Beella megastoma


Classification: pf_cenozoic -> Globigerinidae -> Beella -> Beella megastoma
Sister taxa: B. digitata, B. megastoma, B. praedigitata, B. sp.,

Taxonomy

Citation: Beella megastoma (Earland 1934)
Rank: species
Basionym: Globigerina megastoma
Taxonomic discussion: Kennett & Srinivasan (1983) considered G. megastoma to be  a junior synonym of G. bulloides, but used G. praedigitata in  similar sense. Holmes (1984) suggested that G. megastoma was the senior synyom of G. praedigitata. Most authors have only used one of the two species megastoma and praedigitata but both are included in Aze et al (2011)

Catalog entries: Globigerina megastoma

Type images:

Distinguishing features: Trochospiral becoming streptospiral, chambers rounded to digitate; wall irregularly 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: Trochospiral becoming streptospiral, chambers rounded to digitate

Aperture: Interiomarginal umbilical-extraumbilical wide open symmetrical arch bordered by a thin lip [Aze 2011, based on Holmes 1984]


Wall type: Spinose; Irregularly cancellate [Aze et al 2011]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Spiroconvexaperture:Umbilical-extraumbilical
sp chamber shape:Elongatecoiling axis:Low-moderateperiphery:N/Aaperture border:Thick lip
umb chbr shape:Globularumbilicus:Wideperiph margin shape:Broadly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Deepwall texture:Cancellateshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Strongly 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: Low to middle latitudes [Aze et al. 2011, based on Holmes (1984)]

[SCOR WG138]


Isotope paleobiology: Aze et al. 2011 ecogroup 4 - Open ocean sub-thermocline. Based on very light ∂13C and very heavy ∂18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Most likely ancestor: Beella digitata - at confidence level 2 (out of 5). Data source: Aze et al. 2011.

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant Data source: Not recognised by WG138 but recorded as extant by Aze et al. 2011
First occurrence (base): within PT1a subzone (0.61-1.88Ma, base in Gelasian stage). Data source: Aze et al. 2011

Plot of occurrence data:

References:

Aze, T. et al. (2011). A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data. Biological Reviews. 86: 900-927. gs :: ::

Earland, A. (1934). Foraminifera. Part III. The Falklands sector of the Antarctic (excluding South Georgia). Discovery Reports. 10: 1-208. gs :: ::

Holmes, N. A. (1984). An emendation of the genera Beella Banner and Blow, 1960, and Turborotalita Blow and Banner, 1962; with notes on Orcadia Boltovskoy and Watanabe, 1982. Journal of Foraminiferal Research. 14(2): 101-110. gs :: ::

Kennett, J. P. & Srinivasan, M. S. (1983). Neogene Planktonic Foraminifera. Hutchinson Ross Publishing Co., Stroudsburg, Pennsylvania. 1-265. gs :: ::


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Beella megastoma compiled by the pforams@mikrotax project team viewed: 14-7-2020

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Short stable page link: http://mikrotax.org/pforams/index.php?id=104003 Go to Archive.is to create a permanent copy of this page - citation notes



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