pforams@mikrotax - Orcadia pforams@mikrotax - Orcadia


Classification: pf_cenozoic -> Hastigerinidae -> Orcadia
Sister taxa: Hastigerina, Hastigerinella ⟩⟨ Orcadia
Daughter taxa (time control age-window is: 0-800Ma)
Orcadia riedeli
Orcadia sp.
Specimens which cannot be assigned to established species


Citation: Orcadia Boltovskoy & Watanabe, 1982
taxonomic rank: genus
Type species: Hastigerinella riedeli

Catalog entries: Orcadia

Distinguishing features:
Parent taxon (Hastigerinidae): monolamellar, thick spines, thin shell
This taxon: Spine bases at chamber tips:

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.


Biogeography and Palaeobiology

Phylogenetic relations

The phylogenetic position of this monotypic genus re- mains enigmatic, requiring retention of the genus name (Holmes, 1984; Brummer et al., 1988c). It is here provi- sionally placed among the Hastigerinidae, awaiting revision based on molecular data. [Brummer & Kucera 2022]

Most likely ancestor: Hastigerina - at confidence level 1 (out of 5). Data source: Kennett & Srinivasan 1983 - based on tentative suggestion that O. riedeli evolved from H. pelagica .

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source: Total of ranges of the species in this database
First occurrence (base): within N22 zone (0.00-1.93Ma, base in Gelasian stage). Data source: Total of ranges of species in this database

Plot of occurrence data:


Boltovskoy, E. & Watanabe, S. (1982). Orcadia, nuevo genero de Foraminiferos planctonicos Antarticos. Revista Española de Micropaleontología. 14: 5-11. gs

Brummer, G-J. A. & Kucera, M. (2022). Taxonomic review of living planktonic foraminifera. Journal of Micropalaeontology. 41: 29-74. gs

Brummer, G. J. A., Troelstra, S. R., Kroon, D. & Ganssen, G. M. (1988). Ontogeny, distribution and geologic record of the extant planktonic foraminifer Orcadia riedeli (Rögl & Bolli, 1973). In, Brummer, G. J. A. & Kroon, D. (eds) Planktonic foraminifers as tracers of ocean-climate history. Free University Press, Amsterdam 149-162. 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


Orcadia compiled by the pforams@mikrotax project team viewed: 25-6-2024

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