Muricohedbergella holmdelensis


Classification: pf_cenozoic -> Globanomalinidae -> Muricohedbergella -> Muricohedbergella holmdelensis
Sister taxa: M. holmdelensis, M. monmouthensis, M. sp.,

Taxonomy

Citation: Muricohedbergella holmdelensis (Olsson 1964)
Rank: Species
Basionym: Hedbergella holmdelensis Olsson 1964
Synonyms:
Taxonomic discussion: Hedbergella holmdelensis is the ancestral species of the genus Globanomalina that first appears in Zone P0 of the basal Danian. Morphologically, H. holmdelensis is very similar to the first species of Globanomalina, G. archeocompressa. The key morphologic characters that phylogenetically link the two species are the small, compressed, smooth-walled test, the imperforate axial periphery, and the umbilical-extraumbilical aperture with its narrow lip. Hedbergella holmdelensis retains two typical hedbergellid characters: the numerous, spherical-shaped chambers in the inner whorl, which is an adult character of the majority of hedbergellid species in the Cretaceous, and the pustulose surface of the test, which is distributed rather uniformly over the chambers, in contrast to the more restricted occurrence of pustules in Paleogene species of Globanomalina. Pustule growth, particularly in the umbilical area, is related to gametogenetic calcification in smooth-walled species in the Cenozoic. Pustule growth in Hedbergella is largely unexplored, and its relationship to gametogenesis is unknown. Nevertheless, the difference in its distribution on the test suggests a different biological function for this genus than for Globanomalina. Globanomalina, however, is placed in the Hedbergellidae to reflect its
phylogenetic linkage with this important Cretaceous group of planktonic foraminifera. [Olsson et al. 1999]

Reombinedas Muricohedbergella homldelenesis by Huber & Leckie 2011

Catalog entries: Hedbergella holmdelensis

Type images:

Distinguishing features: Final whorl chambers ovate, elongated, compressed; test almost planispiral.

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 is characterized by the small, nearly planispiral test with 5, occasionally 6 chambers in the ultimate whorl. Six to seven chambers make up the penultimate whorl. The ovate, elongated, compressed chambers are typical of the species. The axial periphery is imperforate for the most part, being only sparsely penetrated by pores. The wall surface is smooth but is lightly covered by small pustules. The aperture, a high arch that extends from the umbilicus to the axial periphery, is bordered by a thin, narrow, uniformly wide lip. [Olsson et al. 1999]

Character matrix

test outline:Lobatechamber arrangement:Trochospiraledge view:Equally biconvexaperture:Extraumbilical-peripheral
sp chamber shape:Inflatedcoiling axis:Very lowperiphery:N/Aaperture border:Thick lip
umb chbr shape:Inflatedumbilicus:Wideperiph margin shape:Moderately roundedaccessory apertures:None
spiral sutures:Strongly depressedumb depth:Shallowwall texture:Finely pustuloseshell porosity:Finely Perforate: 1-2.5µm
umbilical or test sutures:Strongly depressedfinal-whorl chambers:5.0-6.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Apparently worldwide in the high to low latitudes. [Olsson et al. 1999]
Aze et al. 2011 summary: Cosmopolitan; based on Olsson et al. (1999)

Isotope paleobiology: No data available [Olsson et al. 1999]
Aze et al. 2011 ecogroup 3 - Open ocean thermocline. Based on light δ13C and relatively heavy δ18O. Sources cited by Aze et al. 2011 (appendix S3): this study

Phylogenetic relations: This species evolved in the Maastrichtian from a multichambered ancestor. [Olsson et al. 1999]

Biostratigraphic distribution

Geological Range:
Notes: Lower Maastrichtian to lower Zone P0. [Olsson et al. 1999]
Last occurrence (top): in lower part of P0 zone (40% up, 66Ma, in Danian stage). Data source: Olsson et al. 1999
First occurrence (base): within R. calcarata zone (75.71-76.18Ma, base in Campanian stage). Data source: Olsson et al. 1999

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 35

References:

Huber, B. T. & Leckie, R. M. (2011). Planktic foraminiferal species turnover across deep-sea Aptian/Albian boundary sections. Journal of Foraminiferal Research. 41: 53-95. 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 :: ::


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Muricohedbergella holmdelensis compiled by the pforams@mikrotax project team viewed: 2-7-2020

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