Oligcene. In, Petrescu, I. (ed.) The Oligocene from the Transylvanian Basin. Cluj-Napoca 255-260. gs

Spezzaferri, S. (1994). Planktonic foraminiferal biostratigraphy and taxonomy of the Oligocene and lower Miocene in the oceanic record. An overview. Palaeontographia Italica. 81: 1-187. gs

Spezzaferri, S., Coxall, H. K., Olsson, R. K. & Hemleben, C. (2018a). Taxonomy, biostratigraphy, and phylogeny of Oligocene Globigerina, Globigerinella, and Quiltyella n. gen. 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 6): 179-214. gs


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Globigerinella clavaticamerata compiled by the pforams@mikrotax project team viewed: 24-10-2019

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Short stable page link: http://mikrotax.org/pforams/index.php?id=104350 Go to Archive.is to create a permanent copy of this page - citation notes



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