pforams@mikrotax - Planohedbergella ultramicra pforams@mikrotax - Planohedbergella ultramicra

Planohedbergella ultramicra


Classification: pf_mesozoic -> Globigerinelloididae -> Planohedbergella -> Planohedbergella ultramicra
Sister taxa: P. aspera, P. circularis, P. escheri, P. impensa, P. messinae, P. multispina, P. prairiehillensis, P. subcarinata, P. ultramicra, P. yaucoensis

Taxonomy

Citation: Planohedbergella ultramicra (Subbotina, 1949)
taxonomic rank: species
Basionym: Globigerinella ultramicra Subbotina, 1949
Synonyms:

Type images:

Original description: Test the smallest of all representatives of Globigerinella known to date. It is flat, rounded, and bilaterally symmetrical, but not involute. There are two whorls. Diameter of the first whorl disproportionately small in comparison with the diameter of the second whorl. In specimens with both sides well preserved, the chambers of the first whorl are visible in the median, depressed portion. Peripheral border rounded, lobate. Chambers almost spherical, slightly compressed laterally, very imperceptibly differing in size from one another. In the final whorl there are six to eight chambers. Sutures simple, weakly curved, almost straight, depressed. Aperture typical of the genus. Wall smooth.


Entries in the Catalog of original descriptions: Globigerinella ultramicra


Emended description:

Test the smallest of all representatives of Globigerinella known to date. It is flat, rounded, and bilaterally symmetrical-, but not involute. There are two whorls. Diameter of the first whorl disproportionately small in comparison with the diameter of the second whorl. In specimens with both sides well preserved, the chambers of the first whorl are visible in the median, depressed portion. Peripheral border rounded, lobate. Chambers almost spherical, slightly compressed laterally, very imperceptibly differing in size from one another. In the final whorl there are six to eight chambers. Sutures simple, weakly curved, almost straight, depressed. Aperture typical of the genus. Wall smooth. [copied from Chronos database]

Character matrix
test outline:Circularchamber arrangement:Planispiraledge view:Hourglassaperture:Equatorial
sp chamber shape:Inflatedcoiling axis:N/Aperiphery:N/Aaperture border:Thin lip
umb chbr shape:Inflatedumbilicus:Wideperiph margin shape:Narrowly roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Shallowwall texture:Finely pustuloseshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:6-8 N.B. These characters are used for advanced search. N/A - not applicable

Geological Range:
Last occurrence (top): within C. plummerae zone (75.91-79.33Ma, top in Campanian stage). Data source: Huber et al 2022
First occurrence (base): within P. appenninica zone (100.50-101.92Ma, base in Albian stage). Data source: Huber et al 2022

Plot of range and occurrence data:

References:

Falzoni, F., Petrizzo, M. R., Jenkyns, H. C., Gale, A. S. & Tsikos, H. (2016). Planktonic foraminiferal biostratigraphy and assemblage composition across the Cenomanian–Turonian boundary interval at Clot Chevalier (Vocontian Basin, SE France). Cretaceous Research. 59: 69-97. gs

Huber, B. T., Petrizzo, M. M. & Falzoni, F. (2022b). Taxonomy and phylogeny of Albian–Maastrichtian planispiral planktonic foraminifera traditionally assigned to Globigerinelloides. Micropaleontology. 68(2): 117-183. gs

Subbotina, N. N. (1949). Микрофауна меловых отложений южного склона Кавказа [Microfauna from the Cretaceous of the southern slope of the Caucasus]. Trudy VNIGRI Mikrofauna USSR. 34: 5-36. gs

Missing or ambiguous references: ;


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Planohedbergella ultramicra compiled by the pforams@mikrotax project team viewed: 27-2-2024

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Short stable page link: https://mikrotax.org/pforams/index.php?id=110148 Go to Archive.is to create a permanent copy of this page - citation notes



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