pforams@mikrotax - Orcadia riedeli pforams@mikrotax - Orcadia riedeli

Orcadia riedeli

Classification: pf_cenozoic -> Hastigerinidae -> Orcadia -> Orcadia riedeli
Sister taxa: O. riedeli, O. sp.


Citation: Orcadia riedeli (Rögl & Bolli, 1973)
Rank: species
Basionym: Hastigerinella riedeli Rögl & Bolli, 1973

Catalog entries: Hastigerinella riedeli

Type images:

Distinguishing features:
Parent taxon (Orcadia): Spine bases at chamber tips:
This taxon: monospecific

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.


Test very small, low trochospiral to slightly streptospiral, equatorial periphery distinctly lobulate; axial periphery broadly rounded; chambers subglobular, 5 in the final whorl, increasing slowly in size as added, final chamber slightly bent over the umbilicus; suture distinct, nearly radial, depressed; surface smooth , delicate with very fine, widely spaced perforations and triradial spines , which are concentrated on the distal ends of chambers; aperture interiomarginal, umbilical, rather a low arch, bordered by a narrow but distinct lip. [Kennett & Srinivasan 1983]


Character matrix
test outline:Stellatechamber arrangement:Trochospiraledge view:Concavo-convexaperture:Umbilical
sp chamber shape:Elongatecoiling axis:Lowperiphery:N/Aaperture border:Thin lip
umb chbr shape:Elongateumbilicus:Narrowperiph margin shape:Moderately roundedaccessory apertures:None
spiral sutures:Moderately depressedumb depth:Shallowwall texture:Smoothshell porosity:Microperforate: <1µm
umbilical or test sutures:Moderately depressedfinal-whorl chambers:5.0-5.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology

Geographic distribution

A conspicuous small species, occurring in temperate to subpolar waters of both hemispheres [Brummer & Kucera 2022]

Phylogenetic relations
The ancestry of Hs. riedeli is uncertain (Text Fig. 26). The surface ultrastructure suggests that it most closely resembles Hastigerina pelagica. [Kennett & Srinivasan 1983]

Most likely ancestor: Hastigerina pelagica - at confidence level 1 (out of 5). Data source: Kennett & Srinivasan 1983, fig. 26.

Biostratigraphic distribution

Geological Range:
Last occurrence (top): Extant. Data source: present in the plankton (SCOR WG138)
First occurrence (base): within N22 zone (0.00-1.93Ma, base in Gelasian stage). Data source: Kennett & Srinivasan 1983 (as Hastigerinopsis reideli)

Plot of occurrence data:

Primary source for this page: Kennett & Srinivasan 1983, p.244


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

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

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

Poore, R. Z. (1979). Oligocene through quarternary planktonic foraminiferal biostratigraphy of the North Atlantic: DSDP LEG 49. Initial Reports of the Deep Sea Drilling Project. 49: 447-517. gs

Rögl, F. & Bolli, H. M. (1973). Holocene to Pleistocene planktonik foraminifera of LEG 15, site 147 (Cariaco Basin (Trench), Caribbean Sea) and their climatic interpretation. Initial Reports of the Deep Sea Drilling Project. 15: 553-579. gs V O

Saito, T. (1976). Geologic significance of coiling direction in the planktonic foraminifera Pulleniatina. Geology. 4(5): 305-309. gs

Saito, T., Thompson, P. R. & Breger, D. (1981). Systematic Index of Recent and Pleistocene Planktonic Foraminifera. University of Tokyo Press, Tokyo. 1-190. gs


Orcadia riedeli compiled by the pforams@mikrotax project team viewed: 2-4-2023

Taxon Search:
Advanced Search
AphiaID: 418109 Nomenclatural data on WoRMS
Short stables page link: Go to to create a permanent copy of this page - citation notes

Comments (0)

No comments yet on this page. Please do add comments if you spot any problems, or have information to share

Add Comment

* Required information
Captcha Image
Powered by Commentics