Globigerinatheka korotkovi


Classification: pf_cenozoic -> spinose -> Globigerinidae -> Globigerinatheka -> Globigerinatheka korotkovi
Sister taxa: G. barri, G. curryi, G. euganea, G. index, G. korotkovi, G. kugleri, G. luterbacheri, G. mexicana, G. semiinvoluta, G. subconglobata, G. tropicalis,

Taxonomy

Citation: Globigerinatheka korotkovi (Keller 1946)
Rank: Species
Basionym: Globigerinoides korotkovi
Synonyms:
Taxonomic discussion: Bolli (1957) included a large specimen in G. kugleri, which Proto Decima and Bolli (1970) selected as the holotype of their new species G. curryi. Bolli (1972) considered G. kugleri as a subspecies of G. mexicana. According to him, G. kugleri differs from mexicana and barri in having larger, more globular chambers arranged in a loosely coiled initial spire, resulting in less compact shape. However, Bolli (1972) also included two specimens that have typical kugleri morphology (his pl. 2, figs. 15-16) in G. barri because of the presence of bullae. In disagreement with Bolli (1972), we consider these two specimens as belonging to G. kugleri. In fact, G. kugleri differs from mexicana and barri in having a much less compact test, which is subtriangular in outline, becoming subglobular only because of bullae, more depressed sutures, a much looser coiling-mode and more rapidly enlarging globular chambers in the last whorl. It differs from G. curryi by its subtriangular and more lobate outline, shorter initial spire with less numerous chambers, and smaller size which never exceeds 0.5 mm. The specimen illustrated by Bronnimann (1952) in text-figs. 3d-f as G. barri was later included in G. kugleri (Globigerapsis) by Bolli and others (1957, p. 34), an attribution followed here, even though Bolli (1972) included the same specimen in G. mexicana mexicana, as suggested by Saito (1962).
Some specimens identified by Blow (1979) as G. mexicana mexicana (pl. 198, figs. 2, 4-5) and G. mexicana howei (pl. 198, fig. 6) show a subtriangular test outline and the last two chambers are almost of the same size. Both these features are more typical of G. kugleri than of G. mexicana, whereas the specimen attributed to G. howei does not possess a bulla; consequently, they are all included under G. kugleri.
Blow (1979) considered G. subconglobata as a junior synonym of G. kugleri (p. 819), but according to our researches, these two species are discrete, separate taxa. [Premoli Silva et al. 2006]

Catalog entries: Globigerinoides korotkovi;

Type images:

Short diagnosis: Test subtriangular in outline, rather lobate, with three chambers in the outer whorl rapidly increasing in size as added, sutures depressed in the outer whorl; low arched primary and secondary sutural apertures that may be covered by slightly inflated bullae. G. kugleri differs from G. mexicana by the subtriangular outline, its distinct sutures and low arched apertures.

NB The short diagnoses are used in the tables of daughter-taxa to act as quick summaries of the differences between e.g. species of one genus. They have initially been copied from the diagnostic characters/distinguishing features sections of the Eocene and Paleocene Atlases, they will be edited as the site is developed.

Description


Diagnostic characters: Test subtriangular in outline, rather lobate, with three chambers in the outer whorl rapidly increasing in size as added, sutures depressed in the outer whorl; low arched primary and secondary sutural apertures that may be covered by slightly inflated bullae. G. kugleri differs from G. mexicana by the subtriangular outline, its distinct sutures and low arched apertures. [Premoli Silva et al. 2006]

Wall type: Spinose, cancellate, moderately incrusted with pores about 4 mm in diameter. [Premoli Silva et al. 2006]

Test morphology: Test shape sack-like consisting of 2 to 3 whorls arranged in a high trochospire; chambers subglobular with three chambers in the last whorl; sutures distinct, depressed, straight to slightly curved; peripheral outline rather compact; primary aperture a medium-sized subcircular arch at the junction of the sutures of the last three chambers with one subcircular secondary aperture almost identical to the primary one; other much smaller secondary apertures may be present on the spiral side of the previous chambers. [Premoli Silva et al. 2006]

Size: Dimensions of the holotype: diameter 0.35 mm; thickness 0.58 mm. [Premoli Silva et al. 2006]

Character matrix

test outline:Subcircularcoiling axis:Highchamber arrangement:Trochospiralumbilicus:Narrow
edge view:Equally biconvexumbilical or test sutures:Strongly depressedspiral sutures:Strongly depressedshell porosity:Macroperforate: >2.5
wall texture:Spinoseaperture:Interiomarginalaperture border:N/Aaccessory apertures:Sutural
periphery:N/Aumb chamber shape:Globularsp chbr shape:Globularperiph margin shape:Broadly rounded
umb depth:Deepdiameter mm:0.35width mm:breadth mm:0.58
final-whorl chambers:3.0-3.0

Biogeography and Palaeobiology


Geographic distribution: Tropical to temperate regions. [Premoli Silva et al. 2006]
Aze et al. 2011 summary: Low to middle latitudes; based on Premoli Silva et al. (2006)

Isotope paleobiology: Boersma and others (1987) recorded relatively negative ∂18O for this species from DSDP Sites 357 and 548, indicating a shallow planktonic habitat. This is supported by boron isotopic data (Pearson and Palmer, 1999). [Premoli Silva et al. 2006]
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): this study

