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: 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.


Morphology: 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]

Size: <150µm

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: Tropical to warm subtropical. [Kennett & Srinivasan 1983]

In modern oceans a rare, cold water, species [SCOR WG138]

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


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: 12-4-2021

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Short stable page link: https://mikrotax.org/pforams/index.php?id=104186 Go to Archive.is to create a permanent copy of this page - citation notes

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