Igorina albeari


Classification: pf_cenozoic -> Truncorotaloididae -> Igorina -> Igorina albeari
Sister taxa: I. tadjikistanensis, I. albeari, I. pusilla, I. sp.,

Taxonomy

Citation: Igorina albeari (Cushman and Bermudez 1949)
Rank: Species
Basionym: Globorotalia albeari
Synonyms:
Taxonomic discussion: Comparison of the type specimens (Plate 16: Figures 1-6) of Globorotalia albeari Cushman and Renz, 1946, and G. pusilla laevigata Bolli, 1957a, by Blow (1979) and Berggren (I960, 1965, 1968, 1969a, 1977) have confirmed the suspicions previously raised by Postuma (1971) of the synonymy of these two forms. Most notable is the presence of a distinct peripheral carina in this taxon that was not shown in the holotype illustration by Cushman and Renz (1946) nor, surprisingly, in the refiguration of the holotype by Cifelli and Belford (1977). We have observed a wide range of variation in the degree of convexity of the spiral side in this taxon and have tried to convey this variation in Plate 56: Figures 1-16. The umbilical side is generally less convex than the spiral side, and the final chamber is often flattened and smoother (less pustulose) than the remainder of the test. [Olsson et al. 1999]

Catalog entries: Globorotalia albeari, Globorotalia pusilla laevigata

Type images:

Distinguishing features: Test moderately to strongly biconvex; sutures on spiral side strongly recurved yielding trapezoidal-shaped chambers; peripheral margin distinctly carinate, particularly on last chambers.

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: Moderately to strongly biconvex, essentially circular, cancellate, pustulose test with 6-8 chambers in final whorl; intercameral sutures on umbilical side radial to weakly recurved yielding triangular-shaped chambers; strongly recurved and exhibiting distinct limbation on the spiral side, particularly between the last 3-4 chambers, yielding trapezoidal-shaped chambers; peripheral margin distinctly carinate, particularly on last chambers of the final whorl; aperture a low interiomarginal, umbilical-extraumbilical arch extending towards, but to, the peripheral margin. [Olsson et al. 1999]

Character matrix

test outline:Subcircularchamber arrangement:Planispiraledge view:Equally biconvexaperture:Umbilical
sp chamber shape:Petaloidcoiling axis:N/Aperiphery:Single keelaperture border:Thin lip
umb chbr shape:Subtriangularumbilicus:Narrowperiph margin shape:Narrowly roundedaccessory apertures:None
spiral sutures:Weakly depressedumb depth:Deepwall texture:Coarsely pustuloseshell porosity:Macroperforate: >2.5µm
umbilical or test sutures:Weakly depressedfinal-whorl chambers:6.0-8.0 N.B. These characters are used for advanced search. N/A - not applicable

Biogeography and Palaeobiology


Geographic distribution: Igorina albeari is predominantly tropical to subtropical, low latitude, in distribution. It has not been recorded from high southern latitudes at appropriate stratigraphic levels (Stott and Kennett, 1990), although Huber (1991b) recorded/illustrated a form (pl. 3: figs. 18, 19) similar to albeari (as pusilla) from a biostratigraphic level (Zone AP5 near the Paleocene/Eocene boundary) in ODP Hole 738C (Kerguelen Plateau, southern Indian Ocean). From our experience with Russian literature and the comparative material in the collection at WHOI, it would appear that this taxon has not been recorded or is not present in the Caucasus-Crimean Paleocene (Figure 26). [Olsson et al. 1999]
Aze et al. 2011 summary: Tropical to sub-tropical; based on Olsson et al. (1999)

Isotope paleobiology: Igorina albeari has ∂13C more negative than Acarinina and Morozovella but more positive than Subbotina and Globanomalina. The S180 of I. albeari is more negative than Subbotina and Globanomalina but is more positive than Morozovella (Berggren and Norris, 1997). [Olsson et al. 1999]
Aze et al. 2011 ecogroup 1 - Open ocean mixed-layer tropical/subtropical, with symbionts. Based on very heavy δ13C and relatively light δ18O. Sources cited by Aze et al. 2011 (appendix S3): Berggren & Norris (1997)

Phylogenetic relations: Igorina albeari is derived from /. pusilla by the development of compressed chambers and a keel
on one or more chambers in the final whorl. [Olsson et al. 1999]

Most likely ancestor: Igorina pusilla - at confidence level 4 (out of 5). Data source: Olsson et al. (1999), f5a.