Phylogenetic relations: According to Bolli (1972), G. kugleri is related to the G. mexicana group, but this relationship is not fully proved. On the other hand, Blow (1979) considered G. kugleri as the ancestral member of the lineage evolving to beckmanni via G. curryi and G. euganea in the middle Eocene, a hypothesis followed here. Blow (1979) also suggested that G. kugleri is linked through transitional forms to G. index. However, the specimens representing the so-called transitions (Blow, 1979, pl. 174, figs. 7-8) do not support Blow’s view. [Premoli Silva et al. 2006]

Biostratigraphic distribution

Geological Range:
Notes: It appears at the base of Zone E9 and extends up to the top of Zone E13. [Premoli Silva et al. 2006]
Last occurrence (top): within E15 zone (34.68-35.89Ma, top in Priabonian stage). Data source: Eocene Atlas
First occurrence (base): within E9 zone (43.23-43.85Ma, base in Lutetian stage). Data source: Eocene Atlas

Plot of occurrence data:

Primary source for this page: Premoli Silva et al. 2006 - Atlas of Eocene Planktonic Foraminifera, chapter 7, p. 186

References:

Berggren 1992 [sorry, not in our bibliography yet]

Blow, W.H. & Banner, F.T., (1962). The mid-Tertiary (Upper Eocene to Aquitanian) Globigerinaceae. In: Eames, F.E. et al. (Editors), Fundamentals of mid-Tertiary Stratigraphical Correlation. Cambridge University Press, Cambridge, pp. 61-151.

Blow, W.H., (1969). Late middle Eocene to Recent planktonic foraminiferal biostratigraphy. In: Bronnimann, P. and Renz, H.H. (Editors), Proceedings of the First International Conference on Planktonic Microfossils, Geneva, 1967, Leiden, Netherlands, pp. 380-381.

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, 1413 pp.

Bolli, H.M., (1972). The genus Globigerinatheka Bronnimann. Journal of Foraminiferal Research, 2(3): 109-136.

Collection 2831 [sorry, not in our bibliography yet]

description & Bolli 1972 Globigerinatheka [sorry, not in our bibliography yet]

Finlay 1945 [sorry, not in our bibliography yet]

Hornibrook, N.d.B., (1958). New Zealand Upper Cretaceous and Tertiary foraminiferal zones and some overseas correlations. Micropaleontology, 4: 25-38.

Keller, B.M., (1946). Foraminifera of the Late Cretaceous deposits of the Sochi region. Biulletin Moskovskogo Obshchestvo Ispytateley Prirody, otd. Geologiy, 21: 83-108.

Loeblich, A.R., Jr. & Tappan, H., (1957). Planktonic foraminifera of Paleocene and early Eocene Age from the Gulf and Atlantic coastal plains. In: Loeblich, A.R., Jr. et al. (Editors), Studies in Foraminifera, U.S. National Museum Bulletin 215. U.S. Government Printing Office, Washington, D.C., pp. 173-198.

Nocchi, M.; Amici, E. & Premoli Silva, I., (1991). Planktonic foraminiferal biostratigraphy and paleoenvironmental interpretation of Paleogene faunas from the subantarctic transect, Leg 114. In: Ciesielski, P.F., Kristoffersen, Y. and al., e. (Editors), Proceedings of the Ocean Drilling Program, Scientific Results. Ocean Drilling Program, College Station, Texas, pp. 233-273.

Premoli Silva & Spezzaferri 1990 [sorry, not in our bibliography yet]

Premoli Silva, I.; Wade, B.S. & Pearson, P.N., (2006). Taxonomy, biostratigraphy, and phylogeny of Globigerinatheka and Orbulinoides. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Allen Press, Lawrence, Kansas, pp. 169-212.

Samuel, O. & Salaj, J., (1968). Microbiostratigraphy and Foraminifera of the Slovak Carpathian Paleogene. Geologicky Ustav Dionyza Stura, Bratislava: 1-232.

Stainforth, R.M.; Lamb, J.L.; Luterbacher, H.; Beard, J.H. & Jeffords, R.M., (1975). Cenozoic planktonic foraminiferal zonation and characteristics of index forms. The University of Kansas Paleontological Contributions, 62: 1-425.

Toumarkine, M., (1975). Middle and Late Eocene planktonic foraminifera from the northwestern Pacific Ocean: Leg 32 of the Deep Sea Drilling Project. Initial Reports of the Deep Sea Drilling Project, 32: 735-751.

Toumarkine, M., (1978). Planktonic foraminiferal biostratigraphy of the Paleogene of Sites 360 to 364 and the Neogene of Sites 362A, 363 and 364 Leg 40,. Initial Reports of the Deep Sea Drilling Project, 40: 679-721.

Toumarkine, M., (1983). Les Foraminifères planctoniques de l’Eocène moyen et supérieur des régions tropicales à temperées chaudes. PhD Thesis, Université Pierre et Marie Curie, Paris 6, 83-05, 1-219 pp.


Globigerinatheka korotkovi compiled by the pforams@mikrotax project team viewed: 23-5-2017

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