Biostratigraphic distribution

Geological Range:
Notes: Zone P3a/P3b boundary to Zone P4. [Olsson et al. 1999]
The FAD of Igorina albeari marks the base of zone P3b / top of P3a (Wade et al. 2011)
Last occurrence (top): at top of P4c subzone (100% up, 57.1Ma, in Thanetian stage). Data source: Olsson et al. (1999), f5a
First occurrence (base): at base of P3b subzone (0% up, 61.3Ma, in Selandian stage). Data source: zonal marker (Wade et al. 2011)

Plot of occurrence data:

Primary source for this page: Olsson et al. 1999 - Atlas of Paleocene Planktonic Foraminifera, p. 69

References:

Blow, W. H. (1979). The Cainozoic Globigerinida: A study of the morphology, taxonomy, evolutionary relationships and stratigraphical distribution of some Globigerinida (mainly Globigerinacea). E. J. Brill, Leiden. 2: 1-1413. gs

Bolli, H. M. & Cita, M. B. (1960). Globigerine e Globorotalie del Paleocene di Paderno d'Adda (Italia). Rivista Italiana di Paleontologia e Stratigrafia. LXVI(3): 1-42. gs

Bolli, H. M. (1957d). The genera Globigerina and Globorotalia in the Paleocene-Lower Eocene Lizard Springs Formation of Trinidad. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 61-82. gs

Cifelli, R. & Belford, D. J. (1977). The Types of Several Species of Tertiary Planktonic Foraminifera in the Collections of the U.S. National Museum of Natural History. Journal of Foraminiferal Research. 7: 100-105. gs

Cushman, J. A. & Bermudez, P. J. (1949). Some Cuban species of Globorotalia. Contributions from the Cushman Laboratory for Foraminiferal Research. 25: 26-45. gs

Hillebrandt, A. , von (1962). Das Paleozän und seine Foraminiferenfauna im Becken von Reichenhall und Salzburg. Abhandlungen Bayerischen Akademie der Wissenschaften, Mathematisch-Naturwissenschaftliche Klasse, Neue Folge. 108: 1-182. gs

Loeblich, A. R. & Tappan, H. (1957b). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In, Loeblich, A. R. , Jr. , Tappan, H. , Beckmann, J. P. , Bolli, H. M. , Montanaro Gallitelli, E. & Troelsen, J. C. (eds) Studies in Foraminifera. U.S. National Museum Bulletin. 215: 173-198. gs

McGowran, B. J. (1965). Two Paleocene foraminiferal faunas from the Wangerrip Group, Pebble Point Coastal Section, Western Australia. Proceedings of the Royal Society of Victoria. 79: 9-74. 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

Postuma, J. A. (1971). Manual of planktonic foraminifera. Elsevier for Shell Group, The Hague. 1-406. gs

Soldan, D. M., Petrizzo, M. R., Silva, I. P. & Cau, A. (2011). Phylogenetic relationships and evolutionary history of the Paleogene genus through parsimony analysis. Journal of Foraminiferal Research. 41: 260-284. gs

Wade, B. S., Pearson, P. N., Berggren, W. A. & Pälike, H. (2011). Review and revision of Cenozoic tropical planktonic foraminiferal biostratigraphy and calibration to the geomagnetic polarity and astronomical time scale. Earth-Science Reviews. 104: 111-142. gs


logo

Igorina albeari compiled by the pforams@mikrotax project team viewed: 15-11-2019

Taxon Search:
Advanced Search

Short stable page link: http://mikrotax.org/pforams/index.php?id=100171 Go to Archive.is to create a permanent copy of this page - citation notes



Comments (0)

No comments yet. Be the first!

Add Comment

* Required information
1000
Captcha Image
Powered by Commentics